微结构对金属基复合材料宏观弹塑性性能的影响

采用广义自洽有限元迭代平均化方法分析ＳｉＣ晶须增强铝基复合材料的弹塑性拉伸行为，研究纤维长径与体分比的变化对复合材料宏观弹塑性变形的影响。通过细观应力场的分析，讨论基体内塑性区的发展与复合材料宏观弹塑性变形过程之间的联系，指出纤维端头处基体塑性区的发展将对复合材料拉伸弹塑性行为有着显著影响。最后，还讨论了以名义屈服应力σ０．２来表征金属基复合材料的弹塑性特征的不足之处。

EFFECTS OF MICROSTRUCTURE ON THE MACROSCOPIC ELASTO-PLASTIC PROPERTIES OF METAL MATRIX COMPOSITES

The generalized selfconsistent finite-element iterative averaging method was adopted to analyze the elastoplastic tensile properties of SiC whisker reinforced aluminum aluminum matrix composites.The effects of varying fiber's aspect ratio and volume fraction on the macroscopic elastoPlastic deformation of the composites were studied.By the analysis of microscopic Stress fields,the relation between the propagation of the elasto-plastic region in the matrix and the macroscopic elastoplastic deformation of composites was discussed.It was found that the propagation of the plastic region in the matrix between the fiber's ends would affect prominently the elato-planic tensile behaviour of the composites.It was shown that the characterization of the stress-strain response interms of the 0.2% offset yield strength is incomplete.