纤维增强金属基复合材料的应力集中及力学性能

STRESS CONCENTRATION AND MECHANICAL BEHAVIOURS OF FIBER / METAL COMPOSITES

本文提出了一种多裂纹模型，用此模型可以分析复合材料中的应力集中、界面脱粘、基体屈服及裂纹间交互作用，分析结果表明，在纤维中存在着较高的应力集中．基体屈服及反应层中裂纹密度增加都促进应力集中，而界面脱粘则使应力集中松驰．对于涂ＳｉＣ涂层的Ｃ／Ａｌ复合材料，最佳界面结合强度在１００—３００ＭＰａ之间．

A multi-crack-interaction model has been proposed for analysis of the mechanical behaviours of metal-matrix composites reinforced by coated fibers. The stress concentrations and non-elastic effects such interface debonding and matrix yielding caused by the cracks can be calculated on the model. The result shows that there is high stress concentration in the fiber, which increases with increasing the matrix yielding width and the density of the cracks in the reaction zone, but decreases after interface debonding. There exists an optimum interfacial bonding with which the composites obtain the maximum strength. The optimum interfacial shear strength for SiC-coated C / Al composites is in the range of 100─300 MPa