固溶处理对Mg-Gd-Y-Nd-Zr合金挤压板材组织与织构的影响

Abstract

本文采用金相显微观察、扫描电镜观察、能谱仪及织构测试等手段，研究了固溶处理对Mg-8Gd-4Y-Nd-Zr合金挤压板材组织与织构的影响，结果表明：随着固溶温度升高和固溶时间延长，合金的晶粒发生长大，同时挤压过程中形成的动态析出相逐渐溶入基体中；合金在500℃以下的温度固溶时，晶粒长大速度较慢，当温度高于500℃后，合金的晶粒长大速度明显增加，晶粒长大速度显著增加主要是由于合金中第二相粒子的快速溶解降低了其对晶界迁移的阻碍作用；随着固溶过程的进行，合金中基面织构的强度减弱而棱柱面织构的强度增强，棱柱面织构增强可归因于该类晶粒的择优生长。 Effects of solution treatments on microstructure and texture of an extruded Mg-8Gd-4Y-Nd-Zr alloy plate were investigated using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and texture testing. The results indicated that the grain growth occurred as the solution temperature increased and the solution time prolonged. The dynamic precipitates formed during extrusion dissolved into the matrix simultaneously as the solution processed. The grain growth rate was very low when the solution temperature was lower than 500˚C, while the grain growth rate increased rapidly when the sample solution treated at the temperature higher than 500˚C. The increase in grain growth rate was ascribed to the dissolution of dynamic precipitates, whose inhibiting effect on grain boundary migration decreased. The basal texture weakened while the prismatic texture strengthened as the solution processed. The strengthening in prismatic texture was attributed to the preferential growth of the prismatic texture component.