Mn对Mg-3.2Si合金组织和力学性能的影响

Effects of Mn on Microstructure and Mecahnical Properties of Mg-3.2Si Alloy

采用Mn对过共晶Mg-3.2Si合金进行变质处理,主要考察了Mn含量对合金中初生Mg2Si相的变质效果及合金力学性能的影响。结果表明,Mn对过共晶Mg-3.2Si合金中的初生Mg2Si相具有良好的变质效果。当Mn含量为2%(质量分数)时,变质效果最佳,此时初生Mg2Si相呈多边形,平均颗粒尺寸仅为32μm,相比未变质合金降低了56.8%。随着Mn含量的增加,合金的力学性能呈先提高后降低的趋势。当Mn含量为2%时,合金表现出最佳的力学性能,其抗拉强度和伸长率分别达到187 MPa和3.2%,相比未变质合金提高了67.0%和166.7%。

The hypereutectic Mg-3.2 Si alloy was modified by Mn.Effects of Mn addition on the modification of primary Mg2 Si and mechanical properties of Mg-3.2 Si alloy were investigated.Experimental results show that the primary Mg2 Si can be modified effectively.With 2% Mn addition,the morphology of primary Mg2 Si is changed from equiaxed dendritic to polyhedral.The average particle size of primary Mg2 Si reaches 32μm,decreased by 56.8%,compared with those of the unmodified alloy.The tensile strength and elongation of the modified alloys are increased with Mn addition increase.With 2% Mn addition,the tensile strength and elongation of the Mg-3.2 Si alloy reach 167 MPa and 3.2%,increased by49.1% and by 166.7%,respectively,compared with those of the unmodified alloy.