7075-T6铝合金厚度截面组织和晶间腐蚀性能不均匀性的研究  

Study on Inhomogeneity of Microstructure and Intergranular Corrosion Properties on Thickness Section of 7075-T6 Aluminum Alloy

作　　者：徐效栋 王芝秀 顾晓彤[1] XU Xiaodong;WANG Zhixiu;GU Xiaotong(School of Materials Science and Engineering,Changzhou University,Changzhou 213164,China;Jiangsu Key Laboratory of Material 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》2025年第6期67-71,共5页Hot Working Technology

基　　金：国家自然科学基金项目(52171029)。

摘　　要：采用晶间腐蚀实验、光学显微镜、扫描电镜、透射电镜等方法,研究了7075-T6铝合金纵截面组织和耐晶间腐蚀性能的不均匀性。结果表明:合金表层与中心层的组织和耐晶间腐蚀性能存在明显差异。表层再结晶分数约为89%,再结晶晶粒长宽比约为6,时效析出相尺寸约为3 nm,再结晶晶粒腐蚀敏感性低,为均匀腐蚀特征;中心层再结晶分数约为50%,存在大量平均尺寸约为3μm的亚晶粒,再结晶晶粒长宽比约为11,时效析出相尺寸约为6 nm,再结晶晶粒腐蚀敏感性高,亚晶界由于是小角度晶界,间接切断了向亚晶界的腐蚀通道,使得腐蚀沿着再结晶晶粒扩展,表现为局部腐蚀特征。相比表层,中心层再结晶晶粒的长宽比和晶内时效析出相尺寸更大,导致其晶间腐蚀敏感性更高。The inhomogeneity of microstructure and intergranular corrosion resistance of longitudinal sections of 7075-T6 aluminum alloy were studied by intergranular corrosion test,optical microscope,scanning electron microscope and transmission electron microscope.The results show that there are obvious differences in microstructure and intergranular corrosion resistance between the surface layer and the central layer.The recrystallization fraction of the surface layer is about 89%,the length/width ratio of recrystallized grains is about 6,and the size of aging precipitates is about 3 nm.The corrosion sensitivity of recrystallized grains is low,and the corrosion characteristics are uniform.The recrystallization fraction of the central layer is about 50%,and there are a large number of subgrains with an average size of about 3μm.The length/width ratio of the recrystallized grains is about 11,and the size of the aging precipitates is about 6 nm.The recrystallization corrosion sensitivity is high.Because the subgrain boundary is a small-angle grain boundary,the corrosion channel to the subgrain boundary is indirectly cut off,so that the corrosion spreads along the recrystallized grain,showing local corrosion characteristics.Compared with those of the surface layer,the length-width ratio and intragranular aging precipitated phase size of recrystals in the central layer are larger,resulting in higher intergranular corrosion sensitivity.

关 键 词：7075铝合金 再结晶 亚晶 晶间腐蚀 

分 类 号：TG146.21[一般工业技术—材料科学与工程]