Effect of Shot Peening on Properties of 7050 Aluminum Alloy FSW Joint
JIN Yuhua1,2,*, XING Yichu1, ZHOU Zizheng1, WU Bo1
1 School of Material Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China 2 State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China
Abstract: The 5 mm thick 7050 aluminum alloy friction stir welded joint was modified by shot peening modification. The residual stress measurement and low-cycle fatigue crack propagation test were carried out for the joints before and after shot peening. The effect of shot peening modification on the residual stress distribution of welded joints and the spread rate of fatigue cracks of nugget zone and heat affected zone were studied. The results show that shot peening treatment reduced the surface quality of the joints, but the surface layer and the near surface layer of the joint produce a hardened layer, and the hardness value of the surface layer after the secondary shot peening treatment reaches 198HV. The maximum hardness value of secondary shot peening is 33.1% higher than that of welding state. The residual compressive stress introduced by shot peening increases with the accumulation of the shot peening times, and the maximum pressure stress position moves deeper into the plate. The propagation rate of fatigue cracks of nugget zone and heat affected zone is reduced relative to the welded joint, which indicates the fatigue fracture resis-tance of the joint from the nugget zone and heat affected zone enhanced through the shot peening process.
1 Su R, Wang P P, Liu X R, et al. Chinese Journal of Rare Metals, 2019, 43(10), 1016(in Chinese). 苏孺, 王朋朋, 刘晓瑞, 等. 稀有金属, 2019, 43(10), 1016. 2 Deng C Y, Gao R, Gong B M, et al. Transactions of the China Welding Institution, 2018, 39 (11), 114(in Chinese). 邓彩艳, 高仁, 龚宝明, 等. 焊接学报, 2018, 39(11), 114. 3 Xie R J, Qiu X M, Chen F R, et al. Transactions of the China Welding Institution, 2014, 35(12), 35(in Chinese). 解瑞军, 邱小明, 陈芙蓉, 等. 焊接学报, 2014, 35(12), 35. 4 Hitoshi S. Journal of Materials Processing Technology, 2017, 1(1), 3. 5 Zhang J H, Cheng X Q, Xia Q X, et al. Advances in Mechanical Engineering, 2020, 12(8), 1. 6 Jin Y H, Wu Y W, Wang X J, et al. Transactions of the China Welding Institution, 2019, 40 (4), 50(in Chinese). 金玉花, 吴永武, 王希靖, 等. 焊接学报, 2019, 40(4), 50. 7 Terumasa K, Sano T, Hirose A, et al. Journal of Materials Processing Technology, 2018, 262, 111. 8 Wu J F, Zou S K, Gong S L, et al. Rare Metal Materials and Enginee-ring, 2020, 49 (10), 3395(in Chinese). 吴俊峰, 邹世坤, 巩水利, 等. 稀有金属材料与工程, 2020, 49(10), 3395. 9 Xiao X D, Xin T, Liu Y W, et al. International Journal of Mechanical Sciences, 2018, 137, 182. 10 Soyama H, Simoncini M, Cabibbo M. Metals, 2020, 11(1), 59.