陶瓷颗粒增强金属基复合材料的细观强度分析

Micro-Strength of Particle Reinforced Metal Matrix Composites

陶瓷颗粒增强金属基复合材料的失效主要有界面脱粘、增强粒子开裂等新的细观结构损伤机制。为了减小这些不足并对细观失效过程有一个清晰的了解,近来人们对金属基复合材料进行了大量研究,在此基础上,本文用细观力学的方法和损伤模型研究了陶瓷颗粒增强金属基复合材料的强度和损伤失效。为了计算方便,陶瓷颗粒简化为在复合材料中随机分布的椭球形粒子,然后以二相胞元模型计算分析了金属基体、颗粒中的应力应变分布情况,结果表明,基体中应力极不均匀,界面区存在应力集中,并计算了界面弧形裂纹扩展时的能量。最后分别提出了基体,颗粒和界面的失效强度准则,本文结果对于颗粒增强金属基复合材料具有普遍的实用性。

Metal matrix composites reinforced by ceramic particles have been widely applied with perfect properties,whose failure mainly results from particle-matrix interfacial debonding and particle cracking.Based on the current researches,the strength and damage of metallic matrix composites are investigated following the micromechanics view.The composites are simplified into metal matrix composites with randomly distributed ellipsoidal particles,the stress and strain distribution in the particles and matrix are evaluated.The results show that the stress gets ununiform in the matrix and stress concentration arises in the interface,then the released energy as the interface arc crack extends is calculated.The factors affecting the damage evolution and the effects of particle fraction and damage strength on damage evolution are discussed in detail to propose a criterion for failue of the matrix,particle and interface.