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Letteratura scientifica selezionata sul tema "Solidification shrinkage"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 1 febbraio 2022

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Articoli di riviste sul tema "Solidification shrinkage"

Zhu, Li Guang, Jian Chen, Ying Xu, Cai Jun Zhang e Shuo Ming Wang. "Simulation on Steel Solidification and its Shrinkage in Mould of FTSC Slab". Advanced Materials Research 472-475 (febbraio 2012): 2018–23. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.2018.

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The solidification shrinkage of liquid steel has an important impact on thermal deformation behavior of high-temperature thin shell. Solidification shrinkage of liquid steel is an important basis for structure and shap optimization of the mould. In this paper, a direct coupled model was built on heat transfer in solidification and stress-strain by using the ANSYS software. And solidification shrinkage of liquid steel with the interior temperature and stress distribution were studied in the process of steel solidification, and it provided a theoretical basis for the further optimization of shape of the thin slab FTSC mould. This study was based on analysis of temperature and stress, deriving calculation of solidification shrinkage of steel’s phase change on macro-state by calculating the variation discipline of the distance between nodes.

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Rashid, Abira. "Optimization of Shrinkage Porosity in Grinding Media Balls by Casting Design Modification and Simulation Technique". International Journal for Research in Applied Science and Engineering Technology 9, n. VIII (15 agosto 2021): 344–53. http://dx.doi.org/10.22214/ijraset.2021.37352.

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Shrinkage porosity or cavity are associated with the solidification of the metal either due to gas/air entrapment or when the shrinkage occurring during solidification is not entirely compensated by the riser. Shrinkage cavities occurring in the casting reduces its strength which leads to unfulfillment of the desired serviceability. In this paper, casting design has been modified using the DISA manual to achieve directional solidification which directly relates to improvement of casting quality. The running of metal from pouring basin into casting along with solidification has been analysed through PROCAST which is a casting simulation software based on Finite Element Method and CAFE (Cellular Automata Finite Element) Model. The feeding system of the casting has been modified in terms of shape and volume to minimize air aspiration effect and promote directional solidification. The model used is of grinding media balls casting of high chromium cast iron. The feeding pattern, feeding velocity and solidification with respect to pouring temperature, pouring rate, ambient temperature and film coefficient has been analysed. The final optimum range of all parameters with corresponding minimum shrinkage porosity in casting was obtained. Main aim was to minimize shrinkage porosity in the main casting, ignoring gating and feeding system. The actual minimization of shrinkage porosity comes out around 56 %.

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He, Bin Feng, e Zhu Qing Zhao. "Numerical Simulation of Chilled Cast Iron Camshaft in Sand Casting Process". Applied Mechanics and Materials 44-47 (dicembre 2010): 117–21. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.117.

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There are many kinds of casting defects such as insufficient pouring, cooling separation, crack, and shrinkage and soon on were formed in the mold filling and the solidification process, which affect the final casting performance. Based on the mathematical models of mold filling and solidification process, the numerical simulation of chilled cast iron camshaft in sand casting process has been done. The filling behaviors at each stage in the filling process were presented. The temperature distributions in the solidification process were obtained, and the positions of shrinkages were predicted. According to the simulation results, an improved technology is proposed, and the shrinkages were eliminated efficiently. The simulation results are in good agreement with practical.

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Boonmee, Sarum, e Letrit Chuencharoen. "The Study of Solidification Behavior in Cast Irons Using the Linear Displacement Method". Solid State Phenomena 263 (settembre 2017): 77–81. http://dx.doi.org/10.4028/www.scientific.net/ssp.263.77.

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This study aims to assess the solidification shrinkage and expansion during the solidification of cast irons. The solidification shrinkage and expansion in cast irons are due to the formation of austenite and graphite respectively. In this study, the linear displacement method was used to observe the solidification event combined with the cooling curve analysis. It was found that the cooling and displacement curves show good correlations in time of events during solidification. The displacement due to graphite expansion increased with the carbon equivalent. The linear expansion of 0.2 to 1.9 mm was observed for the carbon equivalents ranged from 3.7 to 4.5. On the other hand, the displacement due to the austenite shrinkage was found to decrease with increasing carbon equivalents.

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Xiao, Feng, Renhui Yang, Liang Fang e Chi Zhang. "Solidification shrinkage of Ni–Cr alloys". Materials Science and Engineering: B 132, n. 1-2 (luglio 2006): 193–96. http://dx.doi.org/10.1016/j.mseb.2006.02.019.

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Ghomy, M. Emamy, e J. Campbell. "Solidification shrinkage in metal matrix composites". Cast Metals 8, n. 2 (luglio 1995): 115–22. http://dx.doi.org/10.1080/09534962.1995.11819199.

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Wable, Girish S., Srinivas Chada, Bryan Neal e Raymond A. Fournelle. "Solidification shrinkage defects in electronic solders". JOM 57, n. 6 (giugno 2005): 38–42. http://dx.doi.org/10.1007/s11837-005-0134-x.

