应变率对SiC颗粒增强铝基复合材料拉伸性能的影响

本文利用岛津试验机和自行研制的冲击拉伸试验装置，对体积含量为10%的SiC颗粒增强铝基复合材料进行了准静态的拉伸试验、冲击拉伸试验和冲击拉伸加卸载试验，获得了复合材料在应变率为0.002s^-1-1000s^-1范围内从弹塑性变形直至断裂的完整应力应变曲线。试验结果表明，随着应变速率的提高，复合屈服应力，拉伸强度以及破坏应变均相应提高，具有明显的应变率强化效应和高速韧性现象；同时，由于冲击拉伸试验过程中热力耦合效应的影响，准静态加载下复合材料的应力指数与冲击拉伸加载下复合材料的应力指数相比降低了17.8%；在用冲击拉伸复元试验解耦出热力耦合效应的影响后，材料的静、动态等温应力应变曲线具有相同的应变硬化规律。最后，根据复合材料在不同应变率下的试验结果和Eshelby‘s等效夹杂理论，本文建立了一个计及应变率强化效应的弹塑性自洽模型，模型拟合结果与试验结果吻合得很好。

Effect of Strain Rate on Tensile Behavior of SiCp/AI MMC

In the present paper, the loading and loading-unloading tests of SiCp/Al (SiC particle reinforced Al alloy matrix) composite have been carried out by a self-designed tensile impact apparatus, and the quasi-static tensile tests have been performed on the Shimadzu-5000 testing apparatus. The stress/strain curves of composites in strain rate range from 0.002s-1 to 1000s-1 have been obtained. The experimental results show that the SiCp/Al composite is a rate-sensitive material, the yield strength, ultimate strength and failure strain are all increased with the increasing of strain rate. The experimental results also show that the value of static stress exponent M is 17.8% lower than that of M at high strain rate. On the basis of these experimental results and Eshelby' s equivalent inclusion method, a self-consistent model has been developed to predict non-linear deformation of SiCp/Al at different strain rate. The comparison between the model calculation and experimental results for the strain rate dependence of SiCp/Al shows good agreement.