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Hosking, Timothy Donald, and mikewood@deakin edu au. "Casting yield improvement in graphitic iron castings." Deakin University. School of Engineering and Technology, 2001. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20051017.122220.
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A well designed runner and feeding system should produce castings with minimal defects and low pour weight. This thesis investigates how the filling regime and solidification of the mould influences defects in the castings produced from that mould. Design guidelines to reduce such defects are proposed and tested.
An existing shrinkage fault in a Grey Iron disc brake casting is simulated using a commercial finite-difference computer program. Three criteria are used to predict the defect and the effect of changes to the feeder geometry. Critical Fraction Solidification analysis is used to determine whether the feeder remains in liquid contact with the casting during solidification and this approach is shown to correctly predict the presence or absence of porosity* The feeder block is extended below the ingate of the casting to improve liquid contact between the casting and feeder without significantly increasing the feeder mass. Plant trials confirm the change to the feeder eliminates the porosity defect.
The runner system and mould venting for a thin walled Ductile Iron casting are investigated. Trials show that by setting the total mould vent area to be greater than the net ingate area of the castings, the cold-shut frequency is halved. A method for runner system design based on peak linear flow velocity in the runner during mould filling is proposed. A new pressurised runner system produces castings with significantly fewer defects and reduced pour weight when runner areas are designed to maintain peak velocity below 1 m/s. Peak velocity and magnesium levels are demonstrated to be critical factors in the elimination of cold-shut defects. A pressurised runner system is also shown to isolate inclusion defects from castings more effectively than an unpressurised system.
From this work, a technique is proposed which allows the yield of an existing runner and feeder system for iron castings to be improved with confidence in the results.
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Umaru, Darma Katsina. "Task and need analysis of metal work casting in Katsina State of Nigeria." Online version, 2009. http://www.uwstout.edu/lib/thesis/2009/2009darmak.pdf.
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Dewhirst, Brian A. "Castability Control in Metal Casting via Fluidity Measures: Application of Error Analysis to Variations in Fluidity Testing." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-121608-125755/.
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Thesis (Ph. D.)--Worcester Polytechnic Institute.Keywords: castability; metal casting; error analysis; casting fluidity; a356; solidification processing; fluidity. Includes bibliographical references (leaves 85-90).
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Deez, Brent Steven. "An investigation on the suitability of layer manufacturing methods for rapid tooling development in investment casting of light metal alloys." Thesis, Cape Peninsula University of Technology, 2010. http://hdl.handle.net/20.500.11838/2228.
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Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2010.The research presented in this report focuses on Investment Casting capabilities for light metal alloys in South Africa and forms part of the Advanced Manufacturing Technology Strategy's (AMTS): Light Weight Metals flagship programme. The research is centred on the suitability of rapid prototyping (RP)/Iayer manufacturing (LM) methods to produce patterns for the investment casting of aluminium (AI), magnesium (Mg) and titanium (Ti) alloys, together known as Rapid Investment Casting. Three core RP technologies are investigated namely: Three Dimensional Printing - Drop-on-Bed from Z-corporation, Three Dimensional Printing - Drop-on- Drop from ThermoJet - 3D Systems and Selective Laser Sintering from EOS. Various RP/LM processes are discussed in detail and highlight the technologies selected in this study. A standard benchmark part, adapted from the European project framework FP6, designed and utilised in similar studies is used as the basis for the research. The Investment Casting process is discussed fully and compared to the Rapid Investment Casting, listing both the advantages and disadvantages of the above mentioned methods. In addition a special study has been conducted on investment casting of large components using layer manufactured patterns. This study not only helped to establish and validate the shrinkage value calculated for the aluminium castings but also showed substantial capability lacks in SA foundries to handle this type of components, which are by definition most often of high added value.
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Matys, Paul. "Fluid flow and heat transfer in continuous casting processes." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28504.
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A three-dimensional finite difference code was developed to simulate fluid flow and heat transfer phenomena in continuous casting processes.
The mathematical model describes steady state transport phenomena in a three dimensional solution domain that involves: turbulent fluid flow, natural and forced convection, conduction, release of latent heat at the solidus surface, and tracing of unknown location of liquid/solid interface.
The governing differential equations are discretized using a finite volume method and a hybrid central, upwind differencing scheme. A fully three-dimensional ADI-like iterative procedure is used to solve the discretized algebraic equations for each dependent variable. The whole system of interlinked equations is solved by the SIMPLE algorithm.
The developed computer code was used for parametric studies of continuous casting of aluminum. The results were compared against available experimental data. This numerical simulation enhances understanding of the fluid flow and heat transfer phenomena in continuous casting processes and can be used as a tool to optimize technologies for continuous casting of metals.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
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Bernard, William J. "The continuous rheoconversion process Scale-up and optimization." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-082305-102150/.
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Hugo, Philip. "Suitability of layer manufacturing technologies for rapid tooling development in investment casting." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/847.
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Ahmad, Nadiah. "Riser Feeding Evaluation Method for Metal Castings Using Numerical Analysis." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1447845668.
