初始组织对热挤压Mg-6Al-2Ca-2Sm合金显微组织和力学性能的影响

Effect of Initial Microstructure on Microstructure and Mechanical Properties of Hot Extruded Mg-6Al-2Ca-2Sm Alloy

对铸态Mg-6Al-2Ca-2Sm合金分别进行经固溶和固溶+时效处理获得不同初始组织试样,然后对不同初始组织的试样进行热挤压,研究了不同初始组织对热挤压Mg-6Al-2Ca-2Sm合金显微组织和力学性能的影响。结果表明:铸态合金经热挤压后发生明显的部分再结晶,显微组织得到显著细化;经固溶或固溶+时效处理能够改善合金组织,热挤压后合金显微组织分布更加均匀。初始组织分布能够改善热挤压Mg-6Al-2Ca-2Sm合金室温和高温力学性能,固溶+时效后进行热挤压的Mg-6Al-2Ca-2Sm合金具有更高的抗拉强度和延伸率。与铸态进行挤压的Mg-6Al-2Ca-2Sm合金相比,固溶+时效后进行热挤压Mg-6Al-2Ca-2Sm合金的室温抗拉强度和延伸率分别提高6.1%和14.5%,高温抗拉强度和延伸率分别提高11%和8.3%。

The as-cast Mg-6 Al-2 Ca-2 Sm alloys were heat treated by solid solution and solid solution+aging treatment;then the samples with different initial microstructures were obtained,on which hot extrusion was performed.Effect of different initial microstructures on the microstructure and mechanical properties of hot-extruded Mg-6 Al-2 Ca-2 Sm alloy was studied.The results show that the Mg-6 Al-2 Ca-2 Sm alloy undergoes obvious partial recrystallization after hot extrusion,and the grain is significantly refined;solid solution or solid solution+aging treatment can improve the distribution of metallic phases,and the precipitated phase distribution after hot extrusion is more uniform.The heat treatment before extrusion can improve the mechanical properties of the hot extruded Mg-6 Al-2 Ca-2 Sm alloy at room temperature and high temperature.And the solid solution+aging treated alloy after hot extrusion has the highest tensile strength and elongation among all these samples.Compared with the properties of as-cast Mg-6 Al-2 Ca-2 Sm alloy after hot extrusion,tensile strength and elongation of the solution+aging treated alloy after hot extrusion are increased by 6.1%and 14.5%at room temperature,and by 11%and 8.3%at high temperature,respectively.