颗粒形状对SiCp／LD2复合材料塑性的影响

采用经钝化处理的ＳｉＣ颗粒作为增强体制备的ＳｉＣｐ／ＬＤ２复合材料，与普通ＳｉＣｐ／ＬＤ２相比，材料明显提高了塑性，有限元与拉伸断口的扫描电镜分析表明，材料经Ｔ６处理后，断裂机制以颗粒断裂为主，塑性得以提高的原因主要是颗粒尖角钝化后，降低了尖角处热残余应变集中，并降低了颗粒尖角部在外加应低时断裂的可能性；而材料未经Ｔ６处理时，断裂机制以基体失效为主，塑性提高主要源于尖角处热残余应变集中的降低，因则

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.