高性能镁合金Mg-Dy-Gd-Zr微观组织及力学性能研究

Research on Microstructure and Mechanical Properties of High Performance Mg-Dy-Gd-Zr Alloy

以高性能镁合金Mg-Dy-Gd-Zr为研究对象,对含不同含量镝(Dy)和钆(Gd)稀土元素的两种镁合金Mg-8Dy-2Gd-0.2Zr(DG82K)、Mg-2Dy-8Gd-0.2Zr(DG28K),在不同热处理下的微观组织和力学性能进行试验分析。结果表明:镁合金微观组织为均匀分布的等轴颗粒,晶粒比较细小,合金晶粒尺寸60μm左右;随Dy元素含量增加和Gd元素含量减小,合金微观组织中α-Mg相增加,第二相却减小,且合金维氏硬度也减小;随时效时间延长,DG28K合金维氏硬度呈现先增加后减小趋势,而DG82K合金维氏硬度呈现先增加后减小再增加最后减小趋势;经T4热处理DG82K、DG28K合金抗拉屈服强度和极限抗拉、抗压强度都减小,而抗压屈服强度和伸长率都增加,而DG82K、DG28K合金压缩率分别呈现减小和增加趋势。

High performance Mg-Dy-Gd-Zr alloy was regarded as the research object, microstructure and mechanical properties of two kinds of Mg-8Dy-2Gd-0.2Zr（DG82K）, Mg-2Dy-8Gd-0.2Zr（DG28K） with different content rare earth elements of dysprosium（Dy） and gadolinium（Gd） were analyed through experiment under different heat treatment. The results show that the microstructure of magnesium alloy appears uniform distribution of axis particles, and grain size is small. Alloy grain sizes are all around 60 μm. As Dy elements increasing and Gd element decreasing, the microstructure of α-Mg phase in the alloy is increased, the second phase is reduced, and vickers hardness of the alloy is decreased; with the increase of aging time, the vickers hardness of DG28 K alloy is first increased then decreased, and the vickers hardness of DG82 K alloy is the trend of first increased and decreasing then increased and the last decreasing. After T4 heat treatment, the tensile yield strength, ultimate tensile and compressive strength of DG82 K, DG28 K alloy are reduced, and the compressive yield strength and elongation of DG82 K, DG28 K alloy are increased, while the compression ratio of DG82 K, DG28 K alloy shows a trend of decrease and increase respectively.