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Korojy, B., L. Ekbom e H. Fredriksson. "Microsegregation and Solidification Shrinkage of Copper-Lead Base Alloys". Advances in Materials Science and Engineering 2009 (2009): 1–9. http://dx.doi.org/10.1155/2009/627937.

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Microsegregation and solidification shrinkage were studied on copper-lead base alloys. A series of solidification experiments was performed, using differential thermal analysis (DTA) to evaluate the solidification process. The chemical compositions of the different phases were measured via energy dispersive X-ray spectroscopy (EDS) for the Cu-Sn-Pb and the Cu-Sn-Zn-Pb systems. The results were compared with the calculated data according to Scheil's equation. The volume change during solidification was measured for the Cu-Pb and the Cu-Sn-Pb systems using a dilatometer that was developed to investigate the melting and solidification processes. A shrinkage model was used to explain the volume change during solidification. The theoretical model agreed reasonably well with the experimental results. The deviation appears to depend on the formation of lattice defects during the solidification process and consequently on the condensation of those defects at the end of the solidification process. The formation of lattice defects was supported by quenching experiments, giving a larger fraction of solid than expected from the equilibrium calculation.

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Liu, Jin Xiang, Ri Dong Liao e Zheng Xi Zuo. "Numerical Study on Solidification Process and Shrinkage Porosity for Engine Block Casting". Applied Mechanics and Materials 37-38 (novembre 2010): 753–56. http://dx.doi.org/10.4028/www.scientific.net/amm.37-38.753.

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The latent heat releasing and the criterion for shrinkage porosity in solidification progress of casting are studied. A numerical analysis is presented for solidification progress of the cylinder head casting using finite element method. The temperature distributions of the casting in different solidification phases are solved, and the shrinkage porosity is predicted. Based on this, the solidification progress of casting is evaluated. The simulation results can offer a helpful reference for casting design of cylinder head casting.

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Xie, Shi Kun, Rong Xi Yi, Zhi Gao, Xiang Xia, Cha Gen Hu e Xiu Yan Guo. "Effect of Rare Earth Ce on Casting Properties of Al-4.5Cu Alloy". Advanced Materials Research 136 (ottobre 2010): 1–4. http://dx.doi.org/10.4028/www.scientific.net/amr.136.1.

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The effects of adding rare earth Cerium on Al-4.5Cu alloy microstructure, solidification range and volume changes in the solidification process are researched. Experiments show that rare earth Cerium will bring remarkable effects on the alloy microstructure, solidification and solidification shrinkage interval. When the quantity of rare earth Cerium is about 4 wt%, the solid-liquid two phase of Al-4.5Cu alloy will range from 640°C to 600°C. The grains of the alloy are refined, round. The volume shrinkage is only 68.6% of that without adding rare earth Cerium.

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Più fonti

Tesi sul tema "Solidification shrinkage"

Khalajzadeh, Vahid. "Modeling of shrinkage porosity defect formation during alloy solidification". Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6155.

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Among all casting defects, shrinkage porosities could significantly reduce the strength of metal parts. As several critical components in aerospace and automotive industries are manufactured through casting processes, ensuring these parts are free of defects and are structurally sound is an important issue. This study investigates the formation of shrinkage-related defects in alloy solidification. To have a better understanding about the defect formation mechanisms, three sets of experimental studies were performed. In the first experiment, a real-time video radiography technique is used for the observation of pore nucleation and growth in a wedge-shaped A356 aluminum casting. An image-processing technique is developed to quantify the amount of through-thickness porosity observed in the real-time radiographic video. Experimental results reveal that the formation of shrinkage porosity in castings has two stages: 1-surface sink formation and 2- internal porosity evolution. The transition from surface sink to internal porosity is defined by a critical coherency limit of . In the second and third experimental sets, two Manganese-Steel (Mn-Steel) castings with different geometries are selected. Several thermocouples are placed at different locations in the sand molds and castings to capture the cooling of different parts during solidification. At the end of solidification, castings are sectioned to observe the porosity distributions on the cut surfaces. To develop alloys’ thermo-physical properties, MAGMAsoft (a casting simulation software package) is used for the thermal simulations. To assure that the thermal simulations are accurate, the properties are adjusted to get a good agreement between simulated and measured temperatures by thermocouples. Based on the knowledge obtained from the experimental observations, a mathematical model is developed for the prediction of shrinkage porosity in castings. The model, called “advanced feeding model”, includes 3D multi-phase continuity, momentum and pore growth rate equations which inputs the material properties and transient temperature fields, and outputs the feeding velocity, liquid pressure and porosity distributions in castings. To solve the model equations, a computational code with a finite-volume approach is developed for the flow calculations. To validate the model, predicted results are compared with the experimental data. The comparison results show that the advanced feeding model can accurately predict the occurrence of shrinkage porosity defects in metal castings. Finally, the model is optimized by performing several parametric studies on the model variables.

