热处理制度对7039铝合金抗腐蚀性能的影响

采用拉伸力学性能测试、金相显微观察、扫描电镜及透射电镜等分析手段,研究不同热处理制度下7039铝合金的力学性能及其在腐蚀液中浸泡后的腐蚀形貌.结合不同热处理制度后合金的腐蚀形貌与晶界析出相形貌,建立该系列合金晶界析出相形貌与腐蚀形貌的关系的示意模型.结果表明:在保持与T6处理的合金强度相当的基础上,经RRA处理可使抗腐蚀性能明显提高;在腐蚀液中浸泡腐蚀后,T6和RRA处理的合金表面呈成块状剥落腐蚀的现象,T73处理的合金呈点状腐蚀现象;T6处理后合金的纵向和横向最大腐蚀深度分别为378.53μm和31.91μm;T73处理的合金纵向和横向腐蚀深度分别为19.21 μm和8.07 μm:RRA处理的合金纵向和横向腐蚀深度分别为178.15 μm和15.38 μm.

Effect of heat treatment on corrosion resistance of 7039 aluminum alloy

The mechanical properties and microstructures after soak corrosion of 7039 aluminum alloy were investigated by means of tensile test, optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Combining with the microstructure of corrosion and grain boundary precipitate after different heat treatments, the model of relationship between precipitate microstructure and that of corrosion was established. The results show that the RRA treatment can remarkably increase the corrosion resistance while maintain tensile performance is as the same as that of T6 treatment. After eroded in the corrosion solution, the surface microstructures of the T6 treatment alloy and RRA treatment alloy show block exfoliation erosion and that of T73 treatment alloy shows pit corrosion. The greatest longitudinal and crosswise depth of corrosion are 378.53 μm and 31.91 μm after T6 treatment, 19.21 μm and 8.07 μm after T73 treatment, and 178.15 μm and 15.38 μm after RRA treatment, respectively.