Mg-12Gd-2Y-0.5Zr合金的高温蠕变行为

High Temperature Creep Behavior of Mg-12Gd-2Y-0.5Zr Magnesium Alloy

研究了Mg-12Gd-2Y-0.5Zr系镁合金的高温蠕变行为。结果表明，试验合金的蠕变抗力普遍优于WE54合金，在50~70 MPa的应力范围内，200 ℃时应力指数n在2.5~3.8之间，300 ℃时n在4.2~6.1之间，该系列合金的蠕变主要由位错攀移控制向位错交滑移控制机制转变；在200~300 ℃的温度范围内，50 MPa条件下蠕变激活能Qc为66 kJ/mol，70 MPa条件下蠕变激活能Qc为87.2 kJ/mol之间。随着温度和应力的增加，与纯镁的晶界扩散激活能（80 kJ/mol）越来越接近。

The creep behavior of Mg-12Gd-2Y-0.5Zr magnesium alloy at high temperature was analyzed. The results show that the creep resistance of the experimental alloy is generally superior to that of com- mercial WE54 alloy, and the stress exponent（n） is in range of 2.5-3.8 at 200 ℃and 4.2-6.1 at 300 ℃under a stress of 50-70 MPa. The creep mechanisms of the series alloy mainly are controlled by dislocation climbing towards dislocation cross-slip. The creep activation energy（Qc） is 66 kJ/mol under 50 MPa and 87.2 kJ/mol under 70 MPa at 200-300 ℃. With the increase of temperature and stress, creep activation energy of Mg-12Gd-2Y-0.5Zr alloy is near to diffusion activation energy （80 kJ/mol） of pure magnesium more and more.