Статті в журналах: "Vacuum Arc Remelting (VAR)"

1

Campbell, John. "A Future for Vacuum Arc Remelting and Electroslag Remelting—A Critical Perspective." Metals 13, no. 10 (September 23, 2023): 1634. http://dx.doi.org/10.3390/met13101634.

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In the secondary metals refining processes, vacuum arc remelting (VAR) and electroslag remelting (ESR), the consumable electrode is commonly produced by vacuum induction melting (VIM) which employs the regrettably primitive casting technique of simply pouring into the open top of the mold. Despite the vacuum, the resulting oxidizing conditions and the immensely powerful turbulence accompanying the top-pouring of the electrode is now known to create a substantial density of serious cracks. The cracks in the cast electrode are bifilms (double oxide films), which in turn are proposed to be responsible for the major faults of the VAR ingot, including undetectable, horizontal macroscopic cracks, white spots (clean and dirty varieties) and in-fallen crown. The remedial action to solve all these issues at a stroke is the provision of a counter-gravity cast electrode, cast in air or vacuum, or provision of any similar electrode substantially free from bifilm defects. The ESR process is also described, explaining the reasons for its significantly reduced sensitivity to the top-poured VIM electrode, but indicating that with an improved electrode, this already nearly reliable process has the potential for perfect reliability. The target of this critical overview is an assessment of the potential of these secondary refining processes to produce, for the first time, effectively defect-free metals, metals we can trust.

2

Mucsi, C. S., Rubens Nunes de Faria Jr., E. Galego, and J. L. Rossi. "Consolidation of Compacted Zircaloy Chips via Vacuum Arc Melting - Analysis of the Electric Arc." Materials Science Forum 498-499 (November 2005): 258–63. http://dx.doi.org/10.4028/www.scientific.net/msf.498-499.258.

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The main objective of this work is to present the preliminary results on the analysis of the signals arising from the electrical arc, during the vacuum arc remelting of Zircaloy electrodes, aiming the automation of the fusion process. Zircaloy electrodes were made from compacted chips resultant of the machining of Zircaloy rods. The melts were performed in a prototype (vacuum arc remelting) VAR furnace under low pressure of argon and the arc was fed by a constant DC power source. Both filtered and unfiltered signals were recorded by means of a data acquisition system. The fast Fourier transforms FFT and autocorrelation integral were used as tools for data analysis. The result showed that the events occurring within the electric arc have a strong influence on the electric signals. The analysis allowed inferring that the VAR electric arc system has mainly a chaotic behaviour and sporadic periods of linear behaviour. The conclusion of this work is that a control system may be developed, based on the modelling of the non-linear behaviour of the arc, mainly chaotic. This may allow the achievement of an automatic control for the process and yield better quality products.

3

Shi, Zhiyue, Wenquan Cao, Chengjia Shang, and Xiaodan Zhang. "Effect of inclusion type on the rotating bending fatigue properties of a high carbon chromium bearing steel." IOP Conference Series: Materials Science and Engineering 1249, no. 1 (July 1, 2022): 012032. http://dx.doi.org/10.1088/1757-899x/1249/1/012032.

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Abstract The use of the double vacuum melting route (conventional second refining + vacuum arc refining, CSR+VAR) and the electroslag remelting route (vacuum induction melting + electroslag remelting, VIM+ESR)) has been investigated for the SAE52100 (100Cr6) bearing steel. The tensile properties, impact toughness, hardness and RCF life of the CSR+VAR steel and the steel prepared using the VIM+ESR route are similar. The number and size of TiN inclusions in the VIM+ESR steel are higher and larger than those in the CSR+VAR steel, providing an explanation for the observation of better fatigue properties for the CSR+VAR steel. Two major types of inclusions, magnesium aluminates/Al2O3-CaO-CaS and TiN, are located in different areas in a map of stress intensity factor versus rotatory bending fatigue cycles (NRBF ). The negative impact of TiN inclusions on fatigue properties are greater than those of magnesium aluminates/Al2O3-CaO-CaS inclusions.

4

Alam, M. K., S. L. Semiatin, and Z. Ali. "Thermal Stress Development During Vacuum Arc Remelting and Permanent Mold Casting of Ingots." Journal of Manufacturing Science and Engineering 120, no. 4 (November 1, 1998): 755–63. http://dx.doi.org/10.1115/1.2830216.

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The development of thermal stresses in ingots during the vacuum arc remelting (VAR) as well as specialized permanent mold casting (PMC) process was modeled via numerical solution of the two-dimensional, nonsteady-state heat conduction and stress equilibrium equations. The numerical analysis was carried out in conjunction with experimental studies of the mechanical properties and microstructure of a cracked VAR titanium aluminide ingot. Numerical solutions were obtained for different values of ingot diameter, crucible-ingot interface heat transfer coefficients, and lengths of the melted-and-resolidified ingot. For both VAR and PMC, model predictions revealed that the maximum tensile thermal stresses are developed at the bottom of the ingot; the magnitude of such stresses increases with ingot diameter and the magnitude of the interface heat transfer coefficients. The microstructural analysis of a cracked ingot indicated that the thermal cracking occurred in the temperature range where the alloy has very little ductility. The predicted development of large tensile stresses correlates well with observations of thermal cracking during VAR of near-gamma titanium aluminide alloy ingots. By contrast, the predicted thermal stresses developed during PMC are lower, thus suggesting an attractive alternative to VAR to obtain sound, crack-free ingots.

5

Konopatsky, Anton S., Yulia S. Zhukova, and Mikhail R. Filonov. "Production and Quality Assessment of Superelastic Ti-Nb-Based Alloys for Medical Application." Advanced Materials Research 1040 (September 2014): 130–36. http://dx.doi.org/10.4028/www.scientific.net/amr.1040.130.

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Superelastic biocompatible metallic materials Ti-22Nb-6Zr and Ti-22Nb-3Ta-3Zr (at %) were produced. Vacuum arc remelting (VAR) with manual control allowed to produce high‑purity alloys. X-ray fluorescence spectrometry (XRF) results showed that one remelt was not enough to obtain homogeneous Ti-Nb-Ta-Zr ingot. Ti-Nb-Zr and Ti-Nb-Ta-Zr alloys were remelted 3 times and turned upside down after each remelting. Scanning electron microscopy (SEM) with micro X‑ray spectral analysis showed that chemical composition of the alloys coincided with nominal chemical composition. SEM results also showed that the alloys were mostly homogeneous. Recommendations for optimization of VAR in terms of producing high-purity homogeneous superelastic titanium alloys were elaborated.

6

Karimi-Sibaki, E., A. Kharicha, M. Wu, A. Ludwig, and J. Bohacek. "A Parametric Study of the Vacuum Arc Remelting (VAR) Process: Effects of Arc Radius, Side-Arcing, and Gas Cooling." Metallurgical and Materials Transactions B 51, no. 1 (October 29, 2019): 222–35. http://dx.doi.org/10.1007/s11663-019-01719-5.