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Chen, Yin-Heng. "Study of solidification, shrinkage and natural convection in casting processes /". The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487676847114631.

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Lagerstedt, Anders. "On the shrinkage of metals and its effect in solidification processing". Doctoral thesis, KTH, Materials Science and Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-75.

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The shrinkage during solidification of aluminium and iron based alloys has been studied experimentally and theoretically. The determined shrinkage behaviour has been used in theoretical evaluation of shrinkage related phenomena during solidification.

Air gap formation was experimentally studied in cylindrical moulds. Aluminium based alloys were cast in a cast iron mould while iron based alloys were cast in a water-cooled copper mould. Displacements and temperatures were measured throughout the solidification process. The modelling work shows that the effect of vacancy incorporation during the solidification has to be taken into account in order to accurately describe the shrinkage.

Crack formation was studied during continuous casting of steel. A model for prediction of crack locations has been developed and extended to consider non-equilibrium solidification. The model demonstrates that the shrinkage due to vacancy condensation is an important parameter to regard when predicting crack formation.

The centreline segregation was studied, where the contributions from thermal and solidification shrinkage were analysed theoretically and compared with experimental findings. In order to compare macrosegregation in continuous casting and ingot casting, ingots cast with the same steel grade was analysed. However, the macrosegregation due to A-segregation is driven by the density difference due to segregation. This is also analysed experimentally as well as theoretically.

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Svidró, Péter. "Study of solidification and volume change in lamellar cast iron with respect to defect formation mechanisms". Licentiate thesis, KTH, Tillämpad processmetallurgi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-136985.

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Lamellar cast iron is a very important technical alloy and the most used material in the casting production, and especially in the automotive industry which is the major consumer. Beside the many great properties, it is inclined to form casting defects of which some can be prevented, and some may be repaired subsequently. Shrinkage porosity is a randomly returning problem, which is difficult to understand and to avoid. This defect is a volumetric deficiency which appear as cavities inside the casting in connection to the casting surface. Another frequent defect is the metal expansion penetration. This defect is a material surplus squeezed to the casting surface containing sand inclusion from the mold material. Shrinkage porosity is usually mentioned together with metal expansion penetration as the formation mechanism of both defects have common roots. It is also generally agreed, that these type of defects are related to the volumetric changes occurring during solidification. Additionally, the formation of these defects are in connection with the coherency of the primary austenite dendrites. The purpose of this work was to develop knowledge on factors affecting a volume-change related casting defect formation in order to minimize the presence of these defects in engine component production. This was done by extending the existing solidification investigation methods with novel solutions. Introduction of expansion force measurement in the determination of dendrite coherency combined with multi axial volume change measurement refine the interpretation of the solidification. Comparison of registered axial and radial linear deformation in cylindrical samples indicated an anisotropic volume change. Different methods for dendrite coherency determination have been compared. It was shown that the coherency develops over an interval. Dependent on the added inoculant the coherency is reached at different levels of fractions of a solidified primary phase. It is also shown, that inoculation has an effect on the nucleation and growth of the primary phase. Quantitative image analysis has been performed on the primary phase in special designed samples designed to provoke shrinkage porosity and metal expansion penetration. It was found, that the inter-dendritic space varies within a casting. This was explained by the coarsening of the primary dendrites which originates from differences in the local time of solidification.

QC 20131210

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Tadesse, Abel. "On the Volume Changes during the Solidification of Cast Irons and Peritectic Steels". Doctoral thesis, KTH, Metallernas gjutning, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-202558.

