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Park, Seong-Hyun, Kiyoon Yi, Peipei Liu, Gwanghwo Choi, Kyung-Young Jhang e Hoon Sohn. "In situ and layer-by-layer grain size estimation in additively manufactured metal components using femtosecond laser ultrasonics". Journal of Laser Applications 35, n.º 2 (maio de 2023): 022002. http://dx.doi.org/10.2351/7.0000938.
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Directed energy deposition (DED) is an additive manufacturing technique wherein a focused thermal energy source and a coaxial powder delivery system are combined for the fabrication of metallic parts. Although rapid progress has been made in DED, the amount of research performed for in situ quality monitoring during fabrication is limited. Grain size monitoring during DED is particularly important because the grain size is directly related to the mechanical strength and stiffness of the final products. In this study, a layer-by-layer grain size estimation technique using femtosecond laser ultrasonics is developed for in situ monitoring during DED. The proposed technique employs fully noncontact and nondestructive testing for grain size estimation and uses the relationship between the laser-induced ultrasonic waves and the grain size. In addition to the in situ operation of the technique, spatial resolution in the micrometer range was achieved. The developed technique was validated using Ti-6Al-4V specimens fabricated by DED. The results of the quantitative grain sizes measured by the developed method were consistent with those measured through independent metallography conducted after the completion of DED.
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Chen, Lequn, Xiling Yao, Youxiang Chew, Fei Weng, Seung Ki Moon e Guijun Bi. "Data-Driven Adaptive Control for Laser-Based Additive Manufacturing with Automatic Controller Tuning". Applied Sciences 10, n.º 22 (10 de novembro de 2020): 7967. http://dx.doi.org/10.3390/app10227967.
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Closed-loop control is desirable in direct energy deposition (DED) to stabilize the process and improve the fabrication quality. Most existing DED controllers require system identifications by experiments to obtain plant models or layer-dependent adaptive control rules, and such processes are cumbersome and time-consuming. This paper proposes a novel data-driven adaptive control strategy to adjust laser voltage with the melt pool size feedback. A multitasking controller architecture is developed to incorporate an autotuning unit that optimizes controller parameters based on the DED process data automatically. Experimental validations show improvements in the geometric accuracy and melt pool consistency of controlled samples. The main advantage of the proposed controller is that it can adapt to DED processes with different part shapes, materials, tool paths, and process parameters without tweaking. System identification is not required even when process conditions are changed, which reduces the controller implementation time and cost for end-users.
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Millon, Célia, Arnaud Vanhoye e Anne-Françoise Obaton. "Ultrasons laser pour la détection de défauts sur pièces de fabrication additive métallique". Photoniques, n.º 94 (novembro de 2018): 34–37. http://dx.doi.org/10.1051/photon/20189434.
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La fabrication additive (FA), notamment la FA de pièces métalliques, connait un essor dans les secteurs de pointe comme l’aéronautique ou le médical de par les possibilités accrues en termes de complexité géométrique, de fonctionnalités ou encore de personnalisation des pièces. Cependant, les poudres métalliques et la fusion laser mis en oeuvre dans certains procédés lors de la fabrication conduisent parfois à des défauts, comme par exemple des manques de fusion. Pour réduire les coûts de production engendrés par des pièces finies mais non conformes, la fabrication de ces pièces appelle à développer un contrôle en ligne. Les ultrasons laser (UL), non destructifs et sans contact, sont une piste prometteuse : ils combinent la sensibilité d’un contrôle par ultrasons avec la flexibilité d’un système optique.
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Saboori, Abdollah, Alberta Aversa, Giulio Marchese, Sara Biamino, Mariangela Lombardi e Paolo Fino. "Microstructure and Mechanical Properties of AISI 316L Produced by Directed Energy Deposition-Based Additive Manufacturing: A Review". Applied Sciences 10, n.º 9 (9 de maio de 2020): 3310. http://dx.doi.org/10.3390/app10093310.
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Directed energy deposition (DED) as a metal additive manufacturing technology can be used to produce or repair complex shape parts in a layer-wise process using powder or wire. Thanks to its advantages in the fabrication of net-shape and functionally graded components, DED could attract significant interest in the production of high-value parts for different engineering applications. Nevertheless, the industrialization of this technology remains challenging, mainly because of the lack of knowledge regarding the microstructure and mechanical characteristics of as-built parts, as well as the trustworthiness/durability of engineering parts produced by the DED process. Hence, this paper reviews the published data about the microstructure and mechanical performance of DED AISI 316L stainless steel. The data show that building conditions play key roles in the determination of the microstructure and mechanical characteristics of the final components produced via DED. Moreover, this review article sheds light on the major advancements and challenges in the production of AISI 316L parts by the DED process. In addition, it is found that in spite of different investigations carried out on the optimization of process parameters, further research efforts into the production of AISI 316L components via DED technology is required.
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Sidun, Muhammad Irfan Syahmi, e Ismayuzri Ishak. "Bead Characterization for Wire Based Laser Directed Energy Deposition Fabrication Process". Jurnal Teknologi 13, n.º 2 (30 de dezembro de 2023): 58–64. http://dx.doi.org/10.35134/jitekin.v13i2.98.
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A three-dimensional, solid object of almost any shape or design can be created using metal additive manufacturing, often known as metal 3D printing. One of the most popular materials utilized in additive manufacturing is metal. The far more complicated procedure of directed energy deposition (DED) is frequently employed to upgrade or repair existing components. DED fabrication process will be able to construct a 3D metal object with consideration of the weld bead characteristics. Without knowing the weld bead characteristics, the mechanical integrity will not hold as the bead size is not suitable for the product. In the current study, we will study the effect of variation of parameters of the DED machine to be able to print in a continuous deposition and we will also investigate the weld bead characteristics printed by the variation of parameters with the use of DED machine. The variation of parameters of the machine are the laser power with the unit of Watt and the feedrate of the machine with the unit of mm per minute. Nine preliminary samples are printed to check whether the bead can be printed in a continuous line or not. The value of variation of parameters that bring about a continuous deposition will be jotted and continued to be taken to bead characterization for study. Six samples were printed, and the bead width and height are calculated based on the variation of parameters. Based on the result, we found that laser power will increase the bead width, but the bead height needs optimal laser power which is at 473 Watt and optimal feedrate which is on 60 mm per min to reach optimal bead height which is at 2.1162 mm. The effect of the machine feedrate on the other hand is inconsistent, thus more samples need to be gathered.
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Jedlan, Štěpán, Martin Ševeček, Antonín Prantl, Josef Hodek, Pavel Podaný e Michal Brázda. "Effect of heat-treatment on material properties of L-DED printed austenistic alloy 08CH18N10T for nuclear reactor applications". Acta Polytechnica CTU Proceedings 44 (1 de dezembro de 2023): 1–4. http://dx.doi.org/10.14311/app.2023.44.0001.
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This paper deals with the evaluation of material properties of the additively manufactured austenistic alloy 08CH18N10T, which is widely used in the Czech Republic nuclear power plants Temelín and Dukovany and other VVER reactors around the world. For purposes of utilization of additive manufacturing technologies for nuclear core components fabrication, two sets of samples were prepared from horizontally and vertically L-DED printed blocks from 08CH18N10T material. Experiments such as microstructure analysis, porosity and Vickers hardness were then performed on L-DED printed and heat-treated 08CH18N10T material, and the obtained material properties were then compared with the properties of L-DED printed 08CH18N10T material without heat-treatment for examination of its effect and also with material properties of conventionally made 08CH18N10T material.
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Ostolaza, Marta, Jon Iñaki Arrizubieta, Aitzol Lamikiz, Soraya Plaza e Naiara Ortega. "Latest Developments to Manufacture Metal Matrix Composites and Functionally Graded Materials through AM: A State-of-the-Art Review". Materials 16, n.º 4 (20 de fevereiro de 2023): 1746. http://dx.doi.org/10.3390/ma16041746.