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Abstract Main modeling challenges for vacuum arc remelting (VAR) are briefly highlighted concerning various involving phenomena during the process such as formation and movement of cathode spots on the surface of electrode, the vacuum plasma, side-arcing, the thermal radiation in the vacuum region, magnetohydrodynamics (MHD) in the molten pool, melting of the electrode, and solidification of the ingot. A numerical model is proposed to investigate the influence of several decisive parameters such as arc mode (diffusive or constricted), amount of side-arcing, and gas cooling of shrinkage gap at mold–ingot interface on the solidification behavior of a Titanium-based (Ti-6Al-4V) VAR ingot. The electromagnetic and thermal fields are solved in the entire system including the electrode, vacuum plasma, ingot, and mold. The flow field in the molten pool and the solidification pool profile are computed. The depth of molten pool decreases as the radius of arc increases. With the decreasing amount of side-arcing, the depth of the molten pool increases. Furthermore, gas cooling fairly improves the internal quality of ingot (shallow pool depth) without affecting hydrodynamics in the molten pool. Modeling results are validated against an experiment.

7

Descotes, Vincent, Thibault Quatravaux, Jean-Pierre Bellot, Sylvain Witzke, and Alain Jardy. "Titanium Nitride (TiN) Germination and Growth during Vacuum Arc Remelting of a Maraging Steel." Metals 10, no. 4 (April 22, 2020): 541. http://dx.doi.org/10.3390/met10040541.

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During the processing of maraging steels, Titanium easily combines with Nitrogen to form nitride inclusions, known to be deleterious for fatigue properties of the alloy. According to thermodynamic calculations, the precipitation occurs during solidification of the vacuum arc remelted (VAR) ingot. A coupled model of titanium nitride (TiN) inclusion precipitation and vacuum remelting has been set-up to study the inclusion cleanliness of the ingot. The nitrogen content, nuclei numeral density and solidification time appear as the key factors which control the inclusion size.

8

YUAN, LANG, GEORGI DJAMBAZOV, PETER D. LEE, and KOULIS PERICLEOUS. "MULTISCALE MODELING OF THE VACUUM ARC REMELTING PROCESS FOR THE PREDICTION ON MICROSTRUCTURE FORMATION." International Journal of Modern Physics B 23, no. 06n07 (March 20, 2009): 1584–90. http://dx.doi.org/10.1142/s0217979209061305.

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The final solidification structures of Vacuum Arc Remelting (VAR) ingots depend on the temperature distribution and fluid motion within the molten pool. In this paper, a three-dimensional multi-physics macroscale model for VAR is developed, based on the modular CFD software PHYSICA. This model is used to provide estimates of process parameters and to study complex physical phenomena, such as liquid metal flow with turbulence, heat transfer, solidification, and magnetohydrodynamics in the VAR process. The macromodel is coupled to a microscale solidification model. The micromodel combines stochastic nucleation and a modified decentred square/octahedron method to describe dendritic growth with a finite difference computation of solute diffusion. The resulting multiscale model allows prediction of the formation of microstructures in the solidifying mushy zone. This gives a better understanding of the whole VAR process from operational conditions to final ingot microstructures, as well as an essential first step in defect prediction.

9

Lv, Guo Yun, and Shui Xian Hu. "Research on Vacuum Consumable Arc Remelting Furnace Control System with Drop Short Pulses Testing." Advanced Materials Research 605-607 (December 2012): 1670–74. http://dx.doi.org/10.4028/www.scientific.net/amr.605-607.1670.

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Stable and Reliable automatic control system of Vacuum Consumable Arc Remelting (VAR) furnace is the key to smelt successfully special alloy metal and high temperature alloy metal, which is related to special properties of remelting ingot directly. This paper makes a deep study for drop short pulse testing and controlling system, and digital signal processing is used to obtain drop short pulse value with different frequency ranges. Firstly, basic theory analysis of drop short pulse measuring and controlling is researched. Secondly, high-speed digital signal processing technology is adopted to sample furnace voltage signal real-timely, band pass filter group is designed directly to process and calculate the amount of drop short pulses in different frequency ranges, Finally, the relationship between drop short pulse frequency and special alloy materials is analyzed, fuzzy PID control method is used to adjust electrode gap and control arc length. Field experiment results show the effectiveness of the whole drop short pulse testing and controlling system.

10

Geanta, Victor, Ionelia Voiculescu, Radu Stefanoiu, and Elena Roxana Rusu. "Stainless Steels with Biocompatible Properties for Medical Devices." Key Engineering Materials 583 (September 2013): 9–15. http://dx.doi.org/10.4028/www.scientific.net/kem.583.9.

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Stainless steels, commercial as well as with special properties, are the principal metallic materials used for medical devices manufacturing. Stainless steels for medical devices should have superior mechanical properties, as: hardness, wear resistance, tensile strength, elongation, fracture toughness, creep resistance etc. This paper aims to present experimental researches regarding the obtaining in vacuum arc remelting device (VAR) of austenitic and martensitic stainless steels and their characterization from microstructure and microhardness point of view.

11

Doridot, Emiliane, Stéphane Hans, Alain Jardy, and Jean-Pierre Bellot. "Industrial applications of modelling tools to simulate the PAMCHR casting and VAR process for Ti64." MATEC Web of Conferences 321 (2020): 10011. http://dx.doi.org/10.1051/matecconf/202032110011.

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The PAMCHR (Plasma Arc Melting Cold Hearth Refining) process followed by a VAR (Vacuum Arc Remelting) melting is used to recycle Ti64 scrap for aeronautical applications. The produced ingot quality is linked to the quality of charging materials and to numerous operating parameters. Ecotitanium (a company created by UKAD, a joint-venture between Aubert & Duval and UKTMP, ADEME and Crédit Agricole Centre France) launched a program with the Institut Jean Lamour dedicated to the development of specific modelling tools in order to get a better understanding of operating parameters effect on the final ingot quality. A model of the PAMCHR casting was developed and used to describe the heat transfer, liquid metal flow and alloying elements behavior during mixing in the liquid pool followed by segregation during solidification. The effect of PAMCHR electrode composition on the final VAR ingot composition is also studied using the SOLAR VAR model. Model validation by comparison with industrial ingots is presented with some examples of operating parameters sensitivity study.

12

Williamson, Rodney L., and Joseph J. Beaman. "Modern Control Theory Applied to Remelting of Superalloys." Materials Science Forum 706-709 (January 2012): 2484–89. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.2484.