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Wang, Enhai. "Metal-mold reactions in CMSX-4 single crystal superalloy castings." abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1464425.
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Charmeux, Jean-Francois. "Capabilities of the Investment Casting process for producing meso/micro metal castings using Rapid Prototyping manufacturing routes." Thesis, Cardiff University, 2007. http://orca.cf.ac.uk/54701/.
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This thesis examines the capabilities of different Rapid Prototyping (RP) manufacturing processes for producing sound metallic parts incorporating features in the micrometre range using the Investment Casting (IC) process. RP has been growing in the past twenty years and is nowadays widely employed in the area of precision investment casting since the technology offers the possibility of manufacturing wax patterns which can be directly implemented into investment casting. Owing to the steady improvements of the technology, some of the recently developed RP building machines offer the possibility of manufacturing small parts incorporating micro-features. In this work, a detailed description of the accuracy and capabilities of the IC process regarding its potential for producing sound meso/micro components is given using two types of conventional RP machines. The results of this analysis are then compared through a benchmarking study with a recently developed RP process suitable for the direct manufacture of ceramic moulds. The different technological chains are compared regarding their overall accuracy, surface finish, the amount of structural defects present in the castings and their relative production costs and lead-time. Finally, the potential of the investment casting process for manufacturing sound micro-castings with high aspect ratio is approached from a structural point of view. Through a metallographic analysis study, the research investigates the size-scale effect of cast micro-components upon their microstructure and the subsequent changes in their mechanical properties.
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Findon, Matthew M. "Semi-solid slurry formation via liquid metal mixing." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0721103-161140/.
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Tjoa, Robertus Tjin Hok Carleton University Dissertation Engineering Mechanical. "Assessment of the accuracy of a computational casting model." Ottawa, 1992.
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Dewhirst, Brian A. "Optimization of the heat treatment of semi solid processed A356 aluminum alloy." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-111705-111503/.
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Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: microstructure; casting; Fluid Bed; Quality Index; Aluminum; A356; heat treatment; SSM; Semi Solid Metal Includes bibliographical references. (p.105-106)
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Hong, Fangjun. "Droplet spreading, substrate remelting and variable thermal contact resistance in microcasting /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?MECH%202005%20HONG.
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Xue, Xingjian. "IMPROVEMENTS ON HEAT FLUX AND HEAT CONDUCTANCE ESTIMATION WITH APPLICATIONS TO METAL CASTINGS." MSSTATE, 2003. http://sun.library.msstate.edu/ETD-db/theses/available/etd-08042003-091324/.
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Heat flux and heat conductance at the metal mold interface plays a key role in controlling the final metal casting strength. It is difficult to obtain these parameters through direct measurement because of the required placement of sensors, however they can be obtained through inverse heat conduction calculations. Existing inverse heat conduction methods are analyzed and classified into three categories, i.e., direct inverse methods, observer-based methods and optimization methods. The solution of the direct inverse methods is based on the linear relationship between heat flux and temperature (either in the time domain or in the frequency domain) and is calculated in batch mode. The observer-based method consists on the application of observer theory to the inverse heat conduction problem. The prominent characteristic in this category is online estimation, but the methods in this category show weak robustness. Transforming estimation problems into optimization problems forms the methods in the third category. The methods in third category show very good robustness property and can be easily extended to multidimensional and nonlinear problems. The unknown parameters in some inverse heat conduction methods can be obtained by a proposed calibration procedure. A two-index property evaluation (accuracy and robustness) is also proposed to evaluate inverse heat conduction methods and thus determine which method is suitable for a given situation. The thermocouple dynamics effect on inverse calculation is also analyzed. If the thermocouple dynamics is omitted in the inverse calculation, the time constant of thermocouple should be as small as possible. Finally, a simple model is provided simulating the temperature measurement using a thermocouple. FEA (Finite Element Analysis) is employed to simulate temperature measurement.
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Majidi, Seyyed Hojjat. "Modeling of air entrainment and oxide inclusion formation during pouring of metal castings." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6611.
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Oxide inclusions are among the most commonly reported defects in ferrous and non-ferrous castings. They affect the surface quality, machinability, and mechanical performance of a cast part. Air entrainment during mold filling is the main source of the oxygen that is consumed in inclusion formation. A quantitative understanding of the formation mechanisms or the prediction of final amounts and locations of oxide inclusions in metal castings is not available. Ductile iron experiments are conducted to study the formation of oxide inclusions during pouring. Oxide inclusions are measured by serial sectioning of the solidified castings. The effect of different gating systems, section thicknesses, and surface orientations on the inclusion formation and final distribution is studied. In addition, a computational model is developed for predicting the formation, motion and final location of oxide inclusions during pouring of metal castings, with the focus on the important mechanism of generation of oxide inclusions due to air entrainment during mold filling. The developed model calculates the local air entrainment rate as a function of the turbulent kinetic energy and the magnitude of the normal velocity gradient of the liquid metal at the liquid-air interface. The turbulent kinetic energy is estimated from the sum of the squares of the fluctuating velocity components relative to a spatially averaged mean velocity. The air entrainment model is implemented in a casting simulation software and validated by comparing its predictions to experimental air entrainment measurements for a circular water jet plunging into a quiescent pool. The liquid velocity, diameter and the turbulence intensity dependence is determined by a single entrainment coefficient. Oxide inclusions are then generated at the liquid-air interface, transported with the melt flow under the combined influences of drag and buoyancy, and captured by the solidifying casting surface. The developed model provides a powerful technique for predicting the oxide inclusion formation and final location.
