Finite Element Methods to Optimize by Factorial Design the Solidification of Cu-5wt%Zn Alloy in a Sand Mold

Abstract

Throughout the manufacturing industry, casting process simulation has been widely accepted as an important tool in product design and process development to improve yield and casting quality. Casting simulation requires high-quality information concerning thermo-physical and physical properties during solidification. Some properties have been measured for specific alloys, but the number of alloys for which information is available is limited. Furthermore, the information may be incomplete in the sense that not all properties have been measured and sometimes, disparate information from a variety of sources is used to build up the database for one specific alloy. To overcome the lack of data and achieve a better understanding of how changes in composition within a specification range of an alloy may affect solidification properties, it is highly desirable to develop experimental techniques or computer models for calculation of the thermo-physical and physical properties of multicomponent alloys for the process of reliable solidification (Guo et al., 2005). The computer simulation of cooling patterns in castings has done much to broaden our understanding of casting and mold system design. The structural integrity of shaped castings is closely related to the time–temperature history during solidification, and the use of casting simulation could do much to increase this knowledge in the foundry industry. (Ferreira et al., 2005). The ability of heat to flow across the casting and through the interface from the casting to the mold directly affects the evolution of solidification and plays a notable role in determining the freezing conditions within the casting, mainly in foundry systems of high thermal diffusivity such as chill castings. Gravity or pressure die castings, continuous casting and squeeze castings are some of the processes where the product’s soundness is more directly affected by heat transfer at the metal/mold interface (Ferreira et al., 2005). According to the authors Atwood and Lee (Atwood & Lee, 2003), the mechanical properties of metal products depend upon the phenomena occurring during production. Defects formed during each stage of production can persist or modify the behavior of the metal during subsequent processing steps. Therefore, ensuring that an appropriate microstructure is formed at each stage with minimal defects has always been a focus in the study of metal production. In aluminum alloy shape castings, the final microstructure is directly dependent upon the as-cast microstructure since the only post-casting processing is normally a heat treatment. One microstructural feature that can affect the final properties of aluminum alloy