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This thesis work deals with the volume changes during the solidification of cast irons and peritectic steels. The volume changes in casting metals are related to the expansion and/or contraction of the molten metal during solidification. Often, different types of shrinkage, namely macro- and micro-shrinkage, affect the casting quality. In addition to that, exposure of the metal casting to higher contraction or expansion during the solidification might also be related to internal strain development in samples, which eventually leads to surface crack propagation in some types of steel alloys during continuous casting. In consequence, a deep understanding of the mechanisms and control of the solidification will improve casting quality and production. All of the experiments during the entire work were carried out on laboratory scale samples. Displacement changes during solidification were measured with the help of a Linear Variable Displacement Transformer (LVDT). All of the LVDT experiments were performed on samples inside a sand mould. Simultaneously, the cooling curves of the respective samples during solidification were recorded with a thermocouple. By combining the displacement and cooling curves, the volume changes was evaluated and later used to explain the influence of inoculants, carbon and cooling rates on volume shrinkages of the casting. Hypoeutectic grey cast iron (GCI) and nodular cast iron (NCI) with hypo-, hyper- and eutectic carbon compositions were considered in the experiments from cast iron group. High nickel alloy steel (Sandvik Sanbar 64) was also used from peritectic steel type. These materials were melted inside an induction furnace and treated with different types of inoculants before and during pouring in order to modify the composition. Samples that were taken from the LVDT experiments were investigated using a number of different methods in order to support the observations from the displacement measurements: Differential Thermal Analysis (DTA), to evaluate the different phase present; Dilatometry, to see the effect of cooling rates on contraction for the various types of alloys; metallographic studies with optical microscopy; Backscattered electrons (BSE) analysis on SEM S-3700N, to investigate the different types of oxide and sulphide nuclei; and bulk density measurements by applying Archimedes' principle. Furthermore, the experimental volume expansion during solidification was compared with the theoretically calculated values for GCI and NCI. It was found that the casting shows hardly any shrinkage during early solidification in GCI, but in the eutectic region the casting expands until the end of solidification. The measured and the calculated volume changes are close to one another, but the former shows more expansion. The addition of MBZCAS (Si, Ca, Zr, Ba, Mn and Al) promotes more flake graphite, and ASSC (Si, Ca, Sr and Al) does not increase the number of eutectic cells by much. In addition to that, it lowers the primary austenite fraction, promotes more eutectic growth and decreases undercooled graphite and secondary dendritic arm spacing (SDAS). As a result, the volume expansion changes in the eutectic region. The expansion during the eutectic growth increase with an increase in the inoculant weight percentage. At the same time, the eutectic cells become smaller and increase in number. The effect of the inoculant and the superheat temperature shows a variation in the degree of expansion/contraction and the cooling rates for the experiments. Effective inoculation tends to homogenize the eutectic structure, reducing the undercooled and interdendritic graphite throughout the structure. In NCI experiments, it was found that the samples showed no expansion in the transversal direction due to higher micro-shrinkages in the centre, whereas in the longitudinal direction the samples shows expansion until solidification was complete. The theoretical and measured volume changes agreed with each other. The austenite fraction and number of micro-shrinkage pores decreased with increase in carbon content. The nodule count and distribution changes with carbon content. The thermal contraction of NCI is not influenced by the variation in carbon content at lower cooling rates. The structural analysis and solidification simulation results for NCI show that the nodule size and count distribution along the cross-sections at various locations are different due to the variation in cooling rates and carbon concentration. Finer nodule graphite appears in the thinner sections and close to the mold walls. A coarser structure is distributed mostly in the last solidified location. The simulation result indicates that finer nodules are associated with higher cooling rate and a lower degree of microsegregation, whereas the coarser nodules are related to lower cooling rate and a higher degree of microsegregation. As a result, this structural variation influences the micro-shrinkage in different parts. The displacement change measurements show that the peritectic steel expands and/or contracts during the solidification. The primary austenite precipitation during the solidification in the metastable region is accompanied by gradual expansion on the casting sides. Primary δ-ferrite precipitation under stable phase diagram is complemented by a severe contraction during solidification. The microstructural analysis reveals that the only difference between the samples is grain refinement with Ti addition. Moreover, the severe contraction in solidification region might be the source for the crack formation due to strain development, and further theoretical analysis is required in the future to verify this observation.

QC 20170228

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O'Brien, Evan Daniel. "Welding with Low Alloy Steel Filler Metal of X65 Pipes Internally Clad with Alloy 625: Application in Pre-Salt Oil Extraction". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469018389.

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Drbušková, Magdaléna. "Numerická analýza smršťování vybraných silikátových kompozitů". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226798.

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The thesis is divided into two main parts. In the first theoretical part is described the problems of shrinking including a comparison of Czech standard and Model Code 2010, Vol. 1. The second practical part of the master`s thesis is focused on the numerical analysis shrinkage primarily on the initial stage of this process. The experimentally obtained data are set approximations of the relative deformation using ShrCeC. Subsequently the numerical simulation of shrinkage of selected silicate specimens using a computer applications SpatiDist and FyDiK 2D. The real test specimens are modelled as two-component composite consisting of cement paste and aggregates. The result is a parametric study takes into account the influence of type and size of grain aggregate.

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Šupálek, Milan. "Přesné lití turbínových kol turbodmychadel ze slitin TiAl". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228729.

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This diploma thesis focuses on the causes of surface shrinkages at tur-bochargers wheels castings made from TiAl alloy. On the basis of simulation of solidification and cooling, the defect is being repaired by the simulation software Procast.

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Bhattacharya, Anirban. "Effect of Convection and Shrinkage on Solidification and Microstructure Formation". Thesis, 2014. http://etd.iisc.ernet.in/handle/2005/2798.