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Over the past several years we have worked to develop tools to improve the quality of superalloy ingots produced by vacuum arc remelting (VAR) and electroslag remelting (ESR). Part of this work has focused on developing model-based process controllers that employ predictive, dynamic, low-order electrode melting and ingot solidification models to estimate important process variables. These estimated variables (some of which are not subject to measurement) are used for feedback and to evaluate the health of the processes. Modern controllers are capable of detecting and flagging various process upsets and sensor failures, and can take remedial action under some circumstances. Model-based variable estimates are continuously compared with measurements when available, and the residuals are used to correct the next generation of estimates. This technology has led to improved VAR and ESR melt rate controllers and is currently being used to develop a VAR ingot solidification controller. A first generation ingot pool depth controller has been tested on a laboratory VAR furnace and the results are very encouraging. In this test, a 152 mm diameter Alloy 718 electrode was remelted into a 216 mm diameter ingot, but the technology is easily scaled to industrial sizes. Successful development of this technology could allow for melting at higher powers without the formation of channel segregates (freckles) by stabilizing the ingot solidification zone. It may also allow for the production of larger diameter VAR superalloy ingots than is possible to produce with the current generation of VAR controllers for the same reason.

13

Lv, Guo Yun, and Shui Xian Hu. "Research on Vacuum Consumable Arc Remelting Furnace Drop Testing System for Thyristor Power Supply." Applied Mechanics and Materials 268-270 (December 2012): 1494–98. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.1494.

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Stable and reliable automatic control system of Vacuum Consumable Arc Remelting (VAR) furnace with thyristor power supply is the key to smelt successfully special alloy metal and high temperature alloy metal, which is related to special properties of remelting ingot directly, however, it is key problem to test the drop pulse for thyristor supply. This paper makes a deep study for drop short pulse testing system on AVR with thyristor power supply, and digital signal processing is used to obtain drop short pulse value with different frequency ranges. According to the specification of thyristor power supply, firstly, basic theory analysis of drop short pulse measuring is researched. Secondly, high-speed digital signal processing technology is adopted to sample furnace voltage signal real-timely, trap filter group is designed to remove the multiple order harmonic, and band pass filter group is designed directly to process and calculate the amount of drop short pulses in different frequency ranges, finally, the material parameters which impact on drop short frequency. Field experiment results show the effectiveness of the whole drop short pulse testing system.

14

Cui, Jiajun, Baokuan Li, Zhongqiu Liu, Fengsheng Qi, Beijiang Zhang, and Ji Zhang. "Numerical Investigation of Segregation Evolution during the Vacuum Arc Remelting Process of Ni-Based Superalloy Ingots." Metals 11, no. 12 (December 17, 2021): 2046. http://dx.doi.org/10.3390/met11122046.

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Segregation defects greatly affect the service performance and working life of castings during the vacuum arc remelting (VAR) process. However, the corresponding research on the prediction of segregation defects is still not comprehensive. Through considering the influence of water-cooled crucible on the electromagnetic field inside an ingot, a full-scale model for the comprehensive prediction of freckles and macrosegregation defects during the VAR process is developed in this paper. The macroscopic solute transport phenomenon and the segregation behavior of Ni-5.8 wt% Al-15.2 wt% Ta alloy are predicted. The results indicate that the freckles are mainly concentrated in the lower region of the ingot. With the growth of the ingot, the solute enrichment channels gradually develop into solute enrichment regions, and the channel segregation evolves into macrosegregation. The Lorentz force mainly affects the flow pattern at the top of the molten pool, while the complex flow of multiple vortices is dominated by thermosolutal buoyancy. The maximum and minimum relative segregation ratio inside the ingot can reach 290% and −90%, respectively, and the positive segregation region accounts for about 79% of the total volume. This paper provides a new perspective for understanding the segregation behavior inside the ingot by studying the segregation evolution during the VAR process.

15

Delzant, Pierre-Olivier, Pierre Chapelle, Alain Jardy, Alexey Matveichev, and Yvon Millet. "Impact of a Transient and Asymmetrical Distribution of the Electric Arc on the Solidification Conditions of the Ingot in the VAR Process." Metals 12, no. 3 (March 16, 2022): 500. http://dx.doi.org/10.3390/met12030500.

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Vacuum Arc Remelting is an important method of processing reactive and refractory liquid metal alloys, including titanium and zirconium alloys. Recent measurements of the electric arc dynamics under the presence of a time-varying magnetic field during an industrial melt of a Ti64 alloy provided evidence of the existence of an ensemble arc motion. Such motion is responsible for transient and non-axisymmetric inputs of electric current and energy at the top surface of the remelted ingot. The present work is an attempt to evaluate, using a simplified numerical simulation approach, to what extent the solidification conditions of the VAR ingot and, consequently, the quality of the final product, may be affected by this phenomenon. The reported results indicate that, under the worst case conditions, the relative vanadium segregation in the solidified ingot can reach values as high as 12.5%.

16

Shang, Jinjin, Yongsheng He, Ce Yang, Ming Wu, Wenzhong Luo, and Kaixuan Wang. "Freckles pattern and microstructure feature of Nb-Ti alloy produced by vacuum arc remelting." MATEC Web of Conferences 321 (2020): 10009. http://dx.doi.org/10.1051/matecconf/202032110009.

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Nb-Ti alloys are normally produced by vacuum arc remelting process. Due to inadequate processing parameters, freckles can be observed in macroetched ingots. In the present work, visual, chemical, metallographic, and X-ray are presented which establish the appearance, composition, microstructure differences between freckle regions and normal regions. It has been observed that in freckles parallel to the ingot axis, the Ti content is up to 53wt%, 7wt% higher than normal regions. It is also shown that a lot of precipitation phases appeared in freckle regions, because of the thermosolutal convection in the mushy zone. The Rayleigh number, which recommended as a criterion for freckle initiation, has been calculated that using a VAR melting software. Based on the experimental results and simulation results, it is concluded that freckles can be influenced by processing parameters, and freckles in Nb-Ti alloy can be eliminated by matching appropriate processing parameters.

17

Zhu, Bin, Xiang Yi Xue, Hong Chao Kou, Cong Xiao, and Jin Shan Li. "Macroscale Modeling of Multi-Physics Fields during Vacuum Arc Remelting of Ti-6Al-4V." Materials Science Forum 789 (April 2014): 603–7. http://dx.doi.org/10.4028/www.scientific.net/msf.789.603.

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A 3-D finite element model has been established using ANSYS12.0 software to simulate multi-physical interaction behavior during the Vacuum Arc Remelting (VAR) of 740-mm-diameter ingots of Ti-6Al-4V. The models of temperature field, electromagnetic and flow field were combined by progressive method. The effect of thermal contraction was considered in the simulation of temperature field and electromagnetic by setting a thin layer with different nature parameters at the ingot-crucible interface. The model results demonstrate the distributions of temperature, Lorenz force and flow velocity, and the influence of water cooling conditions, melting current and other process parameters. The molten pool behavior is mostly dominated by buoyancy force under circumstances in this case. The increase of the melting current results in an increase of the pool depth and melting rate, and causes great change of the molten pool profile, while the influence of the water cooling conditions is ignored.

18

Hua, Zhengli, Wenzhong Luo, Tao He, Qiang Lei, Longzhou Wang, and Xianghong Liu. "Effect of Melting Interruption on Composition and Microstructure of BT22 Ingot in VAR." MATEC Web of Conferences 321 (2020): 10008. http://dx.doi.org/10.1051/matecconf/202032110008.