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Lim, Chu-Sing. "The production and evaluation of fibre preform-infiltrated metal matrix composite castings produced by a developed pressure-assisted investment casting process." Thesis, Loughborough University, 1995. https://dspace.lboro.ac.uk/2134/28175.
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The squeeze casting process is well known for its ability to produce castings with good integrity due to the high direct pressure application on the liquid metal during solidification. This concept has been used to squeeze infiltrate fibre preforms with liquid metal for metal-matrix composite (MMC) production. Squeeze casting employs fast cycle times to produce high integrity castings. The squeeze casting process is, however, limited in terms of shape complexity and flexibility (e.g. thin sections). One-offs or small production runs become very expensive to produce because of the complex nature and high cost of the die steel tooling.
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Ajayi, Frederick Adegbola. "A transient multi-physics algorithm for solidification residual stress in metal components." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287951.
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Kolar, Venkat Deepak. "Application of reverse engineering and rapid prototyping to casting." Cleveland, Ohio : Cleveland State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=csu1210805699.
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Thesis (M.S.)--Cleveland State University, 2008.Abstract. Title from PDF t.p. (viewed on July 3, 2008). Includes bibliographical references (p.56-57). Available online via the OhioLINK ETD Center. Also available in print.
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Winardi, Leonard. "Procedures for predicting pressures inside cores." Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2009r/winardi..pdf.
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Thesis (Ph. D.)--University of Alabama at Birmingham, 2007.Title from PDF of title page (viewed October 13, 2009). Additional advisors: J. Barry Andrews, Gregg M. Janowski, Peter M. Walsh, Srinath Viswanathan, Harry E. Littleton. Includes bibliographical references (p. 207-209).
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Bernard, III William J. "The Continuous Rheoconversion Process: Scale-up and Optimization." Digital WPI, 2005. https://digitalcommons.wpi.edu/etd-theses/957.
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"Semi-solid metal (SSM) processing has emerged as a preferred manufacturing method due to the superior quality associated with semi-solid castings. In recent years, the driving force to reduce process cost has led to the development of a few rheocasting (also termed slurry-on-demand) processes. These include UBE’s New Rheocasting (NRC) process [1], Idra Prince’s Semi-Solid Rheocasting (SSR) process [2], and THT’s Sub-Liquidus Casting (SLC®) process [3]. A novel slurry-making SSM process developed at ACRC/MPI, termed the “Continuous Rheoconversion Process†(CRP), is a passive liquid mixing technique in which the nucleation and growth of the primary phase are controlled using a specially designed “reactorâ€. The reactor provides heat extraction, copious nucleation and forced convection during the initial stage of solidification, leading to the formation of thixotropic structures. In these studies, the critical issues/challenges to optimize the CRP for industrial applications have been addressed through validation experiments and pre-industrial trials."
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Chen, Qi. "The effect of transition metal additions on double oxide film defects in Al alloy castings." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7404/.
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This work investigated the effect of transition metal additions on the double oxide film defects in Al alloys. A bubble trapping experiment was initially conducted, which deliberately trapped an air bubble inside the aluminium melt for a period of time in three different Al alloys (Commercial purity aluminium, 2L99(Al-7Si-0.35Mg) and Al-5Mg alloy), as an analogy of the consumption of the entrapped atmosphere in double oxide film defects in castings. Several elements, namely, Mo, Ti, Zr, Hf, Sc were selected and added into the aluminium melt. The result suggested that the three different alloys behaved differently with regard to the consumption of the entrapped bubble and the different oxide/nitride layers formed. Only the addition of Sc and Mo altered the structure of the oxide surface and promoted the consumption of the air in the trapped bubble in the 2L99 aluminium alloy melt. Sand casting was subsequently conducted for 2L99 alloy with different element additions. Mo and W were found to improve the Weibull moduli of the UTS. Statistical analysis confirmed that such improvement was significant. For the castings with Mo addition, a nitride was found in some double oxide film defects, on the fracture surface of the tensile testbars. This was unusual, as bi-film defects in aluminium castings usually have a short solidification time and do not have enough time to consume the majority of their entrapped oxygen. The formation of the nitride on the surface of bi-film defects in +Mo castings, suggested that the majority of the oxygen was depleted and a reaction was going on between nitrogen and liquid aluminium. The formation of the permeable nitride surface layer on the bifilm defect might promote the consumption of the entrapped gas. This should lead to reductions in the bi-film size and an improvement in mechanical properties. For +W casting, W containing intermetallic compound might be nucleated on the sides of the bifilm and drag the bi-film to the bottom of the casting, resulting in a clean melt and improving mechanical properties. The effect of Si modifier addition on the bi-film defect (Na, Sr and Ba) in 2L99 sand castings was also investigated, which suggested the addition of modifiers resulted in a reduction in the mechanical properties of the 2L99 castings while the bi-film defect content in the casting was high but significantly improved the Weibull moduli of the UTS of 2L99 castings while the bi-film defect content was reduced. The results suggested that the modifier addition tended to aggravate the effect of bi-film defects on mechanical properties by increasing the defect size. Ti and Mn additions into 2L99 alloy were found to not significantly affect the mechanical properties of the casting. A porous oxide structure was found on only one of the fracture surfaces (out of ten) of Ti containing testbar examined, which hardly affect the mechanical properties of the casting. For the +Mn casting, the composition and structure of the oxide was not affected by the addition. The reduction of the mean value of the UTS for both element additions could be due to bi-film defects being introduced during master alloy preparation, master alloy addition and during degassing before casting.
