颗粒尺寸对颗粒增强型金属基复合材料动态特性的影响

INFLUENCE OF PARTICLE SIZE ON THE DYNAMIC BEHAVIOR OF PMMCs

利用有限元模型分析了颗粒增强型金属基复合材料(PMMCs)Al/SiC的颗粒尺寸对复合材料在不同应变率下的动态特性的影响。采用有限元三维立方体单胞模型嵌入单个和多个球形增强颗粒,颗粒直径分别为16μm和7.5μm,多颗粒模型内部颗粒随机分布。基体材料假设为弹塑性,应变强化及应变率强化均符合指数规律。模拟结果表明:颗粒尺寸、颗粒体积含量及应变率对金属基复合材料的动态特性的影响是相互耦合的。颗粒体积含量一定时,颗粒尺寸越小,复合材料流动应力越高;颗粒含量越高,材料流动应力越高;应变率越高,材料流动应力越高。

The influence of particle size on the dynamic behavior of particle-reinforced metal-matrix composites was investigated through the finite element method under different strain rates. The three-dimensional cubic unit cell models which contained one or several SiC particles were employed. The diameters of the particles were 16μm and 7. 5 μm, separately. And the arrangement of the multi particles inside the unit cell mode was random. The stress- strain behavior of the matrix material is assumed to be power-law strain hardening and coupled with power-law strain rate hardening. The simulation results show that the influence of particle size on the dynamic behavior of PMMCs is coupled with the volume fraction of the particle and the strain rate. The smaller the diameter of the particle, the better the reinforced effect, when the volume fraction of the particles is constant. The flow stress increases with the increasing of the particle volume fraction and strain rates.