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Multi-material structure fabrication has the potential to address some critical challenges in today’s industrial paradigm. While conventional manufacturing processes cannot deliver multi-material structures in a single operation, additive manufacturing (AM) has come up as an appealing alternative. In particular, laser-directed energy deposition (L-DED) is preferred for multi-material AM. The most relevant applications envisioned for multi-material L-DED are alloy design, metal matrix composites (MMC), and functionally graded materials (FGM). Nonetheless, there are still some issues that need to be faced before multi-material L-DED is ready for industrial use. Driven by this need, in this literature review, the suitability of L-DED for multi-material component fabrication is first demonstrated. Then, the main defects associated with multi-material L-DED and current opportunities and challenges in the field are reported. In view of the industrial relevance of high-performance coatings as tools to mitigate wear, emphasis is placed on the development of MMCs and FGMs. The identified challenges include—but are not limited to—tightly controlling the composition of the multi-material powder mixture injected into the melt pool; understanding the influence of the thermal history of the process on microstructural aspects, including the interactions between constituents; and studying the in-service behaviours of MMCs and FGMs with regard to their durability and failure modes.
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Santaolaya, Javier, Jorge Sogorb, Ignacio González-Barba, Antonio Periñán e Fernando Lasagni. "Development and Optimization of Processing Parameters of 316L Stainless Steel and Inconel 718 by Wire Feed Direct Energy Deposition/Laser Beam (W-DED/LB)". Key Engineering Materials 958 (5 de outubro de 2023): 21–29. http://dx.doi.org/10.4028/p-3mi1yv.
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Within the technologies that make up Additive Manufacturing (AM), one of the ones that have taken the greatest prominence in recent times is DED (Direct Energy Deposition), particularly that of wire feedstock. The W-DED/LB technique has some benefits compared to other AM methods, such as the fabrication of relatively larger parts, repair capabilities of the damaged areas of a component, cladding of different materials on existing parts, and reduced material waste.This study describes the optimisation of processing parameters for the manufacturing stainless steel (SS316L) and Inconel 718 alloys (INC718) using W-DED/LB. This is performed by modifying processing aspects like deposition trajectories, laser power, displacement speeds of the DED head, etc, with the aim of obtaining high deposition rates and a density above 99.5%. Once the alloy systems are optimised, a characterisation campaign has been performed, which includes a series of tests as well for defectology analysis using X-ray Computed Tomography (CT). Finally, the influence of different heat treatments on the tensile behaviour is analysed.This work has developed the technology of DED assembling in a Kuka-robot, so the challenge has not only been to control the DED system, but also the communication with the robotic arm to guarantee perfect harmony between all the parts that make up the W-DED/LB system.
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Müller, M., C. C. Labisch, L. Gerdt, L. Bach, M. Riede, J. Kaspar, E. López, F. Brueckner, M. Zimmermann e C. Leyens. "Multimaterial direct energy deposition: From three-dimensionally graded components to rapid alloy development for advanced materials". Journal of Laser Applications 35, n.º 1 (fevereiro de 2023): 012006. http://dx.doi.org/10.2351/7.0000788.
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Laser-based direct energy deposition (L-DED) with blown powder enables the simultaneous or sequential processing of different powder materials within one component and, thus, offers the possibility of additive multimaterial manufacturing. Therefore, the process allows a spatially resolved material allocation and fabrication of sharp or even graded material transitions. Within this contribution, the latest results from two major research fields in multimaterial L-DED—(I) automation and (II) rapid alloy development of high entropy alloys (HEAs) by in situ synthesis—shall be presented. First, an automated multimaterial deposition process was developed, which enables the automated manufacturing of three-dimensionally graded specimens. For this, a characterization of the deposition system regarding powder feeding dynamics and resulting powder mixtures in the process zone was conducted. The obtained system characteristics were used to achieve a three-dimensional deposition of specified powder mixtures. The fabricated specimens were analyzed by energy-dispersive x-ray spectroscopy, scanning electron microscopy, and micro hardness measurement. The research demonstrates the increasing readiness of L-DED for the fabrication of multimaterial components. Second, the latest results from rapid alloy development for HEAs by DED are presented. By the simultaneous usage of up to four powder feeders, a vast range of alloy compositions within the Al–Ti–Co–Cr–Fe–Ni HEA system was investigated. For this, tailored measurement systems such as an in-house developed powder sensor were beneficially used. The study shows the influence of a variation of Al on the phase formation and resulting mechanical properties and demonstrates the potential of L-DED for reducing development times for new alloys.
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Aydogan, Beytullah, e Himanshu Sahasrabudhe. "Enabling Multi-Material Structures of Co-Based Superalloy Using Laser Directed Energy Deposition Additive Manufacturing". Metals 11, n.º 11 (27 de outubro de 2021): 1717. http://dx.doi.org/10.3390/met11111717.
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Cobalt superalloys such as Tribaloys are widely used in environments that involve high temperatures, corrosion, and wear degradation. Additive manufacturing (AM) processes have been investigated for fabricating Co-based alloys due to design flexibility and efficient materials usage. AM processes are suitable for reducing the manufacturing steps and subsequently reducing manufacturing costs by incorporating multi-materials. Laser directed energy deposition (laser DED) is a suitable AM process for fabricating Co-based alloys. T800 is one of the commercially available Tribaloys that is strengthened through Laves phases and of interest to diverse engineering fields. However, the high content of the Laves phase makes the alloy prone to brittle fracture. In this study, a Ni-20%Cr alloy was used to improve the fabricability of the T800 alloy via laser DED. Different mixture compositions (20%, 30%, 40% NiCr by weight) were investigated. The multi-material T800 + NiCr alloys were heat treated at two different temperatures. These alloy chemistries were characterized for their microstructural, phase, and mechanical properties in the as-fabricated and heat-treated conditions. SEM and XRD characterization indicated the stabilization of ductile phases and homogenization of the Laves phases after laser DED fabrication and heat treatment. In conclusion, the NiCr addition improved the fabricability and structural integrity of the T800 alloy.
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Booysen, Theo-Neal, Tamba Jamiru, Taoreed Adegbola e Nana Arthur. "Microstructural effects on properties of as-fabricated Inconel 625 with direct energy deposition process". MATEC Web of Conferences 388 (2023): 08001. http://dx.doi.org/10.1051/matecconf/202338808001.
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Three-dimensional printing (3D), also known as metal additive manufacturing (MAM), fabricates parts or components from different feedstocks: wires, powders or sheets. This process differs from traditional manufacturing techniques such as casting, moulding, or subtracting existing materials. In the development and improvement or fabrication of new materials for higher strength and various applications, the type or character of a material is very important as this will ascertain the strength of the finished product. Direct energy technology can be used to fabricate and repair parts or components with the following two fabrication methods: laser wire-directed energy deposition (LW-DED) or laser powder-directed energy deposition (LP-DED). In this research, laser powder-directed energy deposition (LP-DED), a MAM process method, was employed to fabricate Inconel 625. The LP-DED process uses a laser as a heat source and rapidly melts metallic powders of different chemical compositions to fabricate complex structures, which is an innovative three-dimensional material processing technology. The as-fabricated (AF) sample specimens were investigated to determine the microstructural development, microhardness and sample defects. The microstructural features were analysed using two experimental surface microscopy methods: light optical microscopy (LOM) and scanning electron microscopy (SEM). The morphological grain structure within the samples was predominantly cellular, columnar and columnar-dendritic. Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis were performed to determine the chemical composition and crystallographic structures of virgin gas atomisation (GA) powder and as-fabricated sample. The XRD peaks in samples composed of face-centred-cubic (FCC) γ-nickel phase. The material microhardness was studied by performing Rockwell hardness test (HRB) with a fluctuated trend averaging 98.9 – 101.6 HRB. The relationship between processing, microstructure, grain structure and material hardness was systematically summarised and established. The study concluded with research suggestions on LP-DED of Inconel 625.
