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采用分离式霍普金森压杆(SHPB)对真空熔炼制备的Mg-Li合金进行了静、动态试验研究,试件的加载应变率范围为1.7×10-3～1026s-1,得到了材料在不同应变率下的应力-应变曲线。并根据实验结果确立了Mg-Li合金在一维应力高应变率冲击状态下的本构关系。同时还分析了不同应变率冲击后Mg-Li合金的金相组织。结果表明,该Mg-Li合金在室温下的动态冲击性能对应变率不敏感。Mg-Li合金在一维应力高应变率冲击状态下的本构关系为σ=1.5ε,(σ<0.12GPa),σ=0.12+2.7ε1.2(σ≥0.12GPa)。随着应变率的增加,晶粒尺寸先变小,再趋于不规则形状,而且晶界处分布的短条状化合物也逐渐集中。
The static and dynamic experiments of the vacuum melting Mg-Li alloy were carried out by using the split Hopkinson pressure bar (SHPB). The loading strain rate of the sample ranged from 1.7 × 10-3 to 1026s-1, Stress-strain curves at different strain rates. Based on the experimental results, the constitutive relation of Mg-Li alloy under one-dimensional stress and high strain rate impact was established. The microstructures of Mg-Li alloy after different strain rates were also analyzed. The results show that the dynamic impact properties of the Mg-Li alloy at room temperature are not sensitive to the strain rate. The constitutive relation of Mg-Li alloy under the condition of one-dimensional stress and high strain rate impact is σ = 1.5ε (σ <0.12GPa) and σ = 0.12 + 2.7ε1.2 (σ≥0.12GPa). With the increase of strain rate, the grain size first becomes smaller, and then tends to irregular shape, and the strip-like compounds distributed at the grain boundaries are also gradually concentrated.