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Understanding the fundamental mechanisms of solidification and the relative significance of different parameters governing these mechanisms is of vital importance for controlling the evolution of microstructure during solidification, and consequently, for improving the efficacy of a casting process. Towards achieving this goal, the present work attempts to study the effect of convection and shrinkage on solidification and microstructure formation primarily through the development of computational models which are complemented with experimental investigations and analytical solutions. Convection strongly influences the solutal and thermal distribution adjacent to the solidification interface and affects the growth rate and morphology of dendrites. To investigate this, a numerical model based on the enthalpy method is developed for binary alloy dendrite growth in presence of convection. The model results are validated with corresponding predictions using level-set method and micro-solvability theory. Subsequently, the model is applied for studying the effect of convection on the growth morphology of single dendrites. Results show that the presence of flow significantly affects the thermo-solutal distribution and consequently the growth rate and morphology of dendrites. Parametric studies performed using the model predict that thermal and solutal Peclet number and melt undercooling strongly influence the tip velocity of dendrites. Additionally, an analytical model is developed to quantify the effect of convection on dendrite tip velocity through the definition of an equivalent undercooling. An expression for this equivalent undercooling is derived in terms of the flow Nusselt and Sherwood numbers and the analytical equivalent undercooling values are compared with corresponding predictions obtained using the numerical model. Subsequently, the interaction of multiple dendrites growing in close proximity is studied. It is observed that the presence of neighbouring dendrites strongly influences the thermo-solutal distribution in the domain leading to significant changes in growth pattern. The effect of seed density on the growth morphology is investigated and it is observed that a higher initial seeding density leads to more spherical dendritic structure. Comparison with results from chilled casting of Al-6.5% Cu alloy with and without grain refiners show qualitative similarity in both the cases. The next part of the thesis presents a eutectic solidification model developed using the general enthalpy-based framework for dendritic solidification. New parameters and rules are defined and suitable modifications are made to incorporate the physics of eutectic solidification and account for the additional complexities arising due to the presence of multiple solid phases. The model simulates the presence of buoyancy driven convection and its interaction with the solidification process. i The model predictions are found to be in good agreement with the Jackson-Hunt theory. At first, the model is applied to simulate regular eutectic growth in a purely diffusive environment and it is observed that the model predicts the variation in interface profile with change in lamella width similar to those observed in experimental studies on eutectic solidification. Subsequently, a few case studies are performed to demonstrate the ability of the model in handling complex scenarios of eutectic growth such as width selection, lamella division and presence of solutal buoyancy. It is observed that solutal buoyancy gives rise to flow cells ahead of the eutectic interface facilitating the transfer of solute between the two phases. Apart from forced and natural convection, another important factor affecting solidification is the presence of shrinkage. Currently, solidification shrinkage is mostly modelled using empirical relations and criteria functions. In the present work, a phenomenological model for shrinkage driven convection is developed by incorporating the mechanism of solidification shrinkage in an existing framework of enthalpy based macro-scale solidification model. The effect of shrinkage flow on the free surface deformation is accounted for by using the volume-of-fluid method. The results predicted by the model are found to be in excellent agreement with analytical solutions for one-dimensional solidification with unequal phase densities. A set of controlled experiments are designed and executed for validating the numerical model. The experiments involve in-situ X-ray imaging of casting of pure aluminium in a rectangular cavity. The numerical predictions for solidification rate, free surface movement and temperature profiles are compared with corresponding experimental results obtained from the in-situ X-ray images and thermocouple data. Subsequent case studies, performed using the model, show significant influence of applied heat flux and mould geometry on the formation of shrinkage cavities. The shrinkage flow model provides the foundation for development of a generalized model to accurately predict the formation and morphology of internal porosity. The validated macro-scale shrinkage model is extended to the microscopic scale to study the influence of shrinkage flow on the growth rate of dendrites. Results demonstrate that shrinkage driven convection towards the dendrite strongly influences the solutal and thermal distribution adjacent to the solidification interface and consequently decreases the growth rate of the dendrite. Additionally, an analytical model is developed to quantify the effect of shrinkage driven convection through the definition of an equivalent undercooling for shrinkage flow. The present models provide significant physical insight into various mechanisms governing the process of solidification. Moreover, due to their similar framework, the individual models have the potential to be an effective foundation for the development of a generalized multi-scale solidification model incorporating the presence of important phenomena such as shrinkage and convection.

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Libri sul tema "Solidification shrinkage"

Society, American Foundrymen's, a cura di. Numerical simulation of mold filling, solidification, and feeding of T-plate shrinkage test castings used in ductile iron plant trials. [Des Plaines, Ill: American Foundrymen's Society, 1992.

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Capitoli di libri sul tema "Solidification shrinkage"

Mo, Asbjørn, Torgeir Rusten e Håvard J. Thevik. "Computation of Macrosegregation due to Solidification Shrinkage". In Numerical Methods and Software Tools in Industrial Mathematics, 177–94. Boston, MA: Birkhäuser Boston, 1997. http://dx.doi.org/10.1007/978-1-4612-1984-2_8.

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Petersen, Jon S. "Crystallization Shrinkage in the Region of Partial Solidification: Implications for Silicate Melts". In Structure and Dynamics of Partially Solidified Systems, 417–35. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3587-7_20.

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Saad, Ali, Charles-André Gandin, Michel Bellet, Thomas Volkman e Dieter Herlach. "Simulation of shrinkage-induced macrosegregation in a multicomponent alloy during reduced-gravity solidification". In TMS 2016: 145thAnnual Meeting & Exhibition: Supplemental Proceedings, 35–42. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119274896.ch5.