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Morales, Cindy, Annalisa Fortini, Chiara Soffritti e Mattia Merlin. "Effect of Post-Fabrication Heat Treatments on the Microstructure of WC-12Co Direct Energy Depositions". Coatings 13, n.º 8 (19 de agosto de 2023): 1459. http://dx.doi.org/10.3390/coatings13081459.
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Laser-Directed Energy Deposition (L-DED) is an additive manufacturing technique that has lately been employed to deposit coatings of cemented carbides, such as WC-Co. During deposition, complex microstructural phenomena usually occur, strongly affecting the microstructural and mechanical behavior of the coatings. Post-fabrication heat treatments (PFHTs) may be applied to homogenize and strengthen the microstructure; nevertheless, to the best of the authors’ knowledge, just a few papers deepened the effect of these treatments on cemented carbides fabricated by additive manufacturing. This work evaluates the influence of four PFHTs on the microstructural evolution and hardness of L-DED WC-12Co. For each treatment, different combinations of solubilization time and temperature (between 30 and 180 min and from 400 °C to 700 °C, respectively) were adopted. The microstructure was investigated by optical and scanning electron microscopy equipped with energy-dispersive spectroscopy, whereas the mechanical properties were determined by Vickers hardness measurements. Based on the results, high microstructural heterogeneity in terms of WC particles, η-phase structures, and Co distribution was observed in the sample in the as-built condition. Some cracking defects were also observed in the samples, irrespective of the heat treatment conditions. Finally, a finer microstructure and a lower amount of brittle ternary η-phase, together with an increase in hardness (1030 ± 95 HV10), were found for the highest dwelling times (180 min) and for solubilization temperatures in the range of 500–600 °C.
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Dussa, Saikumar, Sameehan S. Joshi, Shashank Sharma, Karri Venkata Mani Krishna, Madhavan Radhakrishnan e Narendra B. Dahotre. "Additively Manufactured Alnico Permanent Magnet Materials—A Review". Magnetism 4, n.º 2 (30 de maio de 2024): 125–56. http://dx.doi.org/10.3390/magnetism4020010.
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Additive manufacturing offers manufacturing flexibility for intricate components and also allows for precise control over the microstructure. This review paper explores the current state of the art in additive manufacturing techniques for Alnico permanent magnets, emphasizing the notable advantages and challenges associated with this innovative approach. Both the LPBF and L-DED processes have demonstrated promising results in fabricating Alnico with magnetic properties comparable with conventionally processed samples. The optimization of process parameters successfully reduced porosity and cracking in the LPBF processing of Alnico. The review further explored the significance of additive manufacturing process parameter optimization in managing the temperature gradient and solidification rate for a desired microstructure and enhanced magnetic properties. Other potential additive manufacturing methods suitable for the fabrication of Alnico were discussed, along with the challenges associated with the process. The insights provided also highlight how additive manufacturing holds the potential to replace post-processing techniques like solutionization, magnetic annealing, and tempering often necessary in Alnico production.
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Froes, F. H., e B. Dutta. "The Additive Manufacturing (AM) of Titanium Alloys". Advanced Materials Research 1019 (outubro de 2014): 19–25. http://dx.doi.org/10.4028/www.scientific.net/amr.1019.19.
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High cost is the major reason that there is not more wide-spread use of titanium alloys. Powder Metallurgy (P/M) represents one cost effective approach to fabrication of titanium components and Additive Manufacturing (AM) is an emerging attractive PM Technique . In this paper AM is discussed with the emphasis on the “work horse” titanium alloy Ti-6Al-4V. The various approaches to AM are presented and discussed, followed by some examples of components produced by AM. The microstructures and mechanical properties of Ti-6Al-4V produced by AM are listed and shown to compare very well with cast and wrought product. Finally, the economic advantages to be gained using the AM technique compared to conventionally processed material are presented. Key words: Additive Manufacturing (AM), 3D Printing, CAD, CAM, Laser, Electron beam, near net shape, remanufacturing, Powder Bed Fusion (PBF), Direct Energy Deposition (DED)
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Çallı, Metin, Emre İsa Albak e Ferruh Öztürk. "Prediction and Optimization of the Design and Process Parameters of a Hybrid DED Product Using Artificial Intelligence". Applied Sciences 12, n.º 10 (16 de maio de 2022): 5027. http://dx.doi.org/10.3390/app12105027.
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Directed energy deposition (DED) is an additive manufacturing process used in manufacturing free form geometries, repair applications, coating and surface modification, and fabrication of functionally graded materials. It is a process in which focused thermal energy is used to fuse materials by melting. Thermal effects can cause distortions and defects on the parts during the DED process, therefore they should be evaluated and taken into account during the manufacturing of products. Melting pool control and DED bead geometries should be defined properly as well. In this work, an Artificial Neural Network model has been applied considering the DED process parameters in order to predict the geometrical patterns and create a local reinforced product as a hybrid manufacturing technology. Although lots of studies are available on topology optimization for manufacturing methods such as casting, extrusion, and powder bed fusion, topology optimization for the DED process is not widely taken into consideration to predict the design geometrical patterns. DOE RSM and ANN approaches were applied in this study to predict convenient dimensions, topology based geometrical patterns of local stiffeners and heat source power optimizing the energy, total mass, and peak force results of the hybrid part. A single bead track deposition is simulated in terms of validation of the numerical heat source model, and cross-sections of the beads are analysed. A cross-member structure is manufactured using the DED device and the structure is correlated under the three point bending physical conditions on test bench. It has been investigated that locally reinforced cross beam has much more energy absorption and peak force values than plain model. The results showed that the proposed NN-GA is a promising approach to generate the topology based geometrical patterns and process parameters which can be used to create a local reinforced product as hybrid manufacturing technologies.
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Aldalur, Eider, Fernando Veiga, Alfredo Suárez, Jon Bilbao e Aitzol Lamikiz. "Analysis of the Wall Geometry with Different Strategies for High Deposition Wire Arc Additive Manufacturing of Mild Steel". Metals 10, n.º 7 (4 de julho de 2020): 892. http://dx.doi.org/10.3390/met10070892.
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Additive manufacturing has gained relevance in recent decades as an alternative to the manufacture of metal parts. Among the additive technologies, those that are classified as Directed Energy Deposition (DED) are characterized by their high deposition rate, noticeably, Wire Arc Additive Manufacturing (WAAM). However, having the inability to produce parts with acceptable final surface quality and high geometric precision is to be considered an important disadvantage in this process. In this paper, different torch trajectory strategies (oscillatory motion and overlap) in the fabrication of low carbon steel walls will be compared using Gas Metal Arc Welding (GMAW)-based WAAM technology. The comparison is done with a study of the mechanical and microstructural characteristics of the produced walls and finally, addressing the productivity obtained utilizing each strategy. The oscillation strategy shows better results, regarding the utilization rate of deposited material and the flatness of the upper surface, this being advantageous for subsequent machining steps.
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Ali, Nashit, Luca Tomesani, Alessandro Ascari e Alessandro Fortunato. "Fabrication of Thin Walls with and without Close Loop Control as a Function of Scan Strategy Via Direct Energy Deposition". Lasers in Manufacturing and Materials Processing 9, n.º 1 (1 de fevereiro de 2022): 81–101. http://dx.doi.org/10.1007/s40516-022-00164-8.
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AbstractDirect Energy Deposition (DED) is a technique used to fabricate metallic parts and is a subcategory of metal additive manufacturing. Despite of its vast advantages over traditional manufacturing the deployment at industrial level is still limited due to underlaying concerns of process stability and repeatability. In-situ monitoring, therefore, is indispensable while depositing via DED. The present experiment is a step towards enhancing our current understanding of the DED when coupled with a closed loop control system to control melt pool width for deposition of thin-walled structures, and as a function of scan strategy. 316L stainless steel powder was deposited on S235JR substrate. A total of 6 iterations are reported, out of many performed, of which 3 were without the closed loop control. Also, to understand the effect of scan strategy as a function of laser power. Two different scan strategies were employed for understanding of the issue i.e., unidirectional, and bidirectional. Apart from the geometrical consistency of the wall, microhardness, density calculations and microstructure were investigated. The geometric consistency was found to be almost perfect with the bidirectional scan strategy. In case of unidirectional scan strategy, the wall shows a negative slope along the other extreme regardless of the closed loop control system. Dilution zone shows the hardness greater than both the substrate and the wall. The specimens fabricated without the use of closed loop control were found to be denser than their counterparts. This was found to be true also in case of manual reduction of power during each layer.
