设计了一种成分为Al-0.42Mg-0.50Si-0.99Cu的新型工业型材用铝合金, 通过光学显微镜、透射电镜及万能拉伸试验机等研究了不同时效制度对其组织、力学性能以及晶间腐蚀性能的影响。结果表明: 合金在T6欠时效时晶界无明显析出相; T6峰时效时晶界析出物细小连续分布, 晶间腐蚀严重; 随时效时间延长, Q′相增多并逐渐粗化, 晶界析出物粗大呈非连续分布; 双级时效时晶内析出了大量Q′相, 晶界析出相球化且析出相之间的间距增大, 呈断续分布, 无析出带(PFZ)变宽, 抗腐蚀能力增强; 合金在T6峰时效时强度最高, 但晶间腐蚀敏感性大; 双级时效可在强度损失不大的情况下明显提高其耐蚀性。

A new type of Al-Mg-Si-Cu aluminum alloy was designed, and the alloy composition was Al-0.42Mg-0.50Si-0.99Cu. The effects of different aging treatments on microstructure, mechanical properties and corrosion behavior were studied by optical microscopy, transmission electron microscopy and means of conventional tensile test. The results show that no distinct grain boundary precipitates were observed in T6 under-aging state and the grain boundary precipitates are small and continuously distributed in T6 peak-aging state, and intergranular corrosion was serious. With the increase of aging time, Q′ phase increased and coarsened, the grain boundary precipitates were coarsened obviously and sparsely distributed. In double aging state, there are plenty of Q′ precipitates in matrix, grain boundaries precipitates were spheroidization, the spacing between precipitated phases increased, precipitated phaseand were continuously distributed and the PFZ was broaden. In T6 peak-aging state, the alloy had the most serious intergranular corrosion tendency and had the highest strength, however, the corrosion resistance was obviously improved while tensile strength was a little decrease in double aging state.