Analysis of local microstructure and strengthening mechanisms in adjustable-gap bobbin tool friction stir welds of Al-Mg  

作　　者：Dong Wu Wenya Li Qiang Chu Yangfan Zou Xichang Liu Yanjun Gao 

机构地区：[1]State Key Laboratory of Solidification Processing,Shaanxi Key Laboratory of Friction Welding Technologies,Northwestern Polytechnical University,Xi’an 710072,China [2]Capital Aerospace Machinery Company,Beijing 100076,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2022年第8期1589-1595,共7页矿物冶金与材料学报（英文版）

基　　金：This work was financially supported by the State Key Laboratory of Solidification Processing(Northwestern Polytechnical University,China,No.2019-QZ-01);the National Natural Science Foundation of China(No.52105402);the Natural Science Foundation of Shaanxi Province(No.2021-JQ-102).

摘　　要：The bobbin tool friction stir welding process was used to join 6 mm thick 5A06 aluminum alloy plates.Optical microscope was used to characterize the microstructure.The electron backscatter diffraction(EBSD)identified the effect of non-homogeneous microstructure on the tensile properties.It was observed that the grain size in the top of the stir zone(SZ)is smaller than that in the centre region.The lowest ratio of recrystallization and density of the geometrically-necessary dislocations(GNDs)in the SZ was found in the middle near the thermo-mechanically affected zone(TMAZ)being 22%and 1.15×10^(−13) m^(−2),respectively.The texture strength of the heat-affected zone(HAZ)is the largest,followed by that in the SZ,with the lowest being in the TMAZ.There were additional interfaces developed which contributed to the strengthening mechanism,and their effect on tensile strength was analysed.The tensile tests identified the weakest part in the joint at the interfaces,and the specific reduction value is about 93 MPa.

关 键 词：friction stir welding bobbin-tool local microstructure strengthening mechanisms adjustable-gap 

分 类 号：TG453.9[金属学及工艺—焊接]