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Hennings, A., E. Schaberger-Zimmermann e A. Bührig-Polaczek. "Solidification Morphology and Shrinkage Behavior of Mg-Alloys in Chill- and Sand Casting". In Magnesium, 1020–25. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527603565.ch158.

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Eskine, Dmitri, e Laurens Katgerman. "Experimental Study of Linear Shrinkage during Solidification of Binary and Commercial Aluminum Alloys". In Continuous Casting, 276–81. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527607331.ch41.

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Saud, Ali, Charles-André Gandin, Michel Bellet, Thomas Volkmann e Dieter Herlach. "Simulation of shrinkage-induced macrosegregation in a multicomponent alloy during reduced-gravity solidification". In TMS 2016 145th Annual Meeting & Exhibition, 35–42. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-48254-5_5.

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Mortensen, Dag, Øyvind Jensen, Gerd-Ulrich Grün e Andreas Buchholz. "Macrosegregation Modelling of Large Sheet Ingots Including Grain Motion, Solidification Shrinkage and Mushy Zone Deformation". In Light Metals 2019, 983–90. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05864-7_120.

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Wei, Yimeng, Areti Markopoulou, Yuanshuang Zhu, Eduardo Chamorro Martin e Nikol Kirova. "Additive Manufacture of Cellulose Based Bio-Material on Architectural Scale". In Proceedings of the 2021 DigitalFUTURES, 286–304. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-5983-6_27.

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AbstractThere are severe environmental and ecological issues once we evaluate the architecture industry with LCA (Life Cycle Assessment), such as emission of CO2 caused by necessary high temperature for producing cement and significant amounts of Construction Demolition Waste (CDW) in deteriorated and obsolete buildings. One of the ways to solve these problems is Bio-Material. CELLULOSE and CHITON is the 1st and 2nd abundant substance in nature (Duro-Royo, J.: Aguahoja_Programmable Water-based Biocomposites for Digital Design and Fabrication across Scales. MIT, pp. 1–3 (2019)), which means significantly potential for architectural dimension production. Meanwhile, renewability and biodegradability make it more conducive to the current problem of construction pollution. The purpose of this study is to explore Cellulose Based Biomaterial and bring it into architectural scale additive manufacture that engages with performance in the material development, with respect to time of solidification and control of shrinkage, as well as offering mechanical strength. At present, the experiments have proved the possibility of developing a cellulose-chitosan- based composite into 3D-Printing Construction Material (Sanandiya, N.D., Vijay, Y., Dimopoulou, M., Dritsas, S., Fernandez, J.G.: Large-scale additive manufacturing with bioinspired cellulosic materials. Sci. Rep. 8(1), 1–5 (2018)). Moreover, The research shows that the characteristics (Such as waterproof, bending, compression, tensile, transparency) of the composite can be enhanced by different additives (such as xanthan gum, paper fiber, flour), which means it can be customized into various architectural components based on Performance Directional Optimization. This solution has a positive effect on environmental impact reduction and is of great significance in putting the architectural construction industry into a more environment-friendly and smart state.

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Campbell, John. "Solidification shrinkage". In Castings, 205–31. Elsevier, 2003. http://dx.doi.org/10.1016/b978-075064790-8/50024-3.

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Mahomed, Nawaz. "Shrinkage Porosity in Steel Sand Castings: Formation, Classification and Inspection". In Casting Processes and Modelling of Metallic Materials. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94392.

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In this Chapter, shrinkage porosity defects in steel castings are analysed, particularly for low carbon, high alloyed steels, which have applications in critical engineering components. It begins with the mechanisms for porosity formation within the solidification contraction phase of the casting cycle, highlighting the importance of feeder design. This is followed by characterisation of the solidification phase of steel alloys, including the evolution of phases, which is important in distinguishing between microstructure and porosity in microscopy analysis. A more detailed discussion of interdendritic feeding and mechanisms for shrinkage micro-porosity is then provided. This leads to the well-established interdendritic flow model and commonly-used thermal criteria for shrinkage porosity prediction. The discussions are then consolidated through the classification of shrinkage porosity in terms of formation mechanisms and morphology, and its causes relating to composition, design and process conditions. Finally, engineering standards for classification and inspection of porosity types and severity levels in steel castings are discussed. Throughout, basic design and process improvement approaches for improving melt feeding during solidification contraction is given, with emphasis on providing practical solutions for prediction and evaluation of shrinkage porosity defects in castings.

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Atti di convegni sul tema "Solidification shrinkage"

Wang, Hongda, Mohamed S. Hamed e S. Shankar. "EFFECT OF SHRINKAGE ON Al-Si ALLOY SOLIDIFICATION". In Proceedings of CHT-08 ICHMT International Symposium on Advances in Computational Heat Transfer. Connecticut: Begellhouse, 2008. http://dx.doi.org/10.1615/ichmt.2008.cht.2220.