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BT22 ingot was remelted by vacuum arc remelting (VAR) furnace with a melting rate of 20kg/min. The power of VA R was interrupted for five minutes when the weight of the remelted ingot is approximately 4000 kg. The melting process was then resumed at the same melting rate after the five minutes interruption. Optical microscopy (OM), inductively coupled plasma-mass spectrometry (ICP-MS) and electron probe micro analyzer (EPMA) were utilized to analyze the microstructure, composition and distribution of elements. No significant microstructural difference was oberved at the remelting interrupted region. The variation of Al, Mo, V, Cr, Fe contents between the melting interruption region and normal region is within 0.23 wt%. The distribution of elements in equiaxed grains of the melting interruption region and the normal regions were compared by EPMA analysis. The contents of Al, V, Fe and Cr increase from the center of equiaxed grains to their grain boundaries. The content of Mo decreases from the center of equiaxed grains to their grain boundaries. The trend of element content in the normal region is similar to that of the melting interrupted region. Key words: BT22; ingot; composition; microstructure

19

Beaman, Joseph, and Felipe Lopez. "Emerging Nexis of Cyber, Modeling, and Estimation in Advanced Manufacturing." Mechanical Engineering 136, no. 12 (December 1, 2014): S8—S15. http://dx.doi.org/10.1115/1.2014-dec-6.

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This article describes opportunities for exploiting cyber, modeling, and estimation technical areas for advanced manufacturing in small lots. In particular, Cyber Enabled Manufacturing Systems (CeMs) for small lot manufacturing that incorporates a model of the process directly into the control algorithm are presented and discussed. The model enables the manufacturing monitoring and control algorithm to accommodate changing conditions without extensive additional experiments. One of the manufacturing processes currently being studied with this methodology is Vacuum Arc Remelting (VAR). Similar to Additive Manufacturing, VAR is a small lot, high-value manufacturing process. There is great opportunity for the control community to have a major impact on advanced manufacturing. This includes increasing the performance of mature manufacturing processes such as VAR or developing the critical control of emerging manufacturing processes like 3D printing. This opportunity is especially timely because of a nexus of multi-physics simulation software, modern estimation methods, and real-time computer architecture and hardware.

20

Yefanov, V. S., O. V. Ovchynnykov, O. A. Dzhuhan, S. M. Tkachenko, and V. S. Zhdan. "Improvement of the technology of melting ingots of nickel based alloys by vacuum arc remelting (VAR)." Physical Metallurgy and Heat Treatment of Metals, no. 3 (July 15, 2019): 42–48. http://dx.doi.org/10.30838/j.pmhtm.2413.250619.45.321.

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21

Fazakas, Eva, Bela Varga, Victor Geantă, Tibor Berecz, Péter Jenei, Ionelia Voiculescu, Mihaela Coșniță, and Radu Ștefănoiu. "Microstructure, Thermal, and Corrosion Behavior of the AlAgCuNiSnTi Equiatomic Multicomponent Alloy." Materials 12, no. 6 (March 20, 2019): 926. http://dx.doi.org/10.3390/ma12060926.

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The paper presents the microstructure and corrosion behavior of an AlTiNiCuAgSn new equiatomic multicomponent alloy. The alloy was obtained using the vacuum arc remelting (VAR) technique in MRF-ABJ900 equipment. The microstructural analysis was performed by optical and scanning electron microscopy (SEM microscope, SEM-EDS) and the phase transformations were highlighted by dilatometric analysis and differential thermal analysis (DTA). The results show that the as-cast alloy microstructure is three-phase, with an average microhardness of 487 HV0.1/15. The obtained alloy could be included in the group of compositionally complex alloys (CCA). The corrosion resistance was studied using the potentiodynamic method in saline solution with 3.5% NaCl. Considering the high corrosion resistance, the obtained alloy can be used for surface coating applications.

22

Qu, Heng Lei, Yong Qing Zhao, Zhi Shou Zhu, Hui Li, Liang Feng, Lian Zhou, and Ming Qiang Li. "Preliminary Research on a New Ultra-High Strength Titanium Alloy." Materials Science Forum 747-748 (February 2013): 818–22. http://dx.doi.org/10.4028/www.scientific.net/msf.747-748.818.

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Some research results are introduced briefly in this paper. A new kind of titanium alloy was designed based on nine elements system, which belongs to (a+b) type. Bars with diameter of 14 mm were produced via Vacuum Arc Remelting (VAR) melting and conventional forging and rolling facilities. Influence of alloy elements contents and heat treatments on microstructure and mechanical properties of the new alloy were studied. The results show that Ultimate Tensile Strength (UTS) is about 1200~1700MPa and Elongation (EL) is normally less than 5% at R.T., though Electron Beam (EB) welding can be proceeded, but the toughness of the alloy is poor at R.T.High temperature (HT) short-term strength of the alloy is also acceptable up to 600. Based on the above performances, the new material can be applied in the corresponding circumstances.

23

Descotes, V., J.-P. Bellot, V. Perrin-Guérin, S. Witzke, and A. Jardy. "Titanium nitride (TiN) precipitation in a maraging steel during the vacuum arc remelting (VAR) process - Inclusions characterization and modeling." IOP Conference Series: Materials Science and Engineering 143 (July 2016): 012013. http://dx.doi.org/10.1088/1757-899x/143/1/012013.

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Mucsi, Cristiano Stefano, L. A. M. dos Reis, Maurilio Pereira Gomes, L. A. T. Pereira, and Jesualdo Luiz Rossi. "Study on the Viability of the Recycling by Electric Arc Melting of Zirconium Alloys Scraps Aiming the Scalability of the Process." Materials Science Forum 930 (September 2018): 495–500. http://dx.doi.org/10.4028/www.scientific.net/msf.930.495.

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Turning chips of zirconium alloys are produced in large quantities during the machining of alloy rods for the fabrication of the end plugs for the Pressurized Water Reactor (PWR) fuel elements parts of Angra II nuclear reactor (Brazil – Rio de Janeiro). This paper presents a study on the search for an efficient way for the cleaning, quality control and Vacuum Arc Remelting (VAR) of pressed zirconium alloys chips to produce a material viable to be used in the production of the fuel rod end plugs. The process starts with cutting oil clean out. The first step in this process consists in soaking a bunch of chips in clean water, to remove soluble cutting oils, followed by an alkaline degreasing bath and a wash with a high-pressure flow of water. Drying is performed by a flux of warm air. The oil free chips are then subjected to a magnet in order to detect and collect any magnetic material, essentially ferrous, that may be present in the original chips. Samples of the material are collected and then melted in a small non consumable electrode vacuum arc furnace for evaluation by Energy Dispersive X-ray Fluorescence Spectrometry (EDXRFS) in order to define the quality of the chips. The next step consists in the 15 ton hydraulic pressing the chips in a die with 40 mm square section and 500 mm long, producing an electrode with 20% of the Zircaloy bulk density. The electrode was finally melted in a laboratory scale modified VAR furnace located at the CCTM–IPEN, producing 0.8 kg ingots. The authors conclude that the samples obtained from the fuel element industry can be melting in a VAR furnace, modified to accommodate low density electrodes, allowing a reduction up to 40 times the original storage volume, however, it is necessary to remelt the ingots to correct their composition in order to recycle the original zirconium alloys chips. in a process to reduce volume and allow the reutilization of valuable Zircaloy scraps.

