固溶温度对Mg-10Gd-3Y-1.2Zn-0.5Zr合金的组织演变规律和时效硬化行为的影响

Effects of solution temperature on microstructure evolution and aging hardness of Mg-10Gd-3Y-1.2Zn-0.5Zr alloy

摘要:

利用OM、XRD、SEM和TEM研究了Mg-10Gd-3Y-1.2Zn-0.5Zr（wt.%）铸态合金的显微组织和不同温度下固溶热处理后的组织演变规律。结果表明Zn含量为1.2%的合金在等温固溶条件下，随时间的延长，晶界处LPSO层状生长，同时层状相向晶内延伸，层状相的层片变粗。随温度的升高铸态组织中原有的层状相溶解，而沿晶界化合物则向晶内有更宽的层状相生成，并随着温度的提高而变宽。此合金经不同温度的固溶后达到时效硬度最高可达115HV。

Abstract:

The microstructures of Mg-10Gd-3Y-1.2Zn-0.5Zr alloys after solution heat treatment at different temperatures comparing with the as-cast conditions were studied by using the optical microscope, XRD, SEM and TEM. The results showed that the LPSO lamellar phase grew with time increasing under the conditions of isothermal solution. At same time, the lamellar phase extending into grain which induced the lamellar to become widen. The original cast lamellar phase dissolution with the temperature increasing, however, a wider lamellar phase produced along compound located at the grain boundary. The new lamellar phase width increased with time. The alloy after solution treatment at 525℃ the sample hardness could reach 115 HV.