Fatigue crack propagation of 7050 aluminum alloy FSW joints after surface peening  

作　　者：金玉花 陈永昇 马悦铭 王希靖 郭廷彪 Jin Yuhua;Chen Yongsheng;Ma Yueming;Wang Xijing;Guo Tingbiao(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,School of Materials Scienceand Engineering,Lanzhou University of Technology,Lanzhou 730050,China;School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,School of Materials Scienceand Engineering,Lanzhou University of Technology,Lanzhou 730050,China [2]School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China

出　　处：《China Welding》2023年第1期18-26,共9页中国焊接（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grants 51865028);the Gansu Provincial Science and Technology Planning Project(Grant No.20YF8GA056).

摘　　要：The surface composite modification of the 7050 aluminum alloy friction stir-welded joints was performed by shot peening(SP)/multiple rotation rolling(MRR)and MRR/SP,and the fatigue performance of the nugget zone(NZ)was investigated.The results demonstrated that the fatigue life of SP/MRR samples is longer than that of MRR/SP.On the plane 150μm below the surface.The grains with high angle grain boundary account for 71.5%and 34.3%for MRR/SP and SP/MRR samples,respectively.The crack propagation path of the MRR/SP is transgranular and intergranular,and it is intergranular for the MRR/SP.Multitudinous fatigue striations and some voids appeared at the fracture during the stable crack propagation stage.However,fatigue striations for SP/MRR are with smaller spacing,fewer holes,and smaller size under SP/MRR compared with fatigue fracture of MRR/SP.The differences in fatigue properties and fracture characteristics of the NZ are related to the microstructure after the two combined surface modifications.

关 键 词：7050 aluminum alloy surface compound modification fatigue crack propagation weld nugget zone 

分 类 号：TG453.9[金属学及工艺—焊接]