Mg-8Li合金动态断裂行为的加载速率效应

摘要

The dynamic fracture experiments of Mg-8％ Li alloy were carried out with the Hopkinson pressure bar, and the dynamic fracture behavior and its loading rate effects of the alloy under high-speed impact were investigated. The results show that the fracture micro-mechanism of Mg-8％ Li alloy is duetile fracture under high-speed impact condition, and there are a lot of dimples in the fracture surface.With the increase of loading rate from 14.27 m/s to 21.33 m/s, the dynamic fracture toughness of the alloy reduces gradually, and the number of secondary crack in fracture surface increases obviously to make the alloy behave brittle fracture tendency at high loading rate.%利用Hopkinson压杆技术对Mg-8%Li合金进行动态断裂实验,研究该合金在高速冲击下的动态断裂行为及其加载速率效应.结果表明:在高速冲击条件下,Mg-8%Li合金呈现韧性断裂,断口中存在大量韧窝.随冲击速度由14.27 m/s增加到21.33 m/s,Mg-8%Li合金的动态断裂韧性降低,断口中二次裂纹明显增多,从而使Mg-8%Li合金在高加载速率下表现出脆性断裂倾向.