Sn对Mg-5Zn-2.5Al合金微观组织与性能的影响

利用光学显微镜、扫描电镜、万能试验机等分析测试设备研究了Sn对Mg-5Zn-2.5Al-xSn(x=0,1,2,3,4)(ZAT52x)合金组织结构及力学性能的影响.采用Thermo-Calc热力学软件计算了ZAT52x(x=0,2,4)3种合金在Scheil模型条件下液相质量分数与温度的关系以及凝固过程中的相变反应....

Effects of Sn on the microstructures and properties of Mg-5Zn-2.5Al alloy

In this study,the effects of different Sn contents on the microstructures and mechanical properties of Mg-5Zn-2.5Al-xSn(x=0, 1, 2, 3, 4) (ZAT52x) alloys were investigated. Curves of the mass fraction of liquid versus temperature during solidification of Mg-5Zn-2.5Al-xSn (x=0, 2, 4) (ZAT52x) were calculated using the Thermo-Calc software. It is found that α-Mg, Mg₂Sn (not precipitated when x=0), φ-Mg₂₁(Zn,Al)₁₇, τ-Mg₃₂(Zn,Al)₄₉, and MgZn precipitate in sequence during the solidification of ZAT52x magnesium alloy. As the Sn addition increases, the melting point of the ZAT52x alloy decreases and the amount of the second phases increases, and the tensile strength and elongation of the as-cast ZAT52x increased at first and then decreased. The as-cast ZAT522 alloy exhibits the best mechanical properties with tensile strength of 245.9 MPa and elongation of 14.4%. After extrusion, the ZAT522 alloy exhibits the highest tensile strength (376.2 MPa) and elongation (20.8%), while the ZAT524 alloy shows a more balanced mechanical property with tensile strength, yield strength, and elongation of 363.7 MPa, 260.4 MPa, and 17.9%, respectively.