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Beshay, Youssef Kamal. "The application of positron emission particle tracking to study non-metallic inclusions in metal castings." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1327/.
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To improve the efficiency of turbine aero engines, higher operating temperatures and weight savings are being investigated. Alloys such as RR1000 are being trialled as they perform better at higher temperatures than current nickel-based superalloys. To achieve weight savings, inertia welding is being trialled for turbine discs but current post weld heat treatments reduce fatigue life. In this investigation, a number of novel post weld heat treatments were trialled aimed at improving post weld microstructure and fatigue properties. Extensive microstructural characterisation and mechanical testing were used to assess the effect of these treatments on both parent and weld materials. Post weld heat treatment (PWHT) was found to have a great effect on the size and distribution of γ' and carbides, particularly when a PWHT temperature of 980ºC or above was used. The effect of this microstructural change on the hardness of the weld and parent material has also been characterised. Extensive total life fatigue testing was carried out at 650ºC. It was found that failure can occur in both the parent and weld material, although it is deduced that the yield stress of the weld needs to be surpassed to see weld failure (plasticity in the weld). Increasing dwell time at peak load reduced the life of these components. Two mechanisms for crack growth were observed with initiation either at the surface or at a large Hf rich particle subsurface. Oxidation was found to have a large effect on both initiation and growth of fatigue cracks. By introducing a sharp pre-fatigue crack into samples, static load testing was used to determine a threshold value of K (stress intensity factor) for growth and growth rates were plotted at different K values. It was seen in these tests that PWHT had a large effect on growth rates and threshold values of K.
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Uddin, Salah. "Semi-analytical and numerical modeling of microsegregation for solidifying metallic alloys." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112587.
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In this study, two semi-analytical models of microsegregation were developed to predict the concentration fields of solute in the liquid and solid regions for dendritic solidification of binary metallic alloys. Both models assume that the growing dendrites are cylindrical in shape. This assumption is more realistic compared to the common assumptions of plate-like dendrites that most of the earlier researchers employed in their microsegregation modeling study. The solute redistribution profile, in the developing solid layer, necessary to determine the back diffusion parameter was derived from Fick's second law for the model without coarsening. The application of this parameter in a wide range of conditions and the use of its basic form in the model with coarsening was verified. The concept of coordinate transformation and enhancement of back-diffusion Fourier number were used in deriving the model which took into account the coarsening of dendrites. The models are then extended to deal with rapid solidification, peritectic transformations and multi-component systems and the results were compared with relevant experimental data. A good agreement between the model predictions and experimental results was found.The second part of this study was focused on developing a fully numerical microsegregation model. The numerical model built upon a previously proposed phase change model which relied upon a coordinate transformation technique. The model was extended to deal with moving boundaries with solute diffusion. A suitable computational procedure was developed to solve the model equations which are strongly coupled to each other. To verify the accuracy of the present algorithm with regard to the capability of tracking the moving interfaces, analytical solution of the Stefan problem was used for verification purposes. A good agreement between the model predictions and the analytical solution was found. Evolution of concentration fields during solidification was calculated in the growing solid as well as in the shrinking liquid regions for rectangular, cylindrical and spherical dendrite geometries. The effects of various cooling conditions and relevant parametric values on microsegregation were analyzed and discussed.
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Warke, Virendra S. "Removal of Hydrogen and Solid Particles from Molten Aluminum Alloys in the Rotating Impeller Degasser: Mathematical Models and Computer Simulations." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0626103-111317.
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Nyembwe, Kasongo Didier. "Tool manufacturing by metal casting in sand moulds produced by additive manufacturing processes." Thesis, Bloemfontein : Central University of Technology, Free State, 2012. http://hdl.handle.net/11462/162.
