Automating the Design Process and Powder Processing of Functionally Gradient Materials

Abstract

Abstract There is great deal of interest in Functionally Gradient Materials (FGMs) as evidenced by three recent international conferences on the subject (Yamanouchi, et al., 1990, Holt, et al., 1993 and Ishner and Cherradi, 1994). Similar to composites, FGMs are microscopically inhomogeneous. However, unlike most composites, macroscopic inhomogeneities are designed into FGMs. This is achieved by continuously varying the volume fraction of the second phase in a controlled manner. Thus, the distribution of the second phase has ‘to be designed’ based on the type of application and geometry of the structure. In addition, their inhomogeneous nature causes non-uniform shrinkage and cracks during processing before FGMs are ever put into service. Accordingly, two independent research programs are in progress on FGMs at Michigan State University; (1) fabrication technology and (2) design process management tools. On the former program, powder fabrication protocols are being developed to reduce processing-induced residual stresses. On the latter program, in a benchmark study for the framework developed by Baldwin and Chung (1995), the complete design process for axisymmetric FGMs cylinders is implemented.