Microstructure and mechanical properties of friction-stir-welded high-Mg-alloyed Al-Mg alloy plates at different rotating rates  

作　　者：Ying-Li Li Wei-Jun Xia Hong-Ge Yan Ji-Hua Chen Tian Ding You-Ping Sun Xin-Yu Li 

机构地区：[1]School of Materials Science and Engineering,Hunan University,Changsha,410082,China [2]Hunan Provincial Key Laboratory of Spray Deposition Technology and Application,Hunan University,Changsha,410082,China [3]School of Mechanical and Transportation Engineering,Guangxi University of Science and Technology,Liuzhou,545006,China

出　　处：《Rare Metals》2021年第8期2167-2178,共12页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(No.51871093)。

摘　　要：Hot-rolled high-Mg-alloyed Al-Mg alloy(Al-9.2 Mg-0.8 Mn-0.2 Zr-0.15 Ti,labeled as 5 A12)plates were successfully friction stir welded at rotating rates ranging from 750 to 1500 r·min^(-1) at a constant welding speed of50 mm·min^(-1).The joints were characterized by optical microscopy(OM),electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),scanning electron microscopy(SEM),electron-dispersive spectroscopy(EDS),and tensile testing.All the joints are volume defectfree and exhibit fine,equiaxed dynamic recrystallization(DRX)grains with high-angle grain boundaries(HAGBs)fractions of 88.6%-93.3%in the nugget zones(NZs).The DRX grain size and the second-phase particle size in the NZs have a parabolic relation with the rotating rate.Furthermore,among the joints tested,the joint prepared at1000 r·min^(-1),which has the highest ultimate tensile strength((478±3)MPa)and the largest elongation to rupture(22.5%±1.4%)—approximately 87.5%and145.2%those of the base metal,respectively,exhibits the smallest grain size of 2.93μm,as well as the smallest particle size in the NZs.These excellent mechanical properties can be ascribed to the combined effects of the fine DRX grains with high fraction of HAGBs and the fine second-phase particles with a uniform distribution.

关 键 词：Al-Mg alloy Friction stir welding Dynamic recrystallization High ductility 

分 类 号：TG453.9[金属学及工艺—焊接] TG146.22[一般工业技术—材料科学与工程]