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Gudur, Srinath, Suryakumar Simhambhatla e N. Venkata Reddy. "Enhancing the Shape Complexity in Direct Energy Deposition with Phased Deformation". International Journal of Automation Technology 16, n.º 5 (5 de setembro de 2022): 642–53. http://dx.doi.org/10.20965/ijat.2022.p0642.
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Wire-based direct energy deposition (W-DED) techniques in metal additive manufacturing allow part-fabrication at higher deposition rates and lower costs. Given the lack of any support mechanism, these processes face challenges in fabricating overhanging features. The inherent overhang capability of weld-beads and higher-order kinematics can help realize certain complex geometries. However, significant challenges like non-uniform slicing, constrained deposition-torch accessibility, etc., limit the efficacy of these approaches. The present work describes a deformation-aided deposition process designed to overcome some of these limitations and to manufacture complex metallic components. It is based on a sequential combination of deposition and bending processes: a shape fabricated through W-DED deposition is bent to form the required shape. The cycle of deposition and bending is repeated until the final desired geometry is realized. The anisotropic and deterministic behaviors of the deposited components are analyzed in terms of springback and the punch force. Finally, the benefit of current hybrid process is demonstrated through a few illustrative geometries.
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Ratnala, Dilipkumar Choudary, Joel Andersson e Shrikant Joshi. "Development of Functionally Graded Metal-Ceramic Systems by Directed Energy Deposition: A Review". Materials Science Forum 1107 (6 de dezembro de 2023): 105–10. http://dx.doi.org/10.4028/p-4ekatd.
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Ceramics and metals are the two vastly explored classes of materials whose individual characteristics and targeted applications differ significantly. Continuous thrust for space exploration and energy generation demands materials with a wide range of properties. To tackle this demand, ceramic-metal combined structures that club heat, wear, and corrosion resistance of ceramics to the high toughness, good strength, and better machinability of metals are desirable. While various processing routes to combine ceramics and metals have been developed through the years, solutions to address problems associated with the interface, thermal property mismatch, and poor adhesion need to be explored. In this context, Functional Graded Materials (FGMs) have attracted particular attention by virtue of their ability to avoid sharp interfaces and local stress concentrations. Out of all, Additive Manufacturing (AM) routes, particularly the Directed Energy Deposition (DED) technique, is emerging as a productive technique capable of fabricating a wide range of metal-ceramic graded structures. This paper specifically discusses metal-ceramic FGMs ́ capability as a potential high-temperature material with customized multifunctional material properties. It further outlines the primary concerns with the realization of metal-ceramic graded structures and major techniques developed to mitigate problems encountered in processing them. Specific emphasis is laid on the powder-based Laser DED (L-DED) technique of FGM fabrication owing to its control over complex geometries and microstructural engineering.
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Pathak, Puskar, Goran Majkic e Venkat Selvamanickam. "Role of customized scan strategies and dwell time on microstructure and properties of additively manufactured 316L stainless steel". Materials Science in Additive Manufacturing 3, n.º 1 (8 de março de 2024): 2676. http://dx.doi.org/10.36922/msam.2676.
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Direct energy deposition (DED)-based additive manufacturing facilitates fabrication of medium-to-large functional parts. This study assesses the role of varying scan strategies and dwell time between each layer to control the cooling rate of 316L stainless steel produced by the laser-engineered net shaping-DED method. Customized print patterns were designed, keeping other optimized print parameters constant to obtain printed parts with better dimensional tolerance. The parts, which were >99% dense, were fabricated in a controlled argon environment. A heterogeneous microstructure consisting of a cellular columnar and equiaxed substructure was obtained. Two-dimensional X-ray diffraction revealed the presence of a single-phase γ-austenitic FCC phase. A refined microstructure with less elemental segregation was noticed with an increase in dwell time between the print layers. Internal defect analysis using X-ray micro-computed tomography revealed low lack-of-fusion voids along the build direction without any micro-cracks, which is attributed to higher cooling rates between subsequent print layers. As demonstrated in a mechanical performance evaluation of tensile and micro-hardness properties, better performance can be achieved by controlling the cooling rate and customizing deposition patterns.
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Ning, Jinsheng, Lida Zhu, Shuhao Wang, Zhichao Yang, Peihua Xu, Pengsheng Xue, Hao Lu et al. "Printability disparities in heterogeneous material combinations via laser directed energy deposition: a comparative study". International Journal of Extreme Manufacturing 6, n.º 2 (4 de janeiro de 2024): 025001. http://dx.doi.org/10.1088/2631-7990/ad172f.
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Abstract Additive manufacturing provides achievability for the fabrication of bimetallic and multi-material structures; however, the material compatibility and bondability directly affect the parts’ formability and final quality. It is essential to understand the underlying printability of different material combinations based on an adapted process. Here, the printability disparities of two common and attractive material combinations (nickel- and iron-based alloys) are evaluated at the macro and micro levels via laser directed energy deposition (DED). The deposition processes were captured using in situ high-speed imaging, and the dissimilarities in melt pool features and track morphology were quantitatively investigated within specific process windows. Moreover, the microstructure diversity of the tracks and blocks processed with varied material pairs was comparatively elaborated and, complemented with the informative multi-physics modeling, the presented non-uniformity in mechanical properties (microhardness) among the heterogeneous material pairs was rationalized. The differences in melt flow induced by the unlike thermophysical properties of the material pairs and the resulting element intermixing and localized re-alloying during solidification dominate the presented dissimilarity in printability among the material combinations. This work provides an in-depth understanding of the phenomenological differences in the deposition of dissimilar materials and aims to guide more reliable DED forming of bimetallic parts.
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Liu, Chen, Yu Zhan, Hongjian Zhao, Shuo Shang e Changsheng Liu. "The Effect of Process Parameters on the Temperature and Stress Fields in Directed Energy Deposition Inconel 690 Alloy". Materials 17, n.º 6 (14 de março de 2024): 1338. http://dx.doi.org/10.3390/ma17061338.
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Additive manufacturing (AM) technology has the advantages of designability, short process times, high flexibility, etc., making it especially suitable for manufacturing complex high-performance components for high-end industrial systems. However, the intensive temperature gradients caused by the rapid heating and cooling processes of AM can generate high levels of residual stresses, which directly affect the precision and serviceability of the components. Taking Inconel 690 alloy, which is widely used in nuclear power plants, as the research object, a thermo-coupled mechanical model of temperature field and residual stress field of directed energy deposition (DED) of Inconel 690 was established based on ABAQUS 2019 finite element software to study the influence of process parameters on the temperature history and the distribution of residual stresses in the DED process. The experimental results show that the peak temperature of each layer in the fabrication process increases with the increase in laser power and preheating temperature, and decreases with the increase in scanning speed and interlayer dwell time. Substrate preheating only has a large effect on the peak temperature of the first four layers. Residual stresses are mainly concentrated in the upper and middle parts, the bottom of the substrate, and the sides combined with the substrate, and the residual stresses increase with the increasing laser power and decrease with the increasing interlayer dwell time. Decreasing laser power, longer dwell time, higher preheating temperature, and appropriate scanning speed are beneficial for the reduction in residual stresses in Inconel 690 components. This research has important significance for the process design and residual stress modulation in the additive manufacturing of Inconel 690 alloy.
