时效状态及Cu含量对Al-Cu合金晶间腐蚀敏感性的影响  

Effect of Aging State and Cu Content on Intergranular Corrosion Sensitivity of Al-Cu Alloy

作　　者：李海 周洋[1] 王芝秀 LI Hai;ZHOU Yang;WANG Zhixiu(School of Materials Science and Engineering,Changzhou University,Changzhou 213164,China;Jiangsu Key Laboratory of Materials Surface Science and Technology,Changzhou University,Changzhou 213164,China)

机构地区：[1]常州大学材料科学与工程学院,江苏常州213164 [2]常州大学江苏省材料表面科学与技术重点实验室,江苏常州213164

出　　处：《热加工工艺》2022年第10期122-126,共5页Hot Working Technology

基　　金：国家自然科学基金资助项目(51571038,51671038);江苏省自然科学基金面上项目(BK20171195);江苏省高等学校自然科学研究重大项目(18KJA430002)。

摘　　要：采用硬度、加速腐蚀、电化学测试以及扫描和透射电镜分析,研究Al-xCu合金(x=0.54、1.05、2.10、3.60、4.50,wt%)不同时效态的晶间腐蚀(IGC)敏感性。结果表明,随着时效时间延长,低Cu合金始终具有IGC敏感性,且腐蚀程度逐渐加重;高Cu合金首先发生IGC,并在过时效阶段转为稳态点蚀。微观组织及电化学分析表明,低Cu合金的IGC源于晶界富Cu层与无析出区(PFZs)形成腐蚀微电池,且腐蚀程度加重与富Cu层中偏聚程度增大有关;高Cu合金的IGC源于基体及晶界析出相与PFZs形成腐蚀微电池,但时效过程中晶界析出相由连续分布逐渐转变为断续分布,决定了合金腐蚀行为由IGC向稳态点蚀转变。此外,高Cu合金在过时效阶段发生的稳态点蚀还与含Cu结晶相及基体成分有关。The intergranular corrosion(IGC) sensitivity of Al-xCu alloys(x=0.54, 1.05, 2.10, 3.60, 4.50, wt%) with different effective states was investigated by hardness, accelerated corrosion, electrochemical measurements, scanning and transmission electron microscopy analysis. The results show that the low Cu alloy always has IGC sensitivity and the corrosion degree increases with the aging time increasing. The high Cu alloy first generates IGC, and is converted to steady-state pitting corrosion in the obsolete phase. Microstructure and electrochemical analysis show that the IGC of low Cu alloy originates from the formation of corrosion microbattery with grain boundary rich Cu layer and non-evolution zone(PFZs), and the increase of corrosion degree is related to the increase of segregation degree in rich Cu layer. The IGC of high Cu alloys is derived from the formation of corrosion microbatteries with the PFZs of matrix and grain boundary precipitates. However, the grain boundary precipitates gradually change from continuous distribution to intermittent distribution during aging, which determine the change of corrosion behavior from IGC to steady-state pitting. Moreover, the steady-state pitting corrosion of high Cu alloys during the out-of-date effect stage is also related to the Cu crystalline phase and matrix composition.

关 键 词：AL-CU合金 峰时效 过时效 晶间腐蚀 点蚀 

分 类 号：TG156.9[金属学及工艺—热处理] TG174.33[金属学及工艺—金属学]