Mg-Zn-Sn-Er合金时效析出机制的研究

Aging Precipitation Mechanism of Mg-Zn-Sn-Er Alloy

改善镁合金的抗高温性能,增强镁合金的热稳定性一直是镁合金研究中的一个重要领域。本文研究了Mg-5Zn-3Sn-xEr(x=0、0.5、1、2)合金通过335℃保温24h,440℃保温24h,480℃保温18h的三级固溶后150℃中时效的析出机制。发现Mg-Zn-Sn-Er合金中铸态下凝固的相全部固溶于基体中。时效后,MgZn2的沉淀相以'β1平行于α-Mg基体的[0001]方向析出和'β2在(0001)生成。Mg_(2) Sn一般垂直于较长MgZn2针,呈现短条状,易于在MgZn2针的端部生长。MgSnEr以MgZn2作为形核质点进行异质形核。

Improving the high-temperature resistance and enhancing the thermal stability of magnesium alloys has always been an important field in the researc h of magnesium alloys.This article investigated the precipitation mechanism of Mg-5Zn-3Sn-xEr(x=0,0.5,1,2)alloy after threestage solid solution at 335℃for 24 hours,440℃for 24 hours,and 480℃for 18 hours,aged at 150℃.It was found that all the solidified phases in the Mg-5Zn-3Sn-xEr alloy were solutioned in the matrix.After aging,the precipitation phase of MgZn2 is parallel to the[0001]direction of Mg matrix and generation in(0001).Mg_(2) Sn is generally perpendicular to the longer MgZn2 needle and appears as a short strip,making it easy to grow at the end of the MgZn2 needle.MgSnEr undergoes heterogeneous nucleation using MgZn2 as the nucleation particle.