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Thesis (D. Tech. ( Mechanical Engineering )) - Central University of technology, Free State, 2012In this study an alternative indirect Rapid Tooling process is proposed. It essentially consists of producing sand moulds by Additive Manufacturing (AM) processes followed by casting of tools in the moulds. Various features of this tool making method have been investigated. A process chain for the proposed tool manufacturing method was conceptually developed. This process chain referred to as Rapid Casting for Tooling (RCT) is made up of five steps including Computer Aided Design (CAD) modeling, casting simulation, AM of moulds, metal casting and finishing operations. A validation stage is also provided to determine the suitability of the tool geometry and material for RCT. The theoretical assessment of the RCT process chain indicated that it has potential benefits such as short manufacturing time, low manufacturing cost and good quality of tools in terms of surface finish and dimensional accuracy. Focusing on the step of AM of the sand moulds, the selection of available AM processes between the Laser Sintering (LS) using an EOSINT S 700 machine and Three Dimensional Printing using a Z-Corporation Spectrum 550 printer was addressed by means of the Analytic Hierarchy Process (AHP). The criteria considered at this stage were manufacturing time, manufacturing cost, surface finish and dimensional accuracy. LS was found to be the most suitable for RCT compared to Three Dimensional Printing. The overall preferences for these two alternatives were respectively calculated at 73% and 27%. LS was then used as the default AM process of sand moulds in the present research work. A practical implementation of RCT to the manufacturing of foundry tooling used a case study provided by a local foundry. It consisted of the production of a sand casting pattern in cast iron for a high pressure moulding machine. The investigation confirmed the feasibility of RCT for producing foundry tools. In addition it demonstrated the crucial role of casting simulation in the prevention of casting defects and the prediction of tool properties. The challenges of RCT were found to be exogenous mainly related to workmanship. An assessment of RCT manufacturing time and cost was conducted using the case study above mentioned as well as an additional one dealing with the manufacturing of an aluminium die for the production of lost wax patterns. Durations and prices of RCT steps were carefully recorded and aggregated. The results indicated that the AM of moulds was the rate determining and cost driving step of RCT if procurement of technology was considered to be a sunk cost. Overall RCT was found to be faster but more expensive than machining and investment casting. Modern surface analyses and scanning techniques were used to assess the quality of RCT tools in terms of surface finish and dimensional accuracy. The best surface finish obtained for the cast dies had Ra and Rz respectively equal to 3.23 μm and 11.38 μm. In terms of dimensional accuracy, 82% of cast die points coincided with die Computer Aided Design (CAD) data which is within the typical tolerances of sand cast products. The investigation also showed that mould coating contributed slightly to the improvement of the cast tool surface finish. Finally this study also found that the additive manufacturing of the sand mould was the chief factor responsible for the loss of dimensional accuracy. Because of the above, it was concluded that light machining will always be required to improve the surface finish and the dimensional accuracy of cast tools. Durability was the last characteristic of RCT tools to be assessed. This property was empirically inferred from the mechanical properties and metallographic analysis of castings. Merit of durability figures of 0.048 to 0.152 were obtained for the cast tools. It was found that tools obtained from Direct Croning (DC) moulds have merit of durability figures three times higher than the tools produced from Z-Cast moulds thus a better resistance to abrasion wear of the former tools compared to the latter.
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Moosbrugger, John C. "Numerical computation of metal/mold boundary heat flux in sand castings using a finite element enthalpy model." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/16365.
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Bainbridge, Ian Frank. "The influence of molten metal surface properties on the formation of surface defects on vertical direct chill cast aluminium alloy products /." [St. Lucia, Qld.], 2005. http://adt.library.uq.edu.au/public/adt-QU20060116.141809/index.html.
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Saha, Deepak. "Novel Processing Methods and Mechanisms to Control the Cast Microstructure in Al Based Alloys - 390 and Wrought Alloys." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-041405-150300/.
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Entwistle, Jeremy. "Metal casting the fire of art and industry /." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5179.
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Thesis (M.F.A.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains iii, 45 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 43).
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Papworth, Adam John. "Squeeze-casting of fibre reinforced metal matrix composites." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364201.
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Taylor, John A. "The lost wax casting technique." Virtual Press, 1993. http://liblink.bsu.edu/uhtbin/catkey/864921.
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The primary objective of this creative project was to fully explore and analyze the centuries old technique of lost wax casting.The secondary objective was to produce a body of work combining my creative inspirations from nature and my African culture.This body of work employed a variety of traditional metalsmithing techniques combining raised/constructed hollow ware, in a variety of metals, with cast metal forms.Department of Art
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Ogbogu, S. O. E. "Electromagnetic stirring in the continuous casting of molten metal." Thesis, University of Bradford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374933.
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Kayikci, Ramazan. "Metal-mould contact and heat transfer during casting solidification." Thesis, University of Manchester, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681341.
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Rothén, Niclas, and Jacob Aho. "Semi Solid Metal Casting : Study Of Slurry Preperation Parameters." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Maskinteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-36446.
