二次固溶温度对7075铝合金组织及耐腐蚀性影响

Effect of Second Solution Temperature on Microstructure and Corrosion Resistance of 7075 Al Alloy

采用不同二次固溶温度对挤压态7075铝合金进行强化,通过激光共聚焦金相组织观察及电化学腐蚀试验研究了不同二次强化处理条件下的显微组织形貌、第二相分布以及耐电化学腐蚀性能。试验结果表明:不同二次强化固溶处理条件下,激光共聚焦金相组织中不同程度弥散析出第二相组织,同时耐电化学腐蚀性能也有较大不同,其中一次固溶条件为420℃保温2 h,二次固溶480℃保温2 h,然后进行120℃保温10 h时效处理,基体中析出大量的第二相,并均匀弥散分布在基体晶界处,且经电化学腐蚀液进行腐蚀之后基体表面腐蚀点较少,具有较高的耐腐蚀性。

By using different methods of secondary solution for the extrusion state of 7075 aluminum alloy,microstructure morphology, the distribution of the second phase and chemical corrosion resistance of 7075 aluminum alloy under the conditions of different second solution were analysised and studied by the laser confocal microstructure observation and the electrochemical corrosion test. The results show that, the laser confocal microstructure in different degrees of dispersion, and at the same time, the second phase microstructure and electrochemical corrosion resistance also has great difference under the different conditions of secondary solution treatment. Among them, when taking 7075 aluminum alloy on the 420 ℃ for 2 h heating, and then heating at 480 ℃ for 2 h, after aging at 120 ℃ for 10 h, there are a large number of the second phase and microstructure dispersion evenly distributes in the matrix of the grain boundary, and after corrosion in the electrochemical corrosion liquid, there are less corrosion points on substrate surface, and it has higher corrosion resistance.