Mechanical and corrosion fatigue behaviors of gradient structured 7B50-T7751 aluminum alloy processed via ultrasonic surface rolling  

作　　者：Xingchen Xu Daoxin Liu Xiaohua Zhang Chengsong Liu Dan Liu 

机构地区：[1]Corrosion and Protection Research Laboratory,Northwestern Polytechnical University,Xi’an 710072,China

出　　处：《Journal of Materials Science & Technology》2020年第5期88-98,共11页材料科学技术（英文版）

基　　金：supported financially by the National Natural Science Foundation of China(No.51771155);the Equipment Pre-research Field Foundation(No.61409220202).

摘　　要：In this work,ultrasonic surface rolling process(USRP)was utilized to produce a gradient structured layer on 7 B50-T7751 aluminum alloy,and the mechanical properties and corrosion fatigue behavior of treated samples were studied.These results reveal that underwent USRP,a 425~m thick gradient structure and a 700~m deep compressive residual stress field are created,aluminum grain size become fine(~67 nm),and the corrosion rate of treated surface reduces by 60.08%owing to the combined effect of compressive residual stress and surface nanocrystallization.The corrosion fatigue strength is enhanced to 117%of that of 7 B50 Al alloys by means of USRP due to the introduced compressive residual stress,which is considered as the major favorable factor in suppressing the initiation and early propagation of corrosion fatigue cracks.Besides,the gradient structure is an important factor in providing a significant synergistic contribution to the improvement of corrosion fatigue performance.In this work, ultrasonic surface rolling process(USRP) was utilized to produce a gradient structured layer on 7 B50-T7751 aluminum alloy, and the mechanical properties and corrosion fatigue behavior of treated samples were studied. These results reveal that underwent USRP, a 425 ~m thick gradient structure and a 700 ~m deep compressive residual stress field are created, aluminum grain size become fine(~ 67 nm),and the corrosion rate of treated surface reduces by 60.08% owing to the combined effect of compressive residual stress and surface nanocrystallization. The corrosion fatigue strength is enhanced to 117% of that of 7 B50 Al alloys by means of USRP due to the introduced compressive residual stress, which is considered as the major favorable factor in suppressing the initiation and early propagation of corrosion fatigue cracks. Besides, the gradient structure is an important factor in providing a significant synergistic contribution to the improvement of corrosion fatigue performance.

关 键 词：Aluminum alloy MECHANICAL properties CORROSION fatigue behavior Gradient structure COMPRESSIVE residual stress ULTRASONIC surface ROLLING process 

分 类 号：TG339[金属学及工艺—金属压力加工]