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Alavi, Sina, e Mohammad Passandideh-Fard. "Numerical Simulation of Droplet Impact and Solidification Including Thermal Shrinkage in a Thermal Spray Process". In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-22583.

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In this paper, we performed a numerical study on the effects of thermal shrinkage on deposition of molten tin and nickel droplets on a steel substrate in thermal spray processes using Volume-of-Fluid (VOF) method. Thermal shrinkage is a phenomenon caused by variation of density during solidification and cooling of molten metals. In our model, the Navier-Stokes equations along with energy equation including phase change are solved using a 2-D axisymmetric mesh. We used the VOF method to track the free surface of droplet. For solidification, we used an enthalpy-porosity formulation. The simulations performed in this study are accomplished using a commercial code (Fluent). Results of these scenarios are presented: the normal impacts of 2.7mm tin droplets at 1m/s and 2m/s, initially at 240°C, onto a 27°C steel substrate. When the droplet impacts the substrate with a velocity of 1m/s, the final splat has a single cavity inside due to shrinkage. In other cases with the scales of a typical thermal spray process, the results of normal impact of nickel droplets with a velocity of 73m/s, initial temperature 1600°C and diameter 60μm to steel substrate with different temperatures are presented. In these cases shrinkage decreases the droplet splashing on the substrate.

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Dohnalová, L., e P. Havlásek. "SIZE EFFECT ON THE ULTIMATE DRYING SHRINKAGE OF CONCRETE – MODELING WITH MICROPRESTRESS-SOLIDIFICATION THEORY". In Engineering Mechanics 2020. Institute of Thermomechanics of the Czech Academy of Sciences, Prague, 2020. http://dx.doi.org/10.21495/5896-3-122.

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Sedeh, Mahmoud Moeini, e J. M. Khodadadi. "Effect of Voids on Solidification of Phase Change Materials Infiltrated in Graphite Foams". In ASME 2012 Heat Transfer Summer Conference collocated with the ASME 2012 Fluids Engineering Division Summer Meeting and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ht2012-58405.

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As a fundamental process during production of composite thermal energy storage systems, infiltration of phase change materials (PCM) leads to formation of voids (air pockets) inside the pores of graphite foams. The presence of voids inside graphite cells (i.e. the presence of air pockets next to the conductive walls of the porous structure) markedly affects the thermal and phase change behavior of the composite. Therefore, it is vitally important to investigate the effect of voids on phase change behavior of latent heat energy storage composites. In complementing recent work devoted to modeling of the infiltration of PCM into graphite foams, a numerical approach was employed to study the solidification of PCM infiltrated into a graphite pore in the presence of a void. For this purpose, a two-dimensional model of the porous structure was developed based on the typical geometrical features of the pores. Grid independence study was performed on different unstructured grid systems. Since more than one fluid phase is present in this problem (PCM being the liquid phase and air pocket or void as the gas phase), the volume-of-fluid (VOF) method was utilized for investigation of solidification problem and tracking the interface. Considering various forces operating at the scale of the pore (i.e. 500 microns in diameter), this problem is under the influence of surface tension, gravity, and pressure gradient. The simulation was transient and continued until the entire liquid PCM inside the pore freezes. The volume of final void space will represent a combination of infiltration and shrinkage voids. Results of the simulation indicate the presence of 9.8% void (from the infiltration process) that can greatly alter the solidification rate of the PCM inside the pore. It is concluded that formation of shrinkage void during solidification can be predicted using this multi-phase model. For verification purposes, the volume of the predicted infiltration void was compared to reported experimental measurements and the volume of shrinkage void was compared to theoretical volume change. Good agreements were found in both cases.

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Yomchinda, Thanan. "Modelling of solidification with shrinkage in vertical shell using particle method with spring-damp interaction". In 2017 Third Asian Conference on Defence Technology (ACDT). IEEE, 2017. http://dx.doi.org/10.1109/acdt.2017.7886175.

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Abdellatef, M., M. Alnaggar, G. Boumakis, G. Cusatis, G. Di-Luzio e R. Wendner. "Lattice Discrete Particle Modeling for Coupled Concrete Creep and Shrinkage Using the Solidification Microprestress Theory". In 10th International Conference on Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures. Reston, VA: American Society of Civil Engineers, 2015. http://dx.doi.org/10.1061/9780784479346.022.

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Rakita, Milan, e Qingyou Han. "Simulation of Solidification Defects for Prediction of Dross Formation in Aluminum 5182 Remelt Secondary Ingot". In ASME 2009 International Manufacturing Science and Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/msec2009-84160.

