微量Mn对Mg-Li-Zn合金板材显微组织和力学性能的影响

Microstructure and properties of Mg-Li-Zn alloy sheets with Mn addition

向Mg-9%Li-2%Zn合金中添加适量的Mn,室温下将其轧制成板材。研究了微量元素Mn对合金板材显微组织和力学性能的影响。添加一定量的Mn(0.2%)可以使α相球化和细化,随着Mn含量的增加,α相变化不明显。室温下拉伸测试结果表明,添加一定量的Mn可以大大提高合金的强度和延伸率,随着Mn含量的增加,板材强度和延伸率有所下降,其中含0.5%Mn的合金强度最高,其抗拉强度和屈服强度分别提高了33.5%和25.8%。这是由于Mn在α相周围的富集使其细化和球化,进而提高合金强度;通过SEM和XRD分析可知,随着Mn含量的增加,大量颗粒状的化合物MgMn2O4和Li0.5MnO2生成,降低了合金的强度和延伸率。

Mg-9%Li-2%Zn （wt%）, alloys was produced and rolled to thin sheet at room temperature. Adding Mn from 0.2 %- 1.5 % to the alloy can refine grains. The effect is the best with Mn content being 0. 2 %--- 0. 5%. Mn addition can improve mechanical properties of the alloys at room temperature. Uniaxial tensile tests are carried out at room temperature. The tensile strengthen and yield strength of the alloys with 0. 5 % Mn addition may increase 33. 5% and 25. 8%, respectively. Both the strength and the elongation decrease with Mn content rising. It is clarified that adsorption of Mn on the grain boundary makes grains refined and improves the tensile properties of the sheets, but much hard particles of MgMn2 O4 and Li0.5 MnO2 worsen the properties.