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White, Emma, Emily Rinko, Timothy Prost, Timothy Horn, Christopher Ledford, Christopher Rock e Iver Anderson. "Processing of Alnico Magnets by Additive Manufacturing". Applied Sciences 9, n.º 22 (12 de novembro de 2019): 4843. http://dx.doi.org/10.3390/app9224843.
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Permanent magnets without rare earth (RE) elements, such as alnico, will improve supply stability and potentially decrease permanent magnet cost, especially for traction drive motors and other increased temperature applications. Commercial alnico magnets with the highest energy product are produced by directional solidification (DS) to achieve a <001> columnar grain orientation followed by significant final machining, adding to the high cost. Additive manufacturing (AM) is an effective method to process near net-shape parts with minimal final machining of complex geometries. AM also, has potential for texture/grain orientation control and compositionally graded structures. This report describes fabrication of alnico magnets by AM using both laser engineered net shaping (LENS)/directed energy deposition (DED) and electron beam melting powder bed fusion (EBM/PBF). High pressure gas atomized (HPGA) pre-alloyed alnico powders, with high purity and sphericity, were built into cylindrical and rectangular samples, followed by magnetic annealing (MA) and a full heat treatment (FHT). The magnetic properties of these AM processed specimens were different from their cast and sintered counterparts of the same composition and show a great sensitivity to heat treatment. The AM process parameters used in this developmental study did not yet result in any preferred texture within the alnico AM builds. These findings demonstrate feasibility for near net-shape processing of alnico permanent magnets for use in next generation traction drive motors and other applications requiring increased operating temperatures and/or complex engineered part geometries, especially with further AM process development for texture control.
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Uralde, Virginia, Alfredo Suarez, Eider Aldalur, Fernando Veiga e Tomas Ballesteros. "Wall Fabrication by Direct Energy Deposition (DED) Combining Mild Steel (ER70) and Stainless Steel (SS 316L): Microstructure and Mechanical Properties". Materials 15, n.º 17 (24 de agosto de 2022): 5828. http://dx.doi.org/10.3390/ma15175828.
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Direct energy deposition is gaining much visibility in research as one of the most adaptable additive manufacturing technologies for industry due to its ease of application and high deposition rates. The possibility of combining these materials to obtain parts with variable mechanical properties is an important task to be studied. The combination of two types of steel, mild steel ER70-6 and stainless steel SS 316L, for the fabrication of a wall by direct energy deposition was studied for this paper. The separate fabrication of these two materials was studied for the microstructurally flawless fabrication of bimetallic walls. As a result of the application of superimposed and overlapped strategies, two walls were fabricated and the microstructure, mechanical properties and hardness of the resulting walls are analyzed. The walls obtained with both strategies present dissimilar regions; the hardness where the most present material is ER70-6 is around 380 HV, and for SS 316L, it is around 180 HV. The average values of ultimate tensile strength (UTS) are 869 and 628 MPa, yield strength (YS) are 584 and 389 MPa and elongation at break are 20% and 36%, respectively, in the cases where we have more ER70-6 in the sample than SS 316L. This indicates an important relationship between the distribution of the materials and their mechanical behavior.
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Andrade, David G., Carlos Zhu, Hélio C. Miranda e Dulce M. Rodrigues. "Thermal, Microstructural, and Mechanical Analysis of Complex Lattice Structures Produced by Direct Energy Deposition". Materials 17, n.º 12 (9 de junho de 2024): 2813. http://dx.doi.org/10.3390/ma17122813.
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Lattice structures have gained attention in engineering due to their lightweight properties. However, the complex geometry of lattice structures and the high melting temperature of metals present significant manufacturing challenges for the large-scale fabrication of these structures. Direct Energy Deposition (DED) methods, such as the Wire Arc Additive Manufacturing (WAAM) technique, appear to be an interesting solution for overcoming these limitations. This study provides a detailed analysis of the manufacturing process of carbon steel lattice structures with auxetic geometry. The study includes thermal analysis using infrared thermography, microstructural characterization through metallography, and mechanical evaluation via hardness and mechanical testing. The findings reveal the significant impact of heat input, thermal cycles, and deposition sequence on the morphology and mechanical properties of the lattice structures. Fast thermal cycles are related to areas with higher hardness values, smaller strut diameters, and porous formations, which shows that controlling heat input and heat dissipation is crucial for optimizing the properties of lattice structures produced using WAAM.
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Halder, Rajib, Petrus C. Pistorius, Scott Blazanin, Rigved P. Sardey, Maria J. Quintana, Edward A. Pierson, Amit K. Verma, Peter C. Collins e Anthony D. Rollett. "The Effect of Interlayer Delay on the Heat Accumulation, Microstructures, and Properties in Laser Hot Wire Directed Energy Deposition of Ti-6Al-4V Single-Wall". Materials 17, n.º 13 (4 de julho de 2024): 3307. http://dx.doi.org/10.3390/ma17133307.
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Laser hot wire directed energy deposition (LHW-DED) is a layer-by-layer additive manufacturing technique that permits the fabrication of large-scale Ti-6Al-4V (Ti64) components with a high deposition rate and has gained traction in the aerospace sector in recent years. However, one of the major challenges in LHW-DED Ti64 is heat accumulation, which affects the part quality, microstructure, and properties of as-built specimens. These issues require a comprehensive understanding of the layerwise heat-accumulation-driven process–structure–property relationship in as-deposited samples. In this study, a systematic investigation was performed by fabricating three Ti-6Al-4V single-wall specimens with distinct interlayer delays, i.e., 0, 120, and 300 s. The real-time acquisition of high-fidelity thermal data and high-resolution melt pool images were utilized to demonstrate a direct correlation between layerwise heat accumulation and melt pool dimensions. The results revealed that the maximum heat buildup temperature of the topmost layer decreased from 660 °C to 263 °C with an increase to a 300 s interlayer delay, allowing for better control of the melt pool dimensions, which then resulted in improved part accuracy. Furthermore, the investigation of the location-specific composition, microstructure, and mechanical properties demonstrated that heat buildup resulted in the coarsening of microstructures and, consequently, the reduction of micro-hardness with increasing height. Extending the delay by 120 s resulted in a 5% improvement in the mechanical properties, including an increase in the yield strength from 817 MPa to 859 MPa and the ultimate tensile strength from 914 MPa to 959 MPa. Cooling rates estimated at 900 °C using a one-dimensional thermal model based on a numerical method allowed us to establish the process–structure–property relationship for the wall specimens. The study provides deeper insight into the effect of heat buildup in LHW-DED and serves as a guide for tailoring the properties of as-deposited specimens by regulating interlayer delay.
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Müller, Christoph, Johanna Müller, Harald Kloft e Jonas Hensel. "Design of Structural Steel Components According to Manufacturing Possibilities of the Robot-Guided DED-Arc Process". Buildings 12, n.º 12 (7 de dezembro de 2022): 2154. http://dx.doi.org/10.3390/buildings12122154.
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Additive manufacturing with the DED-arc process offers limited freedom in terms of the geometric shape of work pieces. The process and fabrication systems restrict the part geometry producible, which must be taken into account during design already. For this reason, a design process was investigated in which geometry generation is based on a self-organizing system. The aim of using a self-organizing system is the possibility to directly control the geometry-defining points. Next to load cases, the design method considers geometric boundary conditions from the production process when generating the geometry. In order to identify these geometrical constraints from production experimentally, a concept of Case Study Demonstrators was applied. This was used to investigate how path planning and production can be carried out for specific geometrical features and to identify restraints of the process and the manufacturing system, e.g., smallest producible wall thickness and overhangs. Subsequently, the obtained restraints were considered as boundary conditions for the design process and were included in the modification of an example geometry. By applying the presented design method, it was possible to maintain a minimum wall thickness throughout the structure while generating a topologically optimized geometry. In contrast to compliance with the minimum wall thickness, no satisfactory behavioral rule could be found for limiting the overhang.
