Al/Al_2O_(3P)金属基复合材料的静动态压缩性能及损伤分析

Damage analysis and quasistatic and dynamic compression properties of Al/Al_2O_(3P) MMC_S

用气压浸渗工艺制备了体积分数 4 0 %～ 5 0 %Al2 O3 颗粒增强铝基复合材料 ,使用了四种不同尺寸的Al2 O3颗粒 ,其平均粒径分别为 5、10、30和 6 0 μm。测定了这些复合材料的静、动态压缩性能 ,并通过材料压缩前后密度变化的测量 ,定量表征了材料的累计损伤。结果表明 ,与基体材料相似 ,这些复合材料表现了明显的应变率敏感性 ;当增强颗粒平均粒径小于 6 0 μm时 ,材料的累计损伤基本与应变率无关 ,主要取决于材料的应变。材料中颗粒的破裂主要是由颗粒间的作用引起的。较小尺寸颗粒增强的复合材料具有较高的流动应力和较小的累计损伤 ,并随着颗粒体积分数的增加 ,材料的流动应力和损伤率都相应增加。

Pure aluminium matrix composites reinforced with 44-55 vol.% Al 2O 3 particles of various sizes are produced by gas-pressure infiltration. Quasistatic and dynamic compression test results of the composites are measured. The accumulation of damage in the composites is quantified through high-precision density measurements before and after compression. Test results show that, similar to matrix material, the composites have obvious strain-rate sensitivity. When the mean particle size smaller than 60μm, the damage accumulation has nothing to do with strain-rate and primarily depend on strain. Damage in the particle is originated by interact among particles. Composites reinforced by smaller particles have high flow stress and accumulate less damage, while a greater volume fraction of reinforcement increases the flow stress and the rate of damage accumulation.