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Mohri, Maryam, and Mahmud Nili Ahmadabadi. "Estimation of Thickness Ratio of Bi-Layer TiNi to Enhance Shape Memory Behavior." Advanced Materials Research 428 (January 2012): 141–46. http://dx.doi.org/10.4028/www.scientific.net/amr.428.141.

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Shape memory thin films deposited by sputtering are attractive candidates for micro-electro-mechanical-system (MEMS) because of their large deformation and strong recovery force. In the present study Ni-Ti thin films have been deposited on NaCl substrates by DC magnetron sputtering source fitted with an 80mm diameter alloy target. In order to obtain a variety of film compositions, several discs of alloy target, which prepared in vacuum arc remelting (VAR), were used. Three types of thin films have been deposited; Ti and Ni-rich thin films were separately deposited on NaCl substrate and also a composite layer of Ni45Ti50Cu5 and Ni-rich. The as deposited Ni-Ti thin films were crystallized to change the amorphous structure to a nanostructured material to characterize shape memory and superelastic behaviors. The effect of composition on film structure and mechanical behavior was studied by using X-ray diffraction (XRD) and nanoindentation. The results of thin films behavior were used to calculate the thickness ratio of be-layer composite NiTi to obtain enhanced shape memory behavior.

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Nunes, Aline Raquel Vieira, Sinara Borborema, Leonardo Sales Araújo, Luiz Henrique de de Almeida та Michael J. Kaufman. "Production of a Novel Biomedical β-Type Titanium Alloy Ti-23.6Nb-5.1Mo-6.7Zr with Low Young’s Modulus". Metals 12, № 10 (24 вересня 2022): 1588. http://dx.doi.org/10.3390/met12101588.

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Metastable β titanium alloys are developed for biomedical applications due to their low Young’s moduli and functional properties. These alloys can be fitted to different parts of orthopedic implants through thermomechanical processing and chemical composition control. This study aimed to produce, process, and characterize a new metastable β titanium Ti-23.6Nb-5.1Mo-6.7Zr alloy on a semi-industrial scale for orthopedic implant manufacturing, and to discuss the influence of the cold rolling and transformed phases during aging in the microstructure and mechanical properties. This alloy was produced in a vacuum arc remelting furnace (VAR) and thermomechanically processed under different conditions. The samples were characterized by X-ray diffractometry, optical, and scanning electron microscopy, and Young’s modulus (YM) and Vickers Hardness (HV) tests. Among other processing conditions, the sample that was 50% cold rolled after solution treatment, which resulted in a microstructure with β and α″ phases, had the lowest YM (~57 GPa), and the sample aged at 300 °C for 2 h had the highest HV/YM ratio (5.42). The new alloy produced in this work, processed by different routes, showed better mechanical properties than most recently developed metastable Ti-β Alloys.

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Qu, Jinglong, Shufeng Yang, Zhengyang Chen, Jinhui Du, Jingshe Li, and Di Wang. "Effect of Turning Amount on Metallurgical Qualities and Mechanical Properties of GH4169 Superalloy." Materials 12, no. 11 (June 7, 2019): 1852. http://dx.doi.org/10.3390/ma12111852.

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The determination of an appropriate amount of turning for superalloy ingot surfaces, in a scientific and reasonable manner, is vital to the improvement of the metallurgical quality and comprehensive performance of superalloy ingots. In the present study, scanning electron microscopy with energy-dispersive spectroscopy, a high-temperature testing machine, a Brinell hardness tester and the Image-Pro Plus software were used to analyze and compare the types and amounts of inclusions, the average area of the (Al,Mg)O inclusions, and the mechanical properties of points at different distances from the edge of the GH4169 superalloy vacuum arc remelting (VAR) ingot edge. The effects of the amount of turning to which the superalloy is subjected, the metallurgical qualities, and the mechanical properties were systematically studied. The results showed that the five inclusion types did not change as the sampling locations moved away from the ingot edge, but the amount of inclusions and the average area of the (Al,Mg)O inclusions first decreased and then stabilized. Similarly, the tensile strength, elongation, section shrinkage, hardness, and fatigue life first increased and then stabilized. Finally, this experiment tentatively determined that an appropriate amount of turning for a GH4169 superalloy ingot is 36–48 mm.

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Hussein, Saja M., Khansaa D. Salman, and Ahmed A. Hussein. "Phase Transformations, Microstructure and Shape Memory Effect of NiTiAg Alloy with Different Atomic Percentages (at. % Ag) Manufactured by Casting Method." Engineering and Technology Journal 39, no. 4A (April 25, 2021): 543–51. http://dx.doi.org/10.30684/etj.v39i4a.1833.

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In this paper, shape memory alloys (SMAs) (NiTi-based) have been manufactured by casting with a different atomic percentage of a silver element (0, 1, 2 and 3 at. % Ag) using a Vacuum Arc Remelting (VAR) furnace. The silver element is added to the binary alloys due to its excellent properties such as (anti-corrosion, anti-bacterial and high electrical conductivity), which make these alloys using in wider applications. These alloys with different atomic percentages (Ni55Ti45Ag0, Ni55Ti44Ag1, Ni55Ti43Ag2 and Ni55Ti42Ag3) have been manufactured. The successful manufacturing process has been achieved and proved via examinations and tests. The FESEM microscopic examinations show that the silver element has been distributed uniformly and homogeneously in the NiTi matrix. Moreover, the emergence of austenite phase, martensite phase and little amount impurities. Regarding the XRD examination, showed that there is an increase in the number of peaks of Ag phase with an increase in the atomic percentage of the silver element, as well to emergence of phase (Ti2Ni) upon heating, phase (Ti 002) upon cooling, and phase (Ni4Ti3) is not desired. The starting and finishing of the phase transformations have been determined for all samples by the DSC test. The Shape Memory Effect (SME) for the alloy (Ni50Ti42Ag3) is measured to be about 89.99%.

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Jimenez-Marcos, Cristina, Julia Claudia Mirza-Rosca, Madalina Simona Baltatu, and Petrica Vizureanu. "Experimental Research on New Developed Titanium Alloys for Biomedical Applications." Bioengineering 9, no. 11 (November 12, 2022): 686. http://dx.doi.org/10.3390/bioengineering9110686.

