几何特征对SiC颗粒增强Al基复合材料力学行为的影响

利用有限元方法建立三维模型分析SiC颗粒在不同形状、不同体积分数和不同尺寸时对Al基复合材料力学行为的影响,并进行拉伸试验研究.结果表明,颗粒形状比颗粒尺寸和颗粒体积分数对材料的应力、应变分布及材料韧性的影响大.颗粒尖角附近有严重的应力集中现象,在外力方向上颗粒端部附近的基体上的应变也有集中现象.随颗粒角度的减小,颗粒的应力很快增大而韧性减小,材料的弹性模量有增大的趋势.随颗粒体积分数的增大,颗粒的应力有减小趋势,材料的弹性模量呈增大趋势.颗粒尺寸较小时(平均尺寸为5 μm),颗粒尺寸对材料的应力及应变的影响小.

Effect of Geometrical Characteristic on the Mechanical Behavior of SiC Particle Reinforced Aluminum-Matrix Composites

A three-dimension finite element model (FEM) was used to analyze the effect of particles with different shapes, volume fractions and particle sizes on the mechanical properties of SiC particle reinforced aluminum-matrix composites. The results show that the particle shape has greater effect on the stress of particle, the strain of matrix and the ductility of composites than that of the particle size and volume fraction. There are serious stress concentration round the particle corner and strain concentration in the matrix adjacent to the particle corners along the load. The stress increases quickly, the ductility decreases and the elastic modulus increases with decreasing the particle corner degree. The stress decreases and the elastic modulus increases with increasing the volume fraction of SiC particles. The particle size has little effect on the stress and strain of the composites with small particle size