3-DIMENSIONAL MODELING OF THERMAL RESIDUAL-STRESSES AND MECHANICAL-BEHAVIOR OF CAST SIC AL PARTICULATE COMPOSITES/

Thermal residual stresses developed during casting of SiC/aluminum par ticulate-reinforced composites were investigated as a function of cool ing rate and volume fraction of particles using thermo-elastoplastic f inite element analysis. The phase change of the matrix during solidifi cation and the temperature-dependent material properties as the compos ite is cooled from the liquidus temperature to room temperature were t aken into account in the model. Further, the effect of thermal residua l stresses on the mechanical behavior of the composites was also studi ed. Based on the study, it was found that the matrix undergoes signifi cant plastic deformation during cool down and has higher residual stre ss distribution as the cooling rate increases. The model which does no t include the solidification of the matrix tends to overestimate the r esidual stresses in the matrix and underestimate the tensile modulus o f elasticity of the composites. In addition, the presence of thermally induced residual stresses tends to decrease the apparent modulus of e lasticity and increase the yield strength of the composites compared t o those without residual stresses.