Mg-4%Al-0.8%Sb-xRE镁合金的显微组织和力学性能

Microstructure and Mechanical Properties of Mg-4%Al-0.8%Sb-xRE Magnesium Alloy

以锑元素取代Mg-4%Al-2%RE(AE42)镁合金中的部分稀土元素,制备了Mg-4%Al-0.8%Sb-xRE合金(x<2%),用SEM、XRD、万能拉伸试验机等分析了合金显微组织和力学性能随稀土元素含量x的变化。结果表明:铸态AE42镁合金的显微组织主要由-αMg基体、针状及少量的颗粒状Al11RE3相组成;加入0.8%的锑元素后,随着合金中稀土元素含量的减少,基体中针状Al11RE3相的数量逐渐变少且形态逐渐变短、变细,同时基体中出现了弥散分布的小颗粒状RE2Sb和大颗粒状RESb化合物相和少量的骨骼状-βMg17Al12相,且RESb相逐渐增多、变大;随着合金中稀土元素含量的增加,合金的力学性能逐渐提高,当稀土元素含量达到1.3%时,合金的力学性能基本达到AE42镁合金的水平。

A series of Mg-4%Al-0. 8%Sb-xRE magnesium alloys added 0. 8%Sb instead of some RE were prepared. Changes of the mechanical properties and microstructure of the alloys with RE content were investigated by SEM, XRD and universal tensile testing machine. The results indicate that the as-cast microstructure of AFA2 alloy was composed of a matrix, some needle-shaped and granular Al11 RE3 phase. With the decrease of RE content, the number of needle-shaped Al11 RE3 phase decreased, and its shape became thinner and shorter, a small quantity of β-Mg17 Al12 and dispersed RESb and RE2Sb particles appeared in the matrix at the same time, and the number of RESb particles increased while the shape of them became larger. The mechanical properties improved gradually with the increase of RE content, and achieved the level of AF42 alloy when the RE content was 1.3%.