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Sato, Naoko, Mitsutaka Matsumoto, Hisato Ogiso e Harumichi Sato. "Challenges of Remanufacturing Using Powder Bed Fusion Based Additive Manufacturing". International Journal of Automation Technology 16, n.º 6 (5 de novembro de 2022): 773–82. http://dx.doi.org/10.20965/ijat.2022.p0773.
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Remanufacturing is an industrial process of turning used products into products with the same quality as new ones. Of the processes comprising remanufacturing, the repair process poses the greatest challenge. Additive manufacturing (AM) is expected to bring innovation to the repair process of remanufacturing. Although, so far, the directed energy deposition (DED) type AM has been most frequently applied to remanufacturing and only a few studies applied powder bed fusion (PBF) type AM to remanufacturing, PBF demonstrates great potential for application in remanufacturing. This study aims to assess the feasibility of the application of PBF to remanufacturing. We conducted an experimental PBF-based repair and attempted to identify its challenges. In the experiment, 1) we used AlSi10Mg powder, 2) we first fabricated a 5 mm square cube sample by using PBF, 3) we next removed 0.4 mm of thickness from the sample with milling, 4) then we restored 0.44 mm of thickness using PBF, and 5) we observed the restored sample. The observation showed that: 1) misalignment in the restoration occurred, 2) keyhole defects and gas pores were found more in the boundary area between the original and restored parts, and 3) the microstructures showed polycrystals in the restored part. These factors impaired the quality and reliability of PBF-based repair and present challenges of enhancing the feasibility of applying PBF-based repair to remanufacturing. This study also examined the whole process of PBF-based remanufacturing, which includes not only the repair process but also the processes of component inspection, process design, pre-repair process, and post-repair process, and discussed the challenges in these processes. The challenges include the development of repair process design methods, supportless fabrication processes, and non-destructive test (NDT) techniques.
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Noh, Inwoong, Jaehun Jeon e Sang Won Lee. "A Study on Metallographic and Machining Characteristics of Functionally Graded Material Produced by Directed Energy Deposition". Crystals 13, n.º 10 (13 de outubro de 2023): 1491. http://dx.doi.org/10.3390/cryst13101491.
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Directed energy deposition (DED) stands as a key process in metal additive manufacturing (AM) and offers the unique capability of creating functionally graded materials (FGMs). FGMs have garnered significant interest in high-value industries by advantages such as performance optimization, reducing material defects, and resolving joining issues. However, post-processing remains a crucial step, indicating a need for further research to understand the machinability of FGMs. This paper focuses on the characteristics analysis of fabricating and machining an FGM based on stainless steel 316L (SAE 316L) and Inconel 718. The FGM was fabricated by starting with SAE 316L at 100 wt.% and adjusting the composition ratio by incrementally increasing Inconel 718 by 20 wt.% while simultaneously decreasing SAE 316L. Following the FGM fabrication, microstructure and mechanical properties were comprehensively analyzed by hardness testing, optical microstructure measurements, energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). To investigate the post-processing aspects, end-milling experiments were conducted using two distinct milling methods (upward and downward milling) and machining paths (from SAE 316L towards Inconel 718, and vice versa). The mean cutting force peaked at 148.4 N in upward milling and dipped to 70.5 N in downward milling, and tool wear measurements further provided insights into the optimal milling direction when working with an FGM of SAE 316L and Inconel 718.
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Buj-Corral, Irene, Aitor Tejo-Otero e Felip Fenollosa-Artés. "Development of AM Technologies for Metals in the Sector of Medical Implants". Metals 10, n.º 5 (23 de maio de 2020): 686. http://dx.doi.org/10.3390/met10050686.
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Additive manufacturing (AM) processes have undergone significant progress in recent years, having been implemented in sectors as diverse as automotive, aerospace, electrical component manufacturing, etc. In the medical sector, different devices are printed, such as implants, surgical guides, scaffolds, tissue engineering, etc. Although nowadays some implants are made of plastics or ceramics, metals have been traditionally employed in their manufacture. However, metallic implants obtained by traditional methods such as machining have the drawbacks that they are manufactured in standard sizes, and that it is difficult to obtain porous structures that favor fixation of the prostheses by means of osseointegration. The present paper presents an overview of the use of AM technologies to manufacture metallic implants. First, the different technologies used for metals are presented, focusing on the main advantages and drawbacks of each one of them. Considered technologies are binder jetting (BJ), selective laser melting (SLM), electron beam melting (EBM), direct energy deposition (DED), and material extrusion by fused filament fabrication (FFF) with metal filled polymers. Then, different metals used in the medical sector are listed, and their properties are summarized, with the focus on Ti and CoCr alloys. They are divided into two groups, namely ferrous and non-ferrous alloys. Finally, the state-of-art about the manufacture of metallic implants with AM technologies is summarized. The present paper will help to explain the latest progress in the application of AM processes to the manufacture of implants.
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Stolidi, Adrien, Anthony Touron, Loïc Toulemonde, Audrey Gardahaut e Jean-Paul Garandet. "Monitoring en ligne par fluorescence X des procédés de fabrication additive métallique". e-journal of nondestructive testing 28, n.º 9 (setembro de 2023). http://dx.doi.org/10.58286/28476.
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Cette communication présente des résultats de spectrométrie par fluorescence X à dispersion d’énergie (ED-XRF) acquis durant des procédés de fabrication additive métallique. Cette technique de caractérisation sans contact et non-destructive est appliquée à deux techniques de fabrication additive métallique. Le but est de renforcer la maitrise de ces procédés et de répondre à des exigences de contrôle qualité. Deux cas d’études sont abordés, l’un concernant des mesures effectuées sur des échantillons possédant une gradation de la composition chimique de l’alliage, l’autre présentant le monitoring des fumées induites durant un procédé de fabrication additive.
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Lee, Jin-Woo, Soo-Jeong Park e Yun-Hae Kim. "Numerical prediction of thermal stress–strain behavior on the wire-directed energy deposition additive manufacturing for automotive component". Modern Physics Letters B, 9 de abril de 2022. http://dx.doi.org/10.1142/s0217984922420040.
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Wire-directed energy deposition (wire-DED) is used to create a shape in a layer-by-layer manner by depositing a consumable welding wire, where a welding arc is the source of heat. This technology can be used to fabricate large components with higher deposition rates compared to other 3D metal printing methods. Despite these benefits, the components of wire-DED are affected by heat distortion and residual stress. Therefore, the prediction of deformation before fabrication using wire-DED is essential for determining the range of machining for the final products. In this study, the deformation and time required were evaluated using various simulation models of wire-DED.
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Schneider, J. A., G. Puerto, E. Walker, B. T. Montgomery, P. R. Gradl, B. Walker, M. Santangelo e S. Thompson. "Wire Based Directed Energy Deposition of JBK-75". Metallurgical and Materials Transactions A, 22 de fevereiro de 2024. http://dx.doi.org/10.1007/s11661-024-07306-x.
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AbstractApplications and adoption of metal additive manufacturing (AM) are increasing for fabrication of low volume, complex components with novel materials, as well as replacement parts. While the use of powder bed fusion-based processes have been widely used to build complex components with fine feature resolution, there is a volume limitation. Expanding the application of metal AM will rely on other processes that remove this build size constraint. These processes are referred to as Directed Energy Deposition (DED) and can use either powder or wire feedstock. Wire based DED provides the highest deposition rates which shortens the fabrication time making it attractive for fabrication of large parts replacing traditional wrought billets or castings. In this study, an iron-based austenitic superalloy (JBK-75) was deposited using an arc-based, wire-fed (AW)-DED process. The material was metallographically characterized and quasi-static mechanical properties were obtained. The resulting microstructure and mechanical properties are compared with conventional wrought and cast forms of JBK-75 subjected to the same heat treatments. As compared to wrought material, the AW-DED grain size was larger after the heat treatment, although the strengths were similar. Improved homogenization was observed after heat treatment in the AW-DED specimens as compared to the cast specimens.