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In aluminum recycling about 4% on average is lost on oxidation and dross. However, large percent of remelt secondary ingots (RSI) produce much more dross after remelting. It is rather surprising that no dross can be detected in the RSI, but after remelting some parts of apparently ‘healthy’ aluminum can give up to 80% of dross. This raises question how dross gets formed. Recent research proposes that the formation of dross after remelting of the RSI is closely related to the solidification process in the ingot, specifically the formation of shrinkage porosity, hydrogen porosity, and hot tearing. Under these circumstances, dross comes from oxidized surfaces of those defects. In this paper, simulations of the RSI cooling down show susceptibility of ingots towards shrinkage porosity and hot tearing, which are in accordance with experimental findings. Simulations also show that dross is more likely to form with increased temperature of the mold and increased thickness of the ingot. The only efficient solution for the problem of dross formation, however, seems to be a change in geometry of the mold.

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Lauer, Mark A., David R. Poirier, Robert G. Erdmann, Luke Johnson e Surendra N. Tewari. "Simulations of the Effects of Mold Properties on Directional Solidification". In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-66830.

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The mold geometry and its thermal properties greatly influence the solidification process. Finite element simulations of directional solidification in various molds are presented. These simulations were performed using volume averaged properties in the mushy zone in order to model the convection, transport of solute and energy, and phase change occurring during solidification. These simulations show the interactions of the mold and alloy with the resultant solidification phenomena, including steepling. Mold geometries can cause macrosegregation because of shrinkage flows, by interrupting the development of the mushy zone, and by causing or influencing thermosolutal convection. Mold materials with different thermal properties result in different macrosegregation patterns even for the same geometries. Changes in cross section and the thermal properties of the mold also affect the gradients and solidification rates obtained in the alloy, as opposed to those measured on the mold wall. Simulations are compared qualitatively to a verification experiment of directionally solidifying a hypoeutectic Al-7wt%Si alloy in a mold with changing cross sections.

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Moeini Sedeh, Mahmoud, e J. M. Khodadadi. "Effect of Marangoni Convection on Solidification of Phase Change Materials Infiltrated in Porous Media in Presence of Voids". In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17316.

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Void formation is encountered in the form of air pockets during preparation of composite thermal energy storage systems, consisting of phase change materials (PCM) infiltrated into a high-conductivity porous structure. The presence of voids within the pores of a porous structure degrades the thermal and phase change behavior of such composites. Recent work devoted to multiphase modeling of the infiltration of PCM in liquid state into porous media and formation of voids showed that among the various contributing driving forces (i.e. gravity, pressure gradient and interfacial forces), the interfacial forces (resulting from surface tension and contact angle) play a significant role at the pore level. Additionally, modeling the solidification and melting of PCM within the pores in presence of a void revealed that there is a temperature gradient along the interface between the PCM and void. Considering the surface tension as the major driving force at the pore level, this temperature gradient is large enough to give rise to a gradient in surface tension that then triggers the Marangoni convection at the interface. Thus, as a convection mechanism, it affects the phase change process as well as the interface shape. Therefore, in this paper, the effects of the Marangoni convection on PCM solidification time and shape of the interface was investigated at the pore level. A numerical approach was employed for solidification of a PCM based on the combination of the Volume-of-fluid (VOF) and enthalpy-porosity methods, including the variation of the surface tension with temperature, i.e. Marangoni effects. A two-dimensional model of a pore was developed based on the average geometric features of the pores in a porous structure with interconnecting pores. Following the grid independence study, the transient simulation of solidification was performed, whereas the PCM within the pore and the air within the void were treated as incompressible liquid and compressible gas, respectively. The liquid density change during the solidification was included to explicate the formation of shrinkage void and its distribution within the pores. The PCM solidification time and shape of the final interface between the PCM and air pocket (representing the amount and distribution of the shrinkage void evolving during the solidification) were extracted and compared between the cases with and without Marangoni convection. For verification purposes, the volume of the predicted infiltration void is in agreement with experimental measurements and the volume of the shrinkage void shows a good agreement with theoretical volume change. The final shape of the interface was justified and turned out to be in agreement with the prevailing Marangoni convection pattern.

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Liu, Min-Jie, Zi-Qin Zhu, Li-Wu Fan e Zi-Tao Yu. "An Experimental Study of Inward Solidification of Nano-Enhanced Phase Change Materials (NePCM) Inside a Spherical Capsule". In ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ht2016-7317.

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Nano-enhanced phase change materials (PCM), referred to as NePCM, have been proposed by doping highly thermally-conductive nanofillers into matrix PCM to prepare composites that have enhanced thermal conductivity. The classical problem of inward solidification of PCM inside a spherical capsule, with applications to thermal energy storage, was revisited in the presence of nanofillers. In this work, the model NePCM samples were prepared with 1-tetradecanol (C14H30O) possessing a nominal melting point of 37 °C as the matrix PCM. Graphite nanoplatelets (GNPs) were synthesized and utilized as the nanofillers at loadings up to 1% by weight. The transient phase change and heat transfer during solidification were characterized by means of an indirect method that is based on the knowledge of transient volume shrinkage of the PCM. The experimental results showed that the total solidification time becomes shorter with increasing the loading of GNPs, in accordance to the increased effective thermal conductivity of the NePCM samples.

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