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This thesis work is an experimental study of one type of Semi-Solid Metal casting (SSM) process which is called RheoMetalTM. This method is an efficient type of Rheocasting that creates a semi-solid slurry within 30 seconds that is used for a high pressure die casting machine. The purpose of using a slurry in a high pressure die casting machine is that the slurry has a higher viscosity due to its solid fraction. This makes the filling of the die cavity more laminar which reduces air entrapment in the casting. The difficulty with this type of casting is to control the process parameters to be able to insure a casting with desired properties. A few studies within RheoMetalTM has already been made but there is still a lack of knowledge of to what extent the process parameters affect the slurry. The goal in this work is to study how the different RheoMetalTM process parameters influence the primary α-Al solid fraction, shape and size. The process parameters that were studied in this work was the stirring rate, superheat and EEM amount. In this study, the so called growth layer has been removed to make more precise calculations of the primary α-Al. This work also aims to study how grain refinement affect the primary α-Al which is commonly used to improve the quality of castings. To be able to perform this study, both practical and theoretical work has been implemented. The casting process involved making of ladles and preparation of various equipment. The cast samples were then prepared by standard metallurgy procedure for optical analyse of the microstructure. A special etching reagent was used to analyse the microstructure in a microscope. The etching is called Weck’s reagent and its purpose is to differentiate the growth layer from the primary α-Al. The growth layer is formed during quenching and by excluding it, the calculation of the slurry’s primary α-Al becomes more precise. This is because the slurry is not quenched before it is inserted into the high pressure die casting machine, therefore no growth layer is formed. To analyse the cast samples, a special program was used to identify and to calculate the solid fraction, shape and size of the primary α-Al. The result from the calculations made by the program gave different tendencies when changing the EEM amount. The stirring rate showed a tendency to decrease the solid fraction and increase the shape factor. The superheat decreased the solid fraction and increased the shape factor. The grain refinement also decreased the solid fraction and increased the shape factor. There was no clear tendency showing that the equivalent circular diameter of the primary α-Al was affected by any of the parameters.
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Heydari, Farhad. "Mechanisms of sand flow and compaction in core-blowing." Thesis, University of Warwick, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357857.
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Kirma, Turgut. "Production Of Coal Crusher Hammer Heads By Bi-metal Casting." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/2/12609925/index.pdf.
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In this study, by considering different mechanical properties such as wear resistance and toughness of two different metal alloys in design and production stages, bi-metal casting technique was used for producing composite material which will be a solution for the cracking and wear problem in coal crushing hammer heads. The failure analysis of the classical hammer heads which are made from Hadfield steels (austenitic steel) showed that there are crack formations through austenitic grains and also the phase transformation from austenite to martensite is not completed until the material consumed its life.
Thermal analysis is the basic technique in this study to determine the solidification conditions. By using thermocouples with a suitable set-up, the cooling curves of the materials which were used in bi-metal casting had been taken and analysed. By using these cooling curve data with a written software program which is based on Newton Thermal Analysis, the solid fraction values by time and by temperate were obtained. According to these values, the interface was investigated by changing experimental conditions and solid fractions. At the last part of the study, a new approach was tried in white cast iron production.
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Soderhjelm, Carl. "Multi-Material Metal Casting: Metallurgically Bonding Aluminum to Ferrous Inserts." Digital WPI, 2017. https://digitalcommons.wpi.edu/etd-dissertations/174.
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Properties of cast aluminum components can be improved by strategically placing ferrous inserts to locally improve properties such as wear resistance and stiffness. A cost-effective production method is to cast-in the insert using the solidification of the molten aluminum as a joining method. Metallurgically bonding between the metals could potentially improve both load and heat transfer across the interface. The metallurgical bond between the steel and the aluminum has to be strong enough to withstand stresses related to solidification, residual stresses, thermal expansion stresses, and all other stresses coupled with the use of the component. Formation of a continuous defect free bond is inhibited by the wetting behavior of aluminum and is governed by a diffusion process which requires both energy and time. Due to the diffusional nature of the bond growth in combination with post manufacturing heat treatments defects such as Kirkendall voids can form. The effect of aluminum alloying elements during liquid-solid bond formation in regards to microstructural changes and growth kinetics has been described. A timeframe for defect formation during heat treatments as well as microstructural changes has been established. The effect of low melting point coatings (zinc and tin) on the nucleation of the metallurgical bond has been studied as well the use of a titanium coating for microstructural modification. A set of guidelines for successful metallurgical bonding during multi- material metal casting has also been constructed.
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Su, Xiuling. "Computer Aided Optimization of an Investment Bi-Metal Casting Process." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin998405696.
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Gelder, Andrew. "Lithium-aluminium casting alloys and their associated metal-mould reactions." Thesis, Aston University, 1992. http://publications.aston.ac.uk/9775/.
