颗粒形状、含量和基体特性对金属基复合材料压缩力学行为的影响

通过建立轴对称体胞模型,用数值分析手段研究了在变形速率范围10－4~105/s内,陶瓷颗粒增强铝合金复合材料的压缩塑性流变特征,讨论了不同颗粒形状(圆柱形和球形),不同颗粒体积含量(10％~50％)和不同铝合金基体(LC4、LY12CZ和7075)对金属基复合材料流动应力、应变率敏感性等的影响,构造了可以描述高应变率下金属基复合材料压缩行为的本构模型,并考虑了基体特性、颗粒形状、体积含量及应变率的影响,得出了与试验相吻合的结果。

INFLUENCES OF PARTICLE SHAPE, VOLUME FRACTION AND MATRIX MATERIALS ON THE COMPRESSIVE BEHAVIOR OF MMCs

The compressive plastic deformation of particle-reinforced metal-matrix composites was investigated through numerical modeling at high strain rates. The numerical modeling is performed using axisymmetric unit cell model, with the particles treated as elastic ellipsoids or cylinders embedded within a visco-plastic matrix. Five particle volume fractions from 10% to 50% and three aluminium matrix materials LY12CZ, LC4 and 7075 were analyzed. The results show that the flow stress increases with the increasing of strain rate and the volume fraction of the reinforcement. The flow stress increases more for the higher strain hardening matrix material and for the cylindrical reinforcement. The strain rate sensitivity is also related to the matrix material and the particle shape. A simple analytical model is introduced which is able to describe the features of the computational predictions to a certain extent, which is in good agreement with the experimental results.