中文摘要：

为研究相对密度对泡沫镁合金动态力学性能与吸能特性的影响，利用分离式霍普金森压杆（SHPB）装置对不同密度的泡沫镁合金进行动态力学性能测试。研究结果表明：随着相对密度的增大，泡沫镁合金的屈服强度、平台应力显著增加，致密应变相应减小。通过拟合，得到材料屈服强度与相对密度的关系式。运用单位体积吸能量、吸能效率和理想吸能效率表征了材料的吸能特性。相对密度在一定范围内越大，泡沫镁合金的单位体积吸能量越高，吸能效率略有降低，但稳定在0．3左右。随着相对密度的增加，材料最大吸能效率所对应的应力值增大。泡沫镁合金的理想吸能效率值可达0．9，这表明该材料是一种吸能防护性能好的材料。

英文摘要：

The effects of relative density of magnesium alloy foams on their dynamic mechanical properties and energy absorption characteristics are investigated. Split Hopkinson pressure bar （SHPB） is used to evaluate the dynamic compressive behaviors of magnesium alloy foams with different densities. The exper- imental results show that, with the increase in relative density, the yield stress and platform stress in- crease significantly while the densification strain decreases. Based on the experimental results, the fitting equations of yield stress and relative density are obtained. The energy absorption properties of metal foams are characterized by energy absorption per unit volume, energy absorption efficiency and ideal energy ab- sorption efficiency. The higher the relative density of magnesium alloy foams is within a certain range, the higher the energy absorption capacity per unit volume is. The energy absorption efficiency decreases slightly, but it is steady at about 0.3, while the stress corresponding to the highest absorption efficiency increases. Magnesium foam is a kind of material with better protective performance, with the ideal energy absorbing efficiency reaching 0.9.