Influencing mechanism of pre-existing nanoscale Al5Fe2 phase on Mg-Fe interface in friction stir spot welded Al-free ZK60-Q235 joint  

作　　者：R.Z.Xu Q.Yang D.R.Ni B.L.Xiao C.Z.Liu Z.Y.Ma 

机构地区：[1]Institute of Metal Research,Chinese Academy of Sciences,Shenyang,110016,China [2]College of Material Science and Engineering,Shenyang Aerospace University,Shenyang,110136,China [3]Department of Materials Science and Engineering,University of Illinois at Urbana-Champaign,1304 W Green St,Urbana,IL,61801,United States [4]Fredrick Seitz Materials Research Laboratory,University of Illinois at Urbana-Champaign,104 S Goodwin Ave,Urbana,IL,61801,United States

出　　处：《Journal of Materials Science & Technology》2020年第7期220-228,共9页材料科学技术（英文版）

基　　金：This work was supported financially by the National Natural Science Foundation of China(Nos.51601121,51371179 and 51331008);Electron microscopy experiments were carried out at the Center for Microanalysis of Materials at the Frederick Seitz Materials Research Laboratory of University of Illinois at Urbana-Champaign,and supported by Department of Energy Basic Energy Sciences(No.DEFG02-01ER45923)。

摘　　要：Al-free ZK60 magnesium (Mg) alloy sheet was selected as substrate material of Mg-steel pinless friction stir spot welding (FSSW), avoiding the effect of the Al element in the substrate on the alloying reaction of Mg-iron (Fe) interface. The sound FSSW joint of ZK60 Mg alloy and Q235 steel with a hot-dipped aluminum (Al)-containing zinc (Zn) coating was successfully realized. The detailed microstructural examinations proved that Al5Fe2 phase at the Mg-Fe interface came from the pre-existing Al5Fe2 phase in the coating and acted as the transition layer for promoting the metallurgical bonding of Mg and Fe. The interfaces with well-matched lattice sites among Fe, Al5Fe2 and Mg were formed during FSSW. A low energy interface with good match of lattice sites ((002)Al5Fe2//(110)Fe, [110]Al5Fe2//[113]Fe) between Al5Fe2 and Fe was identified. For the interface between Al5Fe2 and Mg, an orientation relationship of (622)Al5Fe2//(3112)Mgand[158]Al5Fe2//[2423]Mg was observed. The tensile-shear load of the ZK60-steel joint could reach 4.6 kN. Moreover, the joint fracture occurred at the interface between the Al5Fe2 layer and the Mg alloy substrate, suggesting the brittle fracture characteristic.

关 键 词：Dissimilar welding Friction stir spot welding Magnesium alloys STEELS Zinc coating 

分 类 号：TG453.9[金属学及工艺—焊接]