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Aluminium - lithium alloys are specialist alloys used exclusively by the aerospace industry. They have properties that are favourable to the production of modern military aircraft. The addition of approximately 2.5 percent lithium to aluminium increases the strength characteristics of the new alloys by 10 percent. The same addition has the added advantage of decreasing the density of the resulting alloy by a similar percentage. The disadvantages associated with this alloy are primarily price and castability. The addition of 2.5 weight percent lithium to aluminium results in a price increase of 100% explaining the aerospace exclusivity. The processability of the alloys is restricted to ingot casting and wrought treatment but for complex components precision casting is required. Casting the alloys into sand and investment moulds creates a metal - mould reaction, the consequences of which are intolerable in the production of military hardware. The primary object of this project was to investigate and characterise the reactions occurring between the newly poured metal and surface of the mould and to propose a method of counteracting the metal - mould reaction. The constituents of standard sand and investment moulds were pyrolised with lithium metal in order to simplify the complex in-mould reaction and the products were studied by the solid state techniques of powder X-Ray diffraction and magic angle spinning nuclear magnetic resonance spectroscopy. The results of this study showed that the order of reaction was: Organic reagents> > Silicate reagents> Non silicate reagents Alphaset and Betaset were the two organic binders used to prepare the sand moulds throughout this project. Studies were carried out to characterise these resins in order to determine the factors involved in their reaction with lithium. Analysis revealed that during the curing process the phenolic hydroxide groups are not reacted out and that a redox reaction takes place between these hydroxides and the lithium in the molten alloys. Casting experiments carried out to assess the protection afforded by various hydroxide protecting agents showed that modern effective, protecting chemicals such as bis-trimethyl silyl acetamide and hexamethyldisilazane did not inhibit the metal - mould reaction to a sufficiently high standard and that tri-methylchlorosilane was consistently the best performer. Tri-methyl chlorosilane has a simple functionalizing mechanism compared to other hydroxide protecting reagents and this factor is responsible for its superior inhibiting qualities. Comparative studies of 6Li and 7Li N.M.R. spectra (M.A.S. and `off angle') establish that, for solid state (and even solution) analytical purposes 6Li is the preferred nucleus. 6Li M.A.S.N.M.R. spectra were obtained for thermally treated laponite clay. At temperatures below 800oC both dehydrated and rehydrated samples were considered. The data are consistent with mobility of lithium ions from the trioctahedral clay sites at 600oC. The superior resolution achievable in 6Li M.A.S.N.M.R. is demonstrated in the analysis of a microwave prepared lithium exchanged clay where 6Li spectroscopy revelaed two lithium sites in comparison to 7Li M.A.S.N.M.R. which gave only a single lithium resonance.
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Karantzalis, Alexander E. "Characterisation of AI MMCs manufactured by a flux casting process." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243346.
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FORNO, ILARIA. "Investment Casting of Precious Metals: Materials and Methods." Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2502741.
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Aim of this work is the analysis of the materials and parameters related to the investment casting process,mainly focusing on peculiarities and criticisms of the casting of precious metals in jewelry production.Precious metals casting is traditionally and historically targeted to overcoming limitations in terms of geometries and final quality of the cast part. Moreover, an increasing interest rises concerning the use of new technologies and the industrializations of typical handcraft skills. New materials are therefore introduced into the process, in order to be able to get thin and intricate shapes, hollow parts and innovative design features. This is leading to a substantial rearranging of the process, with a constant innovation regarding technologies and medication of traditional materials. Considering the whole process, nvestment casting is dealing with a wide range of materials, from metallic, polymeric and ceramic classes. All these materials cannot be considered as single identities, but their synergetic behavior has to be studied, not just meaning that all of them contribute to the final quality of the cast part, but taking into account possible mutual interdependencies.
The research work has been divided in a preliminary analysis of the process, in order to deepen the knowledge about material features, and in a extended study on the application of competences deriving from other sectors to the specific one. In fact it’s almost impossible to find sector boundaries between jewelry and fashion accessories both in terms of process and in terms of market. Therefore the analysis of the state of the
art has been widened to other processes and applications, in particular focusing on fashion accessories and eyewear component production. Market analysis clearly show a high interest of jewelry towards innovative processes/materials, often deriving from completely different fields of application. For this reason, an analysis of the investment casting
process applied in the automotive and biomedical sectors can give valuable hints for the jewelry production optimization.
Particular attention has also been paid to fluid dynamic analysis of the casting system, considering metal flow into the flask and following cooling and solidification. For this purpose, computational fluid dynamic has been applied to the process. Material analysis, needed for both the simulation and for a complete understanding of the process, has been carried out. Physical and thermal properties of metals and investment materials have been analyzed in order to get a proper database for casting simulation. Waxes and resins have been tested both in terms of thermal, mechanical and chemical characteristic, in order to understand their respective roles into the process and try to optimize them. Following the analysis, process implementation has been performed in order to apply information deriving
from experimental tests to the process. Many parameters can be taken into account when optimizing precious metal casting; in order to focus the research activity, some limitation in terms of process have been applied.
Casting trails were conducted using a static vacuum casting machine on sterling silver and 18 kt. Gold alloys, referring to traditional investment casting process.
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Ha, H. U. "Squeeze casting of magnesium-based alloys and their metal matrix composites." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383410.
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Kurtoglu, Aziz. "Aluminum Oxide And Titanium Diboride Reinforced Metal Matrix Composite And Its Mechanical Properties." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605381/index.pdf.
