Mg-3Y-3Gd(-0.5Zn)铸造镁合金的显微组织和力学性能

Microstructure and Mechanical Properties of Mg-3Y-3Gd(-0.5Zn) Cast Magnesium Alloy

基于合金低成本化及“固溶强化增塑”的合金设计理念,以及航空航天大型复杂构件的砂型铸造条件,设计并对比研究了Mg-3Y-3Gd和Mg-3Y-3Gd-0.5Zn合金的微观组织及力学性能的演变。结果表明,两种合金铸态组织晶粒细小,无大块离异共晶相存在;Zn的加入引入了LPSO相,从而提升了强韧性。两种合金时效强化能力较弱,但Mg-3Y-3Gd-0.5Zn合金经500℃×24 h+200℃×50 h的T6处理后,其抗拉强度、屈服强度达到224 MPa、126 MPa,伸长率为21.2%,在要求高塑性的镁合金构件中有良好的应用潜力。

Based on the concept of “cost reduction” and “solid solution strengthening and ductilizing”,considering the slow cooling of sand mold casting conditions for large complex aerospace components,two kinds of Mg-3 Y-3 Gd-0.5 Zn alloys were designed to investigate the microstructure and mechanical properties.The results reveal that the as-cast microstructure of alloys has fine grain size,and absence of bulk divorced eutectic phase can be observed.The addition of Zn can introduce LPSO phase which improves the mechanical properties of alloy.The alloys have weak aging strengthening abilities.After heat treated by 500 ℃×24 h+200 ℃×50 h,the elongation,tensile strength and yield strenghth of Mg-3 Y-3 Gd-0.5 Zn alloy reach up to 21.2%,224 MPa and 126 MPa,respectively,presenting high application potential in magnesium production requiring high plasticity.