【摘要】 对用高压凝固铸造法(Squeeze Casting)制造的碳化硅晶须增强铝(SiCw/Al)复合材料的拉伸断口进行了扫描电镜(SEM)分析,并与作为该复合材料基体的6061铝合金做了对比试验。结果表明,SiCw/Al复合材料的断口形貌与铝合金不同,其断裂表面由细密等轴状塑变坑连成一片,高低起伏的变化是材料强化的间接反映。在断口上可观察到少量拔出或断裂的晶须。用晶须临界长径比的概念可以很好地解释复合材料在断裂时晶须很少露出表面的现象。混乱、均匀分布的晶须对基体变形有约束作用,SiCw/Al复合材料的断裂是从晶须与晶须之间铝的塑性变形和起裂开始的。更多还原

【Abstract】 The tensile fracture of a silicon carbide whisker reinforced aluminium(SiCW/Al) composite made by a squeeze casting is investigated with SEM. The expermental result compared with 6061 aluminium alloy which is used as thematrix of composite shows that fracture morphology of the composite, which is made of fine and equiaxial dimple, is different with the aluminium alloy. Same whiskers pulled out or fractured can be observed on the surface. The phenomenon that the whiskers rarely appear on the surface can be explained in terms of critical aspect ratio of the whisker when the composite is tensioned to fracture. The fracture of SiC_w/Al composite is initiated by the deformation of aluminium, that is restricted by the whiskers distributed disorderly around the whiskers,更多还原