固溶工艺对挤压态Mg-9.2Gd-1.9Y-1.8Zn-0.5Zr合金组织和硬度的影响

Effect of solution treatment process on microstructure and hardness of as-extruded Mg-9.2Gd-1.9Y-1.8Zn-0.5Zr alloy

通过差热分析(DSC)、光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)等分析手段研究了不同固溶处理工艺对挤压态Mg-9.2Gd-1.9Y-1.8Zn-0.5Zr合金微观组织和力学性能的影响。结果表明:挤压态Mg-9.2Gd-1.9Y-1.8Zn-0.5Zr合金经过固溶处理后显微组织主要由α-Mg基体、Mg_(12)Zn(Gd,Y)相、富稀土相等组成。当固溶温度达到490℃后,随着保温时间的延长,合金基体中析出规则条纹状14H-LPSO相,该相主要起到第二相强化的作用,并能显著提高试验材料的显微硬度。该合金的最佳固溶处理工艺为490℃×13 h时,其平均显微硬度最高,达到77 HV0.2。

Effects of different solution treatment processes on microstructure and mechanical properties of as-extruded Mg-9.2 Gd-1.9 Y-1.8 Zn-0.5 Zr alloy were studied by means of DSC,OM,SEM,and TEM.The results show that,after solid solution treatment the microstructure of the alloy consists ofα-Mg matrix,Mg_(12)Zn(Gd,Y)phase and phases rich in rare earth.With the increase of holding time,the regular striated LPSO phase is precipitated in the matrix when the tested alloy solution treated at 490℃,which plays an important role in second phase strengthening and remarkably improves the microhardness of the tested material.The optimum solution treatment process of the alloy is 490℃×13 h,at which the highest average microhardness of the tested alloy can reach 77 HV0.2.