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Sreeramagiri, Praveen, e Ganesh Balasubramanian. "Directed Energy Deposition of Multi-Principal Element Alloys". Frontiers in Materials 9 (11 de abril de 2022). http://dx.doi.org/10.3389/fmats.2022.825276.
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As efforts associated with the exploration of multi-principal element alloys (MPEAs) using computational and data-intensive methods continue to rise, experimental realization and validation of the predicted material properties require high-throughput and combinatorial synthesis of these alloys. While additive manufacturing (AM) has emerged as the leading pathway to address these challenges and for rapid prototyping through part fabrication, extensive research on developing and understanding the process-structure-property correlations is imminent. In particular, directed energy deposition (DED) based AM of MPEAs holds great promise because of the boundless compositional variations possible for functionally graded component manufacturing as well as surface cladding. We analyze the recent efforts in DED of MPEAs, the microstructural evolution during the laser metal deposition of various transition and refractory elements, and assess the effects of various processing parameters on the material phase and properties. Our efforts suggest that the development of robust predictive approaches for process parameter selection and modifying the synthesis mechanisms are essential to enable DED platforms to repeatedly produce defect free, stable and designer MPEAs.
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Kindermann, Philipp, Maximilian Strasser, Martin Wunderer, Ismail Uensal, Max Horn e Christian Seidel. "Cold spray forming: a novel approach in cold spray additive manufacturing of complex parts using 3D-printed polymer molds". Progress in Additive Manufacturing, 13 de outubro de 2023. http://dx.doi.org/10.1007/s40964-023-00521-9.
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AbstractThe solid-state additive manufacturing (AM) process cold spraying (CS) offers advantageous properties such as melt-free near-net-shape part fabrication and high deposition rates. Compared to other metal-based AM processes such as the powder bed fusion of metals (PBF-LB/M) or directed energy deposition (DED) processes such as laser metal deposition (DED-LB), CS features lower part resolution. One solution to increase the achievable level of detail is spraying onto removable molds. No study exists that investigates the general feasibility and manufacturing boundaries, from which design guidelines could be derived. In this paper, the applicability of material extruded and thermally bonded polymer (MEX-TRB/P) shapes, which is especially suitable for flexible low-cost production of small batches, as molds for cold spray additive manufacturing (CSAM) is investigated. For this purpose, material extruded thermoplastics are examined regarding their suitability for the CS process. Furthermore, geometrical and thus constructive restrictions of this new approach “Cold Spray Forming” (CSF) are analyzed using an industry-relevant use case. It was shown that the feasibility of this approach could be determined by the material value hardness of the sprayed polymer substrates.
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Liu, Hanru, Junlin Yuan, Shitong Peng, Fengtao Wang e Weiwei Liu. "In-suit monitoring melt pool states in direct energy deposition using ResNet". Measurement Science and Technology, 5 de setembro de 2022. http://dx.doi.org/10.1088/1361-6501/ac8f62.
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Abstract One critical challenge of directed energy deposition (DED) in additive manufacturing (AM) is the lack of comprehension of the relationship between the part parameters and the formation quality. Components fabricated by the inappropriate manufacturing parameters will be too unreliable to satisfy the strict requirements of industrial applications. To address these issues, the present study established an experiment with a coaxial high-speed CCD camera to monitor the 316L deposition process and developed a data-driven model with ResNet101 to identify different melt pool states. We adopted the t-distributed Stochastic Neighbor Embedding (t-SNE) clustering algorithm, accuracy rate, and normalized confusion matrix (NCM) to evaluate the performance of ResNet101. Furthermore, the visualization technique class activation mapping (CAM) was used to analyze the morphological characteristics of the melt pool formed under different experimental parameters, explained the classification behavior of the ResNet101 model. The result indicated that RseNet101 gains better feature extraction and higher capability to classify different melt pool states with an average accuracy of 99.07%, compared with other CNNs (LeNet, GoogLeNet, AlexNet, ResNet34, and ResNet50) model. This demonstrated the effectiveness of ResNet101 in monitoring the DED process and the potential to reduce fabrication costs in DED.
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Zhou, Yue, e Fuda Ning. "Directed Energy Deposition with Coaxial Wire-Powder Feeding: Melt Pool Temperature and Microstructure". Journal of Manufacturing Science and Engineering, 24 de março de 2023, 1–31. http://dx.doi.org/10.1115/1.4062216.
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Abstract In this work, we developed a new additive manufacturing paradigm, coaxial wire-powder fed directed energy deposition (CWP-DED), to enable the fabrication of metals or composites with high manufacturing flexibility and efficiency. Herein, stainless steel (SS) 316L was selected as a representative material to validate the feasibility of CWP-DED process. Effects of feed rates on the melt pool thermodynamics during the CWP-DED process were investigated using experimental and analytical approaches. Thermal contributions of fed wire and powders to the melt pool were involved in the analytical model to predict the melt pool temperature. The experimental results from thermal imaging were also obtained for validation. Besides, we uncovered the evolution of solidification morphology and crystallographic texture with different combinations of wire and powder feed rates. Finally, the microhardness and tensile performance of different as-built parts were tested. The results showed that the powder feed rate played a more dominant role in determining the melt pool temperature than the wire feed rate. Melt pool temperature experienced an initial increase and then decrease with the powder feed rate. A fine microstructure was achieved at a low powder feed rate, producing higher microhardness and larger tensile strength. This paper revealed the relations among process, thermal variation, microstructures, and mechanical properties of as-built metallic parts to provide a fundamental understanding of this novel DED process.
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Gierth, Maximilian, Nils Michael, Philipp Henckell, Jan Reimann, Jörg Hildebrand e Jean Pierre Bergmann. "Influence of the temperature–time regime on the mechanical properties during the DED-Arc process of near-net-shape Ti-6Al-4 V components". Welding in the World, 11 de maio de 2023. http://dx.doi.org/10.1007/s40194-023-01513-7.
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AbstractIn a research project, the additive manufacturing process of components made of Ti-6Al-4 V using gas metal arc welding (GMAW), which is classified into the directed energy deposition–arc (DED-Arc) processes, was investigated. The project focused on the systematic development of economical additive build-up strategies and the analysis of the temperature–time regime during the build-up process, as well as the investigation of the resulting properties. A welding range diagram was created with recommendations for process settings for additive manufacturing with the controlled short circuit, as well as a presentation of possible defect patterns outside the range shown. For the fabrication of thick-walled structures, various build-up strategies were investigated by modifying the welding path and evaluated with regard to their suitability. Based on the results, additive structures were fabricated by varying the temperature–time regime in order to gain insights into selected geometrical, metallurgical, and mechanical properties. Different energy inputs per unit length, structure dimensions, and interpass temperatures (IPT) were used for this purpose. The research project provides comprehensive findings on the additive processing of the material Ti-6Al-4 V using metal inert gas welding, in particular with regard to the temperature–time regime and the resulting properties.
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Fullington, Durant, Linkan Bian e Wenmeng Tian. "Design De-identification of Thermal History for Collaborative Process-defect Modeling of Directed Energy Deposition Processes". Journal of Manufacturing Science and Engineering, 16 de dezembro de 2022, 1–40. http://dx.doi.org/10.1115/1.4056488.
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Abstract There is an urgent need for developing collaborative process-defect modeling in metal-based additive manufacturing (AM). This mainly stems from the high volume of training data needed to develop reliable machine learning models for anomaly detection. The requirements for large data are especially challenging for small-to-medium-manufacturers (SMMs), for whom collecting copious amounts of data is usually cost prohibitive. The objective of this research is to develop a secured data sharing mechanism for Directed Energy Deposition (DED) based AM without disclosing product design information, facilitating secured data aggregation for collaborative modeling. However, one major obstacle is the privacy concerns that arise from data sharing, since AM process data contains confidential design information. The proposed Adaptive Design De-identification for Additive Manufacturing (ADDAM) methodology integrates AM process knowledge into an adaptive de-identification procedure to mask the printing trajectory information in AM thermal history, which otherwise discloses major product design information. This adaptive approach applies a flexible data privacy level to each thermal image based on its similarity with the other images, facilitating better data utility preservation while protecting data privacy. A real-world case study was used to validate the proposed method based on the fabrication of two cylindrical parts using a DED process. These results are expressed as a pareto optimal solution, demonstrating significant improvements in privacy gain and minimal utility loss. The proposed method can facilitate privacy improvements of up to 30% with as little as 0% losses in dataset usability after de-identification.
