新型Mg-Li-Mn合金的显微组织和力学性能

Microstructure and Mechanical Properties of Mg-Li-Mn Alloy

向Mg-9Li合金中添加0.5%～2%(ω)Mn,并在室温下对合金板材进行拉伸测试.结果表明,Mn能够细化α-Mg相,铸态显微组织由α-Mg,β-Li相及富Mn新相组成,合金板材具有较高的强度和良好的延伸率;随着Mn含量的增加,强度不断提高,延伸率有所下降.通过金相观察、SEM和XRD分析可知,随着Mn含量的增加,其存在形式由固溶状态转变为以富Mn新相为主,对合金起到了强化作用,进而能够提高强度.

Mg-Li-Mn alloy is produced and rolled to thin sheet at room temperature in the present work. Adding Mn from 0.5% to 2% to the alloy can refine the crystalline grains. The resulting microstructure of alloy consists of α-Mg, β-Li and new Mn-rich phase. Uniaxial tension tests are carried out at room temperature. The prepared sheets have good tensile strengthen and yield strength. They can be raised by 16% and 17%, respectively, with Mn content increasing from 1% to 2%. It is observed that the existence of Mn on the grain boundary makes the grains refined, and hard particles of MgMn2O4 and Li0.5MnO2 forming in the alloy improves its mechanical properties.