RE(RE=Dy,Er)元素对Mg-Zn系合金微观结构及力学性能的影响

摘要

本文研究了铸态、固溶态和时效过程的Mg-1.67at.%Zn-2.3at.%Dy 与Mg-1.51at.%Zn-2.77at.%Er合金的微观结构变化及其力学性能的影响.微观分析结果表明,Mg-1.67at.%Zn-2.3at.%Dy 与 Mg-1.51at.%Zn-2.77at.%Er合金,在493 K温度下时效20 h硬度均达到峰值,峰值硬度分别为106.4 HV和98.7 HV.拉伸试验结果表明,固溶处理后,合金Mg-1.67at.%Zn-2.3at.%Dy 与Mg-1.51at.%Zn-2.77at.%Er的抗拉强度均有明显的提高.合金Mg-1.67at.%Zn-2.3at.%Dy固溶后包含三个相,分别是α-Mg相,Mg8ZnDy共晶相,Mg12ZnDy LPSO相(包括14H型和18R型).合金Mg-1.51at.%Zn-2.77at.%Er固溶后包含三个相,分别是α-Mg相,Mg3Zn3Er2共晶相, Mg12ZnEr LPSO相(包括14H型和18R型).%The microstructure and mechanical properties of the as-cast, solid solution and aging process of Mg-1.67at.%Zn-2.3at.% Dy and Mg-1.51at.%Zn-2.77at.%Er alloys have been studied. The experimental results indicated that aging-treatment at 493 K for 20 h the Mg-1.67at.%Zn-2.3at.%Dy and Mg-1.51at.%Zn-2.77at.%Er alloys could achieve their peak hardness 106.4 HV and 98.7 HV,respectively. The tensile test results showed that the tensile strength of the Mg-1.67at.%Zn-2.3at.%Dy and Mg-1.51at.%Zn-2.77at.% Er alloys were significantly improved after solution-treated. After solution-treated,Mg-1.67at.%Zn-2.3at.%Dy alloy contains three phases,i.e. α-Mg phase,Mg8ZnDy eutectic phase and Mg12ZnDy LPSO phase(including 14H-type and 18R-type). Similarly, the solution treated Mg-1.51at.%Zn-2.77at.%Er alloy contains three phases, i. e. α-Mg phase, Mg3Zn3Er2 eutectic phase and Mg12ZnEr LPSO phase(including 14H-type and 18R-type).