Mg-Y-Gd-Sm系铸造镁合金的显微组织和力学性能

Microstructure and Mechanical Properties of Mg-Y-Gd-Sm Series Casting Magnesium Alloy

针对生产中稀土镁合金低成本化,结合溶质总量控制与稀土耦合强化原理,设计了3种Mg-Y-Gd-Sm镁合金。结合DSC曲线和铸态组织分析3种合金离异共晶相占比;对比分析3种合金不同固溶处理后的组织及力学性能和不同温度的时效硬化曲线,以优化固溶及时效热处理工艺。结果表明,在砂型慢冷条件下Mg-4.5Y-2.5Gd-1.5Sm合金经530℃×24 h+200℃×100 h(T6)处理后,力学性能最优,抗拉强度、屈服强度、伸长率分别为267 MPa、200 MPa、2.0%。

Aiming at the low cost of rare-earth magnesium alloys under industrial production conditions,combining with the principle of total solute control and rare earth coupling strengthening,Mg-Y-Gd-Sm series casting magnesium alloys were designed.Combining with the DSC curve and the as-cast structure,the proportion of divorced eutectic phases in the alloys was analyzed.Meanwhile,the structure and mechanical properties of the alloys after solution treatment with different processes and the age hardening curves at different temperatures were analyzed comparatively to optimize the solution and age heat treatment process.The results show that the mechanical properties of the Mg-4.5 Y-2.5 Gd-1.5 Sm alloy prepared by the sand mold under the slow cooling condition are relatively desirable after the T6 heat treatment at 530℃×24 h+200℃×100 h,where the tensile strength,yield strength and elongation reach 267 MPa,200 MPa,2.0%,respectively.