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The mechanical properties and electrochemical behavior of two new titanium alloys, Ti20Mo7Zr and Ti20Mo7Zr0.5Si, are investigated in this paper. The alloys have been manufactured by vacuum arc remelting (VAR) technique and studied to determine their microstructure, corrosion behavior, and mechanical properties. Metallographic observations and quantitative microanalysis by optical microscopy, scanning electron microscopy SEM, and energy dispersive X-rays spectroscopy EDX were performed. Data about the three-point bending test and microhardness are presented. For electrochemical properties, three different environments were used: Ringer solution at 25 °C, Ringer solution at 40 °C simulating fever condition, and 3.5% NaCl solution. Metallographic investigation revealed the biphasic and dendritic structure of both samples when the procedures were performed. Electrochemical testing in body simulation fluid, fever conditions, and saline medium showed that the lower the proportion of silicon in the samples, the higher the corrosion resistance. The formation of a titanium oxide layer on the surface of both samples was noticed using quantitative EDX analysis. The three-point bending test for the two samples revealed that the presence of silicon decreases the modulus of elasticity; the surface of the samples displayed soft and hard phases in the microhardness test. Electrochemical impedance spectroscopy (EIS) measurements were carried out at different potentials, and the obtained spectra exhibit a two-time constant system, attesting double-layer passive film on the samples.

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Geanta, Victor, Ionelia Voiculescu, Ioan Milosan, Bogdan Istrate, and Ileana Mariana Mates. "Chemical Composition Influence on Microhardness, Microstructure and Phase Morphology of AlxCrFeCoNi High Entropy Alloys." Revista de Chimie 69, no. 4 (May 15, 2018): 798–801. http://dx.doi.org/10.37358/rc.18.4.6203.

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The AlCrFeCoNi high entropy alloy exhibits unexpected properties that can be obtained after mixing five different elements, which could not be obtained from any one independent element. The difference to conventional alloys is that these alloys may have, at the same time, both hardness and plasticity, can be used in severe impact applications. In order to study the influence of aluminum content on the microhardness and microstructure of the high entropy alloys AlxCrFeCoNi (x: atomic ratio, x= 0.2 to 2.0) nine types of samples were obtained as mini-sized ingots (50x15x9.5 mm and 40 g weight). The mini-ingots were obtained using arc melt casting process in a vacuum arc remelting device (VAR MRF ABJ 900). The influence of the chemical elements on the microstructure, phases morphology and microhardness of AlxCrFeCoNi system was studied. The results have confirmed that mechanical properties could be greatly adjusted by the chemical composition change. The main element that influences the microhardness of the analyzed system is aluminum, due to the formation of Al-Fe compounds with high hardness. Increasing the aluminum content in the alloy to values greater than 1.8 ... 2 at.% contribute to the increase of hardness and also to the embrittlement thereof. Other elements like Cr, Fe, Co and Ni can contribute to mitigate increasing the hardness of the alloy. The type of phases formed in high entropy alloy are dependent to the aluminum concentration. So, depending on of aluminium content, different phases are obtained, like FCC for low Al content, mixture of FCC and BCC for about 2.5 %Al and BCC for high Al content. The crystallite size depends on the chemical composition and increase with the aluminium content.

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Kelkar, K., and A. Mitchell. "Beta Fleck formation in Titanium Alloys." MATEC Web of Conferences 321 (2020): 10001. http://dx.doi.org/10.1051/matecconf/202032110001.

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Beta fleck is a troublesome segregation defect in many titanium alloys. It has previously been investigated by several authors and appears to have two formation mechanisms, one similar to that of “freckle” in steels and nickel-base alloys, the other arising in the “crystal rain” effect seen in conventional steel ingots. The freckle defect has been extensively studied and several theories developed to account for its formation in both remelted ingots and directional castings. In this work we compare the findings of investigations into the nickel-base freckle formation mechanism to similar conditions in the vacuum arc remelting of titanium alloys. We find that there are strong similarities between the beta fleck formation conditions and the parameters related to the Rayleigh Number criterion for freckle formation. In particular, the dendritic solidification parameters and the density dependence on segregation coefficients both fit well with the conditions proposed to characterise freckle formation. The second formation mechanism arises in the columnar to equiax transition in solidification. The condition for the avoidance of the defect in the two cases is the shown to be the same, namely the use of a very low VAR melting rate, but that it is unlikely to be 100% successful in preventing defect formation. We propose that the techniques presently in use for alloy development in the superalloy field through optimising the composition for minimum sensitivity to freckle formation should be applied to the formulation of future titanium alloys; also that attention should be paid to developing the PAM process to provide suitable solidification conditions for defect absence in a final ingot.

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Laszlo, Edwin Alexandru, Doina Crăciun, Gabriela Dorcioman, Gabriel Crăciun, Victor Geantă, Ionelia Voiculescu, Daniel Cristea, and Valentin Crăciun. "Characteristics of Thin High Entropy Alloy Films Grown by Pulsed Laser Deposition." Coatings 12, no. 8 (August 18, 2022): 1211. http://dx.doi.org/10.3390/coatings12081211.

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Starting from solid-solutions (SS) of AlCoCrFeNix high-entropy alloys (HEAs) that have been produced with high purity constituent elements by vacuum arc remelting (VAR) method varying the nickel molar ratio x from 0.2 to 2.0, we investigated the synthesis of protective thin films of HEAs and high-entropy nitrides (HENs) with the aid of the pulsed laser deposition (PLD) system. The structure of all ten available bulk targets have been examined by means of X-Ray Diffraction (XRD), as well as their elemental composition by means of energy dispersion X-ray spectroscopy (EDS). Three targets with nickel molar composition x = 0.4, 1.2 and 2.0 corresponding to BCC, mixed BCC and FCC, and finally FCC structures were used for thin film depositions using a KrF excimer laser. The depositions were performed in residual low vacuum (10−7 mbar) and under N2 (10−4 mbar) at room temperature (RT~25 °C) on Si and glass substrates. The deposited films’ structure was investigated using grazing incidence XRD, their surface morphology, thickness and elemental composition by scanning electron microscopy (SEM), EDS and X-ray photoelectron spectroscopy (XPS), respectively. A homemade four-point probe (4PP) set-up was applied to determine layers electrical resistance. Besides, a Nanoindentation (NI) was employed to test films’ mechanical properties. XRD results showed that all deposited films, regardless of the initial structure of targets, were a mixture of FCC and BCC structures. Additionally, the quantitative and qualitative EDS and XPS results showed that the elemental composition of films was rather close to that of the targets. The depositions under an N2 atmosphere resulted in the inclusion of several percentage nitrogen atoms in a metallic nitride type compound into films, which may explain their higher electrical resistivity. The Young’s modulus, nanohardness and friction coefficient values showed that the deposited films present good mechanical properties and could be used as protective coatings to prevent damage in harsh environments.

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Sanin, V. V., M. I. Aheiev, P. A. Loginov, M. Ya Bychkova, E. S. Shukman, L. Yu Mezhevaia, V. N. Sanin та T. A. Lobova. "Structural characteristics and properties of heat-resistant nickel β-alloys produced via the centrifugal SHS-casting method". Izvestiya. Non-Ferrous Metallurgy, № 1 (28 березня 2024): 24–41. http://dx.doi.org/10.17073/0021-3438-2024-1-24-41.

