Zn元素对Mg-25Sn合金组织和力学性能的影响

Effect of Zn on Microstructures and Mechanical Properties of Mg-25Sn Alloys

摘要:

以Mg 粉、Sn 粉和Zn 粉为初始原料,采用机械合金化和热压烧结的方法制备Mg-25Sn-xZn合金。研究了Zn添加量对Mg-25Sn合金显微组织和性能的影响。结果表明：Mg-25Sn-xZn体系的机械合金化过程中,Zn元素不参与合金化反应,但Zn的引入降低了Mg+Mg₂Sn混合物的尺寸。除固溶外,烧结态Mg-25Sn-xZn中Zn完全转变成MgZn₂相。且随Zn含量的增加,MgZn₂相的尺寸逐步增大,Mg晶界和Mg₂Sn颗粒相周围是MgZn₂相的择优分布位置。添加6wt% Zn的Mg-25Sn合金具有最优的力学性能,其显微维氏硬度1.60GPa、屈服强度388MPa、抗压强度497MPa、断裂应变7.5%。

Abstract:

Mg-25Sn-xZn alloys were prepared by mechanical alloying and hot-press sintering methods using Mg powders, Sn powders and Zn powders as raw materials. The effects of the Zn content on microstructures and mechanical properties of the Mg-25Sn alloys were studied. The results show that Zn didn"t participate with the alloying reaction in the mechanical alloy process of Mg-25Sn-xZn system, but the introduction of Zn reduced the size of Mg+Mg₂Sn mixture. The Zn in the sintered Mg-25Sn-xZn was completely transformed into MgZn₂ phase except the solution. And with the increase of the Zn content, the size of MgZn₂ phase gradually increased. MgZn₂ phase was preferentially distributed along Mg grain boundary and around Mg₂Sn particle phase. When the Zn addition is 6wt%, the Mg-25Sn alloy exhibited excellent mechanical properties, hardness, yield strength, fracture strength and strain are 1.60GPa, 388MPa, 497MPa and 7.5% respectively.