颗粒尺寸对SiC_p/Mg复合材料热膨胀性能的影响

Effect of Particle Size on Thermal Expansion Behavior of High Volume Fraction SiC_p/Mg Composites

设计并采用真空气压浸渗法制备了不同颗粒尺寸的高体积分数SiCp/AZ91D镁基复合材料,研究了颗粒尺寸对镁基复合材料热膨胀性能的影响。结果表明,改变颗粒尺寸是调节镁基复合材料热膨胀性能的一种非常有效的手段。相同体积分数复合材料的热膨胀系数随颗粒尺寸的减小而逐渐降低,不同体积分数的SiCp复合材料的热膨胀系数与复合材料的界面面积成反比关系;减小颗粒尺寸与提高颗粒体积分数一样,能有效降低复合材料的热膨胀系数;颗粒尺寸对镁基复合材料热膨胀性能的作用机制主要是通过复合材料的界面面积、致密度及其镁基体的位错密度来实现的。

High-volume fraction SiCp/Mg composites with different particle sizes were fabricated by vacuum-pressure infiltration technology,and the effects of SiC particle size on thermal expansion behavior of SiCp/Mg composites were examined.The results indicate that the particle size has the significant effect on the coefficient of thermal expansion（CTE）,and at the same volume fraction conditions,the CTE of the composites is decreased with the decrease of the particle size.In addition,the CTE of the composites with different volume fraction is inversely proportional to the interfacial area of the composites.CTE of the composites can be effectively decreased by decreasing the particle size and increasing the volume fraction of particle.The effect of particle size on thermal expansion behavior of the SiCp/Mg composites is attributed to acting on interfacial area,relative density of the composites as well as dislocation density of AZ91D alloy.