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Employing centrifugal self-propagating high-temperature synthesis (SHS) metallurgy, complemented by advanced metallurgical processes such as vacuum induction melting (VIM) and vacuum arc remelting (VAR), yielded the alloy formulation denoted as base–2.5Mo–1.5Re–1.5Ta–0.2Ti. This study investigates the effects of various technological modes and additional metallurgical treatments on the alloy's impurity and non-metallic inclusion content, structural characteristics, mechanical behavior under compression, and its oxidation mechanisms and kinetics when exposed to temperatures of 1150 °C for 30 h. With increasing centrifugal acceleration, the proportion of non-metallic inclusions (number of points) drops from 5 to 1–2 points. The best combination mechanical properties, including σucs = 1640 ± 20 MPa, σys = 1518 ± 10 MPa, and residual deformation were observed in alloys processed under conditions of increased gravitational force (g = 50). Within a centrifugal force range of g = 20÷300, the composition of the synthesis products aligned with the theoretical expectations. The total content of impurities is 0.15 ± 0.02 %, with a decrease in gas impurities–oxygen and nitrogen levels reduced to 0.018 % and 0.0011 %, respectively. The structural analysis of the alloys revealed the presence of globular and streaked inclusions of a chromium-based solid solution embedded within the matrix. Inclusions with thickness of 2–8 μm are present in the intergranular space: (Cr)Ni,Mo,Co, (Cr)Mo,Re and (Cr)Re,Mo. The formation of the Ni(Al,Ti) phase at grain boundaries was identified, contributing to an enhancement in plastic resistance and overall strength of the alloy. Oxidation mechanisms varied across different processing modes, with the size of structural components significantly influencing oxidation kinetics. The weight gain observed in SHS samples was 70 ± 10 g/m2 with oxidation predominantly occurring along the NiAl interphase boundaries and penetrating into the depth of the sample. TEM facilitated the identification of phases enriched with Ti microadditions, reducing the levels of dissolved nitrogen and oxygen within the intermetallic phase to a combined weight percentage (ΣO,N) of 0.0223 wt.%.

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Geanta, Victor, Ionelia Voiculescu, Radu Stefanoiu, Adrian Jianu, Ioan Milosan, Elena Manuela Stanciu, Alexandru Pascu, and Ion Mihai Vasile. "Titanium Influence on the Microstructure of FeCrAl Alloys Used for 4R Generation Nuclear Power Plants." Revista de Chimie 70, no. 2 (March 15, 2019): 549–54. http://dx.doi.org/10.37358/rc.19.2.6953.

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4R generation nuclear power plants should work with metallic material of the highest quality, capable to resist in maximum safe conditions for 25-30 years. FeCrAl alloys are capable of such performance, because of the resistance to: oxidation at high temperatures, corrosion, erosion and penetrating radiations in liquid metal environments. In addition, such materials are capable of forming on their surface some oxide layers, textured and self-renewable, with high adhesion to metallic substrates. These properties can be improved by microalloying with metal elements such as Ti, Zr, Y, Hf in amounts of 1 to 3%. These chemical elements have high affinity to oxygen, being able to stabilize the structure of the superficial layer of oxide (alumina) and to increase adhesion to the metallic substrate. The FeCrAl alloys microalloyed with titanium were obtained in a VAR (Vacuum Arc Remelting) equipment in argon atmosphere (99.99% purity). There were obtained three batches microalloyed with 0.5%, 1% and 1.5% titanium, preserving the same Fe-14Cr-5Al metal matrix. In order to determine the chemical composition of the oxide layer and of the sample bulk, the EDAX analysis was performed. Microstructural features were revealed using SEM analysis. The results showed the capacity of the FeCrAl alloy to form oxide layers, with different textures and rich in elements such as Al and Ti. The compositional analysis performed on FeCrAl samples microalloyed with 0.5, 1.0 and 1.5% Ti in the central zone shows a relatively similar composition compared to the technological calculations made, reflecting the homogeneity of the alloy. The microhardness measurements performed on the cross sections of the metallic samples attest values in the range 163-183 HV0.2, falling within the normal range for these materials. These values are influenced by the presence of the alloying elements in the metallic matrix and by the homogeneous arrangement of constituents.

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Craciun, Doina, Edwin A. Laszlo, Julia C. Mirza-Rosca, Gabriela Dorcioman, Victor Geanta, Ionelia Voiculescu, Gabriel Craciun, Liviu Badea, and Valentin Craciun. "Structural Parameters and Behavior in Simulated Body Fluid of High Entropy Alloy Thin Films." Materials 17, no. 5 (March 1, 2024): 1162. http://dx.doi.org/10.3390/ma17051162.

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The structure, composition and corrosion properties of thin films synthesized using the Pulsed Laser Deposition (PLD) technique starting from a three high entropy alloy (HEA) AlCoCrFeNix produced by vacuum arc remelting (VAR) method were investigated. The depositions were performed at room temperature on Si and mirror-like polished Ti substrates either under residual vacuum (low 10−7 mbar, films denoted HEA2, HEA6, and HEA10, which were grown from targets with Ni concentration molar ratio, x, equal to 0.4, 1.2, and 2.0, respectively) or under N2 (10−4 mbar, films denoted HEN2, HEN6, and HEN10 for the same Ni concentration molar ratios). The deposited films’ structures, investigated using Grazing Incidence X-ray Diffraction, showed the presence of face-centered cubic and body-centered cubic phases, while their surface morphology, investigated using scanning electron microscopy, exhibited a smooth surface with micrometer size droplets. The mass density and thickness were obtained from simulations of acquired X-ray reflectivity curves. The films’ elemental composition, estimated using the energy dispersion X-ray spectroscopy, was quite close to that of the targets used. X-ray Photoelectron Spectroscopy investigation showed that films deposited under a N2 atmosphere contained several percentages of N atoms in metallic nitride compounds. The electrochemical behavior of films under simulated body fluid (SBF) conditions was investigated by Open Circuit Potential (OCP) and Electrochemical Impedance Spectroscopy measurements. The measured OCP values increased over time, implying that a passive layer was formed on the surface of the films. It was observed that all films started to passivate in SBF solution, with the HEN6 film exhibiting the highest increase. The highest repassivation potential was exhibited by the same film, implying that it had the highest stability range of all analyzed films. Impedance measurements indicated high corrosion resistance values for HEA2, HEA6, and HEN6 samples. Much lower resistances were found for HEN10 and HEN2. Overall, HEN6 films exhibited the best corrosion behavior among the investigated films. It was noticed that for 24 h of immersion in SBF solution, this film was also a physical barrier to the corrosion process, not only a chemical one.

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BURDEK, Marek, Jarosław MARCISZ, Jerzy STĘPIEŃ, Ewelina SKOWRON, Zbigniew HAJDAK, Bogumiła KOWALIK, and Józef KRÓL. "Selected Properties of Input Stock Material for the Production of Thin-Walled Cylindrical Products by Cold Flow Forming." Problems of Mechatronics Armament Aviation Safety Engineering 10, no. 4 (December 30, 2019): 9–22. http://dx.doi.org/10.5604/01.3001.0013.6482.

