【摘要】 采用金相显微镜、扫描电镜和硬度测试等手段,研究了固溶和时效热处理对Mg-Nd-Zr合金组织和性能的影响。结果表明,合金经460~520℃固溶处理后,随着固溶温度的升高和保温时间的延长,铸态组织中晶界上的化合物逐渐溶解,当固溶温度过高和保温时间过长时,晶粒长大。合金经490℃×8h固溶处理后时效,随着时效时间的延长,固溶时残留的第二相逐渐溶解,均匀析出第二相,合金硬度逐渐增大,达到峰值后进入过时效阶段,析出的第二相变大,硬度值下降。Mg-Nd-Zr合金的最佳热处理工艺为经490℃×8h固溶处理后,进行225℃×4h时效。更多还原

【Abstract】 Effect of solid solution and aging heat treatment on microstructure and mechanical properties of Mg-Nd-Zr alloy were investigated by optical microscope,scanning electron microscopy and hardness tester.The results show that with the increase of solution temperature and holding time,compounds in the grain boundaries are dissolved gradually when the alloy is treated at 460℃to 520℃.When the solution temperature is too high and the holding time is too long,grain is grown up.With the increase of aging time,the solution residual phase is dissolved gradually,and the second phase is precipitated homogeneously,so the alloy hardness is increasesd after solid solution at 490℃for 8h.The second phase is coarsened as a result of over-aging,which leads to the decrease of hardness.After 490℃×8hsolid solution treatment and 225 ℃ ×4haging treatment,the Mg-Nd-Zr alloy has the desirable mechanical properties.更多还原