THE EFFECT OF PARTICLE SHAPE ON DUCTILITIES OF SiC_p/LD2 COMPOSITES

Blunted SiC particles were selected as reinforcement to fabricate SiC./LD2 composites. Compared with a general SiC particle,the blunted SiC. reinforced composite has higher ductility.Analysises of finite element method(FEM) and tensile fractographic scanning electron microscope(SEM)show that particle fracture is the main failure mechanism of composites after T6 treatment.The ductility improvement of processed SiCp/LD2 is attributed to decrease the heat-residual-strain concentration near penetrating particle corner and the possibility of penetrating particle corner fracturing at low level of external strain when the penetrating particle corner has been blunted. The main failure mechanism of composites after extruded but no T6 treatment is matrix failure. Therefore, extent of ductility improving of composites after T6 treatment is higher than that of composites after extruded.