AN FEM STUDY OF THE PLASTIC-DEFORMATION PROCESS OF WHISKER REINFORCED SIC/A1 COMPOSITES

The finite element method (FEM) was employed to investigate the matrix plastic flow in a whisker reinforced SiC/Al composite under external tensile load. It was found that the plastic zone induced by the plastic relaxation of thermal stresses expands under the external tensile load. The overall matrix plastic flow was characterized by the expansion and interconnection of the plastic zones around whiskers. This process can be divided into several characteristic stages, and related to the global stress-strain relationship. It also indicated that the strengthening was due mainly to the thermally induced matrix work hardening at the tip of the whisker. Finally, the initiation of plastic flow in an inhomogeneously reinforced composite was governed by the redistribution of the average stress and strength in the reinforcement clusters.