热变形温度和淬火速率对7085铝合金组织和性能的影响

采用力学性能测试、光学显微镜、扫描电镜和透射电镜,研究热变形温度和淬火速率对7085铝合金组织和力学性能的影响。结果表明:随着热变形温度降低,再结晶体积分数显著增加,合金的力学性能先提高后降低;随着淬火速率的降低,晶界析出相粗化,晶界无沉淀析出带宽化,合金的力学性能降低。合金热变形温度越低,其淬火敏感性越高,这是由于在缓慢冷却的过程中,再结晶引起的大角度晶界和非共格的Al3Zr粒子成为MgZn2相的有利形核位置,降低合金的时效强化效应。

Effect of hot deformation temperature and quench rate on microstructure and property of 7085 aluminum alloy

The influences of hot deformation temperature and quench rate on microstructure and property of 7085 aluminum alloy were investigated by tensile testing,optical microscopy(OM),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results show decreasing hot deformation temperature can greatly increase the volume fraction of recrystallization,and the mechanical properties firstly increase and then decrease.With the decrease of quenching rate,the size of precipitations coarsens and the width of precipitation free zone widens as well as the mechanical properties decrease.In addition,the lower the deformation temperatures are,the higher the quench sensitivity is,which is attributed to the large volume fraction of recrystallization resulting in a large amount of high angle grain boundaries and incoherent Al3Zr serve as the nucleation sites of η(MgZn2).As a result,the aging-hardening decreases.