SiCw/Al复合材料的拉伸性能与变形行为

TENSILE PROPERTIES AND DEFORMATION BEHAVIOR OF SiCw/Al COMPOSITE

本文对SiCw/6061Al复合材料进行了拉伸试验和断口分析。结果表明,该材料具有与基体合金大致相同的比例极限,但却具有高的加工硬化率,其抗拉强度远高于基体合金。复合材料低的比例极限可由晶须端部应力集中所导致的低应力局部塑性变形来解释。高的加工硬化率则与变形过程中复合材料基体中的位错大量增殖及晶须裂纹扩展的阻碍作用有关。由细小韧窝组成的复合材料断口表征了塑性变形的局部性。

In this paper the tensile tests of SiCw/6061Al composite were carried out, and the fracture surfaces were analysed by SEM technique. It was found that the proportional limit of the composite and the matrix alloy was approximately same, but the composite exhibited higher work-hardening rate and much higher tensile strength compared to the matrix alloy. The low proportional limit may be explained by localized plastic deformation under low macroscopic stress caused by stress concentrations at the ends of SiC whiskers. High work-hardening rate is related ton pronaunced increase in the dislocation density in the matrix during deformation and whiskers prohibition of microcrack propagation. The fracture surface of the composite consisted of fine dimples indicates the localization of plastic deformation.