Ca对变形Mg-9Li-2Zn合金显微组织和机械性能的影响

实验熔制了Mg-9%Li-2%Zn(质量分数)合金并研究了添加质量分数为0.1%~0.5%的Ca对合金的影响.合金板材具有良好的冷加工性能,室温下可以轧成2 mm厚的薄板.研究了微量元素Ca对板材显微组织和机械性能的影响.室温下对板材进行拉伸测试,结果表明添加元素Ca能够提高合金的机械性能,当添加质量分数为0.1%的Ca时,板材的抗拉强度和延伸率分别提高了19%和6%,随着Ca含量的增加,强度略有提高而延伸率下降.通过显微观察可知,Ca对显微组织有细化作用,其中含Ca 0.1%时效果最明显.通过分析结果可知Ca在晶界处的吸附致使显微组织细化,进而影响了板材的机械性能.

Effect of Ca on Microstructure and Mechanical Properties of Mg-Li-Zn Alloy

Mg-9wt % Li-2wt% Zn alloy was prepared with 0.1 -0.5 wt% Ca as alloying addition and cast in laboratory to investigate its effect on the alloy. The alloy plates have excellent mid-workability and can be rolled to 2mm-thin sheets at room temperature. Effect of Ca on the microstrueture and mechanical properties of the sheets was investigated. Uniaxial tension test was carried out at room temperature and the results showed that adding Ca can improve the mechanical properties. The tensile strength and elongation of the sheets are increased by 19% and 6%, respectively, when Ca content is 0. 1wt%, while the tensile strength increases slightly and elongation decreases with further increasing Ca content. In addition, Ca can offer grain refinement to the microstructure especially when Ca content is 0.1 wt%. The reason of grain refinement is the absorption of Ca at grain boundary, which further improves the mechanical properties of the sheets.