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Nain, Vaibhav, Thierry Engel, Muriel Carin, Didier Boisselier e Lucas Seguy. "Development of an Elongated Ellipsoid Heat Source Model to Reduce Computation Time for Directed Energy Deposition Process". Frontiers in Materials 8 (8 de dezembro de 2021). http://dx.doi.org/10.3389/fmats.2021.747389.
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Directed Energy Deposition (DED) Additive Manufacturing process for metallic parts are becoming increasingly popular and widely accepted due to their potential of fabricating parts of large dimensions. The complex thermal cycles obtained due to the process physics results in accumulation of residual stress and distortion. However, to accurately model metal deposition heat transfer for large parts, numerical model leads to impractical computation time. In this work, a 3D transient finite element model with Quiet/Active element activation is developed for modeling metal deposition heat transfer analysis of DED process. To accurately model moving heat source, Goldak’s double ellipsoid model is implemented with small enough simulation time increment such that laser moves a distance of its radius over the course of each increment. Considering thin build-wall of Stainless Steel 316L fabricated with different process parameters, numerical results obtained with COMSOL 5.6 Multi-Physics software are successfully validated with experiment temperature data recorded at the substrate during the fabrication of 20 layers. To reduce the computation time, elongated ellipsoid heat input model that averages the heat source over its entire path is implemented. It has been found that by taking such large time increments, numerical model gives inaccurate results. Therefore, the track is divided into several sub-tracks, each of which is applied in one simulation increment. In this work, an investigation is done to find out the correct simulation time increment or sub-track size that leads to reduction in computation time (5–10 times) but still yields sufficiently accurate results (below 10% of relative error on temperature). Also, a Correction factor is introduced that further reduces computation error of elongated heat source. Finally, a new correlation is also established in finding out the correct time increment size and correction factor value to reduce the computation time yielding accurate results.
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Maulin, Maëva, Nicolas Estre, David Tisseur, Grégoire Kessedjian, Alix Sardet, Emmanuel Payan e Daniel Eck. "Défloutage de projections tomographiques industrielles hautes énergies à l’aide d’un réseau de neurones convolutifs". e-journal of nondestructive testing 28, n.º 9 (setembro de 2023). http://dx.doi.org/10.58286/28481.
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La fabrication additive, métallique en particulier, est en plein essor, mais les pièces ainsi produites peuvent présenter des défauts tels que des anomalies d'impression, de la rétention de poudre ou des fissures. Pour contrôler l'intégrité de ces pièces, la tomographie par transmission haute résolution reste la méthode de référence. Cependant, pour inspecter des pièces massives et fortement absorbantes, la tomographie haute énergie avec un accélérateur linéaire d'électrons est nécessaire. Le Laboratoire de Mesures Nucléaires du CEA IRESNE dispose d'un tomographe haute énergie et a souhaité améliorer la qualité des projections acquises en mettant en place des post-traitements numériques. Afin d’essayer de dépasser les performances des méthodes de restauration classiques, basées sur des algorithmes de déconvolution, une approche de post-traitement novatrice a été étudiée : la déconvolution de flou par réseaux de neurones convolutifs. Pour ce faire, un jeu de données d’images a tout d’abord été généré par simulation. Un réseau de neurones convolutifs, basé sur la structure du réseau SRCNN (Super-Resolution Convolutional Neural Network), a ensuite été adapté, entraîné et évalué. Chaque hyperparamètre du réseau a alors été spécialement optimisé. Enfin, ce réseau a été validé sur des tomographies à 9 MeV d’objets réels afin d’évaluer les performances finales obtenues, mais aussi comprendre les limitations de ce type d’approche. Le réseau de neurones convolutifs ainsi optimisé démontre de bonnes performances de défloutage tout en limitant l’amplification du bruit.
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Liu, Chunxin, Taras Oriekhov e Michael Fokine. "Investigation of glass bonding and multi-layer deposition during filament-based glass 3D printing". Frontiers in Materials 9 (25 de agosto de 2022). http://dx.doi.org/10.3389/fmats.2022.978861.
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Additive manufacturing of glass is an emerging technology that is foreseen to have a big impact on glass fabrication for innovative solutions within research, as well as for industrial applications. One approach is 3D printing using glass filaments. This technique is similar to directed energy deposition (DED) of metal wires using laser melting, which is highly versatile in printing complex structures. For glass, however, the technique is still at an early stage of development. Printing complex multi-layer structures have been challenging, often resulting in poor control of print geometry, excessive evaporation, as well as low repeatability. In this work we present a systematic study of filament-based 3D printing of silica-glass using CO2-laser heating. The study focuses on the bonding width (wetting) during first-layer printing onto fused quartz substrates and during multi-layer printing, i.e., layer-to-layer bonding. The main printing parameters that have been investigated include printing speed, filament feed rate, and incident laser power. Bonding widths from 17 to 221 µm are achieved with 196 µm diameter fused silica filaments in single line printing. Using experimentally determined printing parameters for such filament, 3D printed objects consisting of more than 100 layers were subsequently demonstrated. The results presented here provide an approach in glass 3D printing, using the filament-based technique, enabling highly complex glass structures to be fabricated.
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Singh, Aarti. "Recent Advancements in 3-D Printing in Medical Applications". INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 07, n.º 07 (27 de julho de 2023). http://dx.doi.org/10.55041/ijsrem24845.
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The field of three-dimensional (3D) printing has witnessed significant advancements in recent years, and its potential for revolutionizing medical applications is rapidly emerging. This review aims to provide an overview of the current state and scope of 3D printing in the medical field. The review begins by highlighting the various 3D printing technologies currently employed in healthcare settings, including stereolithography, selective laser sintering, fused deposition modeling, and inkjet printing. Each technology's advantages and limitations are discussed, shedding light on their suitability for different medical applications. Next, the review delves into the diverse range of medical applications where 3D printing has shown promise. These applications include the fabrication of patient-specific anatomical models for preoperative planning, surgical guides and tools, customized implants and prosthetics, tissue engineering scaffolds, and drug delivery systems. The potential benefits of using 3D printing in these areas, such as enhanced surgical accuracy, improved patient outcomes, reduced surgery time, and personalized medicine, are explored. Furthermore, the review addresses the challenges and limitations associated with implementing 3D printing in medical settings. These challenges include regulatory concerns, standardization of processes, material biocompatibility, cost-effectiveness, and scalability. The ongoing efforts to overcome these barriers and the future directions of 3D printing in medicine are also discussed. In conclusion, 3D printing holds immense potential for transforming various aspects of medical practice. While considerable progress has been made, there are still challenges to be addressed before widespread adoption can be achieved. With continued research and development, coupled with regulatory support and collaboration between academia, industry, and healthcare professionals, 3D printing is poised to International Journal of Scientific Research in Engineering and Management (IJSREM) Volume: 07 Issue: 07 | July - 2023 SJIF Rating: 8.176 ISSN: 2582-3930 © 2023, IJSREM | www.ijsrem.com DOI: 10.55041/IJSREM24845 | Page 2 make a substantial impact in the field of medicine, improving patient care and treatment outcomes. Key words: Additive manufacturing (AM); Bio-medical; Fused Deposition Modelling (FDM); Selective Laser Sintering (SLS); Stereolithography (SLA); Digital Light Processing (DLP); Binder Jetting; Material Jetting; Direct Energy Deposition (DED).