不同固溶状态Mg-10Gd-3Y-1.2Zn-0.5Zr合金的力学性能及断裂行为

Influence of Different Solution Treatments on Mechanical Properties and Fracture Behavior of Mg-10Gd-3Y-1.2Zn-0.5Zr Alloys

通过在Mg-10Gd-3Y-0.5Zr合金中添加少量Zn制备出一种新型Mg-10Gd-3Y-1.2Zn-0.5Zr合金,并利用扫描电子显微镜、拉伸试验机分析研究Mg合金不同状态下的显微组织、力学性能及断裂行为。结果表明:Mg-10Gd-3Y-1.2Zn-0.5Zr合金在不同的时效状态下,铸态塑性差,T4态塑性好,T6态塑性优于铸态但劣于T4态,且所有样品都是从脆性解理断裂为主,晶界和层状相界面比化合物界面结合牢固。通过比较3个不同温度下T6态的力学性能,发现提高固溶温度能提高合金的强度,但延伸率会略降。并且Zn促进层状相生长,但是对基体塑性提高作用有限。

Mg-10Gd-3Y-1.2Zn-0.5Zr alloy was prepared by adding 1.2wt%Zn in Mg-10Gd-3Y-0.5Zr alloy.The microstructures and mechanical properties as well as fracture behaviors of the alloys at the different conditions were studied by using optical microscopy,scanning electron microscopy and tensile testing machine.The results indicated that the cast case showed a poor plasticity,however,T4 alloys had a good plasticity,and the plasticity of T6 state was between the cast and T4 conditions.All the specimens mainly attributed to brittle cleavage fracture,and the bonding strength at interface of grain boundary and lamellar phase was stronger than the compound interface.Compare to the T6 mechanical properties at three different temperatures,it was found that improving solution temperature could improve the alloy strength,however,the elongation rate reduced slightly.The Zn can promote the growth of lamellar phase,however,only a limited role for plastic characteristics of the matrix could be observed.