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This study is on the production and testing of an aluminum metal matrix composite. Metal Matrix Composites can be produced in several different ways. In this study, an aluminum matrix composite is produced by direct addition of the reinforcement ceramic into the liquid metal. The ceramic reinforcement for this process was a mixture of TiB2 and Al2O3 which was produced by means of a thermite reaction of reactants Al, B2O3 and TiO2 all in powder form with their respective stoichiometric amounts. This ceramic mixture was ground to fine powder size and then added to liquid aluminum in small percentages. After casting and taking samples of unreinforced alloy and reinforced alloys, their tensile strength and hardness as material properties were measured and compared. Another issue is the wetting of ceramic particles by molten Aluminum. The aim of the experiments in general is to find a better way to produce a composite material with desired mechanical properties.
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Kennedy, Andrew Richard. "The redistribution of reinforcements during the solidification processing of metal matrix composites." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307106.
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Mertz, Andreas. "The provision of a knowledge base for product assurance for pressure die casting." Thesis, Teesside University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239125.
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Trovant, Michael. "A boundary condition coupling strategy for the modeling of metal casting processes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0011/NQ35346.pdf.
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Cao, Xinjin. "Heat treatment of liquid metal : precipitation and sedimentation processing of liquid Al-11.5Si-0.4Mg alloy." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369168.
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Etienne, Caron. "Secondary cooling in the direct-chill casting of light metals." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/5237.
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The Direct-Chill (DC) casting process is used in the non-ferrous metals industry to
produce ingots, blooms and cylindrical billets. During DC casting, primary cooling in the mould
is followed by secondary cooling, in which the cast product surface is directly cooled by water
jets. The formation of defects during the direct-chill casting process can be reduced by
controlling the heat extraction in the secondary cooling zone during the start-up phase. The
control and optimization of this process requires an accurate knowledge of the boundary
conditions and their relationship with casting parameters.
This research project studied the effect of different parameters on the heat transfer in the
secondary cooling zone of the direct-chill casting process. This process was simulated by
quenching instrumented samples of industrial DC-cast aluminum AA5 182 and magnesium
AZ3 1 with water jets and recording the thermal history within the sample using sub-surface
thermocouples. An inverse heat conduction algorithm specifically developed for this research
project converted this thermal history into surface heat fluxes and surface temperatures. The
relationship between heat flux and surface temperature was expressed by a boiling curve.
Cooling experiments showed the influence of the cooling water flow rate on
characteristic features of the boiling curve. The effect of thermophysical properties, initial
sample temperature and water temperature on high temperature boiling regimes was also
quantified. The influence of other parameters such as the water jet velocity and the surface
roughness was determined in a qualitative fashion.
Results from the quench tests were used as boundary conditions in a finite element
model for the direct-chill casting of AZ3 1 billets. Simulations of the process start-up phase
showed the critical role played by stable film boiling and water film ejection in determining the
thermal history within the billet.
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Moussa, Nadine. "Multi scale modelling and numerical simulation of metal foam manufacturing process via casting." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC021/document.
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L'objectif est d'élaborer un nouveau procédé de fabrication de mousses métalliques par voie de fonderie en modélisant l'infiltration et la solidification d'un métal liquide dans un milieu poreux. La modélisation est faite en deux étapes.Tout d'abord, à l'échelle locale un brin de la mousse métallique est considéré comme un tube capillaire et l'infiltration et solidification d'un métal liquide dans un moule cylindrique est étudiée. Deuxièmement,le modèle macroscopique de la solidification diffusive d'un métal liquide dans un milieu poreux est obtenu par prise de moyenne volumique. Le modèle local est codée dans un outil CFD opensource et trois études paramétriques ont été faites permettant la détermination des relations de la longueur et le temps d'infiltration en fonction de paramètres de fonctionnement. La modélisation de la solidification d’un métal liquide dans un milieu poreux est simplifié en considérant que le moule est complètement saturé par un métal liquide au repos,par suite la solidification se produit par diffusion pure (pas de convection). L'équilibre thermique local (LTE) est considéré entre les phases solide et liquide du métal tandis qu'un non équilibre thermique local (LTNE) est retenue entre la phase métallique et le moule. Les problèmes de fermeture associés ainsi que le problème macroscopique ont été résolus numériquementThe objective of this work is to elaborate a new manufacturing process of metal foams via casting by modelling the infiltration and solidification of liquid metal inside a porous medium.However, due to the complexity of this problem the study is divided into two steps. First, at local scale one strut of the metal foam is considered as a capillary tube and the infiltration and solidification of liquid metal inside a cylindrical mould is studied. Second, a macroscopic model of diffusive solidification is derived using the volume average method. The local model is coded in an open source CFD tool and three parametric studies were done where the relations between the infiltration length and time as function of the operating parameters are determined. The modelling of the solidification of liquid metal inside a porous medium is simplified by considering that the mould is fully saturated by liquid metal at rest, solidification occurs by pure diffusion. Local thermal equilibrium (LTE) is considered between the solid and liquid phases of the metal while local thermal non equilibrium (LTNE) is retained between the metallic mixture and the mould. The associated closure problems as well as the macroscopic problem were numerically solved