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This paper presents test results for the steel grade 15HGMV metallurgical purity, microstructure, method of production and effect on the mechanical performance of the input stock material for calibre 227 mm missile motor casings manufactured by cold flow forming. The reference product for the determination of preliminary design criteria of missile casings of the higher calibre were calibre 122 mm missiles manufactured in Poland. The final mechanical properties of the casings are a cumulative effect of quenching and tempering and strain hardening during cold flow forming. The research and industrial practice carried out so far have demonstrated that the production process of a Feniks missile (with a 1.5 mm thick casing wall) requires steel grades of extremely high purity. This steel grade is manufactured by VAD (Vacuum Arc Degassing) melting, followed by ESR (ElectroSlag Remelting) or, alternatively by melting and casting in vacuum oven. The content of hard and non-deformable non-metallic inclusions such as oxides is critical to the success of cold flow forming. The cal. 227 mm missile casings feature walls approximately 2.5 mm thick and produced by cold flow forming from a quenched and tempered intermediate product. New material specifications should be developed for this reason to enable correct cold flow forming and contribute to a significant improvement in the cost efficiency of manufacturing. The investigations covered herein were guided by an assumption that the thicker wall sections might make the material specifications applicable to lower-calibre missiles to restrictive and obsolete about cal. 227 missiles. After initial laboratory tests, this hypothesis will be verified in industrial experiments on the production of prototype missile casings from input stock materials varying in metallurgical purity.

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Djambazov, G., V. Bojarevics, and K. Pericleous. "Vacuum arc remelting time dependent modelling." Magnetohydrodynamics 45, no. 4 (2009): 579–86. http://dx.doi.org/10.22364/mhd.45.4.12.

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Davidson, P. A., X. He, and A. J. Lowe. "Flow transitions in vacuum arc remelting." Materials Science and Technology 16, no. 6 (June 2000): 699–711. http://dx.doi.org/10.1179/026708300101508306.

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Starostin, B. M., Yu V. Kofman, N. I. Vorob’ev, A. F. Shkapa, and A. P. Shchetinin. "Electroslag remelting in vacuum arc furnaces." Metallurgist 42, no. 3 (May 1998): 103. http://dx.doi.org/10.1007/bf02765144.

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Shiina, Kentaro, and Shinichi Sasayama. "Manganese evaporation during vacuum arc furnace remelting." DENKI-SEIKO[ELECTRIC FURNACE STEEL] 56, no. 1 (1985): 23–29. http://dx.doi.org/10.4262/denkiseiko.56.23.

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Gartling, D. K., and P. A. Sackinger. "Finite element simulation of vacuum arc remelting." International Journal for Numerical Methods in Fluids 24, no. 12 (June 1997): 1271–89. http://dx.doi.org/10.1002/(sici)1097-0363(199706)24:12<1271::aid-fld559>3.0.co;2-#.

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YAMANAKA, Akihiro, and Hiroyuki ICHIHASI. "Vacuum Arc Remelting of Titanium with Rectangular Mold." Tetsu-to-Hagane 74, no. 6 (1988): 1021–27. http://dx.doi.org/10.2355/tetsutohagane1955.74.6_1021.

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43

Filimonov, A. V. "Analytical determination of the vacuum arc remelting parameters." Russian Metallurgy (Metally) 2012, no. 6 (June 2012): 475–77. http://dx.doi.org/10.1134/s0036029512060079.

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Zagrebelnyy, Dmytro, and Matthew John M. Krane. "Segregation Development in Multiple Melt Vacuum Arc Remelting." Metallurgical and Materials Transactions B 40, no. 3 (August 7, 2008): 281–88. http://dx.doi.org/10.1007/s11663-008-9163-5.

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45

Jardy, A. "Mathematical modelling of the vacuum arc remelting process." Revue de Métallurgie 100, no. 6 (June 2003): 595–605. http://dx.doi.org/10.1051/metal:2003122.

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Chapelle, P., J. P. Bellot, A. Jardy, T. Czerwiec, X. Robbe, B. Champin, and D. Ablitzer. "AN EXPERIMENTAL STUDY OF THE ELECTRIC ARC DURING VACUUM ARC REMELTING." High Temperature Material Processes (An International Quarterly of High-Technology Plasma Processes) 4, no. 4 (2000): 14. http://dx.doi.org/10.1615/hightempmatproc.v4.i4.40.

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Woodside, C. Rigel, Paul E. King, and Chris Nordlund. "Arc Distribution During the Vacuum Arc Remelting of Ti-6Al-4V." Metallurgical and Materials Transactions B 44, no. 1 (December 7, 2012): 154–65. http://dx.doi.org/10.1007/s11663-012-9760-1.

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Jing, Zhenquan, Rui Liu, Naitao Geng, Ying Wang, and Yanhui Sun. "Simulation of Solidification Structure in the Vacuum Arc Remelting Process of Titanium Alloy TC4 Based on 3D CAFE Method." Processes 12, no. 4 (April 16, 2024): 802. http://dx.doi.org/10.3390/pr12040802.

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Vacuum arc remelting is the main production method of titanium alloy ingots at present. In order to obtain good quality ingots, it is of great significance to study the formation of the solidification structure of ingots via vacuum arc remelting. In order to select and optimize the nucleation parameters for the solidification microstructure simulation of an ingot, a 3D CAFE model for microstructure evolution during vacuum arc remelting was established, taking into account heat transfer, flow, and solute diffusion. The Gaussian distribution continuous nucleation model and extended KGT model were used to describe the grain nucleation and dendrite tip growth rates, respectively. The multi-point mass source and moving boundary method were used to simulate the ingot growth. The results show that there are three typical crystal regions in the solidification structure of vacuum arc remelting titanium alloy ingots, namely the surface fine crystal region, columnar crystal region, and central equiaxed crystal region. The proportion of the columnar crystal region in the solidification structure of an ingot increases gradually with the increase in the undercooling of the maximum bulk nucleation. With an increase in the maximum bulk nucleation density, the equiaxed grain zone gradually increases, and the grain size gradually decreases. The proportion of the columnar crystal region in the solidification structure of an ingot increases gradually with an increase in the undercooling of the maximum bulk nucleation. The maximum volume nucleation variance has no obvious effect on the change in the solidification structure. When the maximum volume nucleation undercooling is 5.5 K, the maximum volume nucleation standard deviation is 4 K, and the maximum volume nucleation density is 5 × 108. The solidification structure simulation results are in good agreement with the experimental results.

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Shved, F. I. "Vacuum arc remelting of steel and alloys: Technological aspects." Steel in Translation 38, no. 12 (December 2008): 1033–39. http://dx.doi.org/10.3103/s096709120812022x.

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Belyanchikov, L. N. "Stabilization of vacuum arc remelting of steels and alloys." Russian Metallurgy (Metally) 2012, no. 12 (December 2012): 1017–21. http://dx.doi.org/10.1134/s0036029512120038.

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