Improved mechanical properties of cast Mg alloy welds via texture weakening by differential rotation refill friction stir spot welding

SCRIPTA MATERIALIA

卷:203

Article

Fu, Banglong¹  Shen, Junjun¹  Suhuddin, Uceu F. H. R.¹  Chen, Ting¹  dos Santos, Jorge F.¹  Klusemann, Benjamin^1,2  Rethmeier, Michael^3,4 

[1] Helmholtz Zentrum Hereon, Inst Mat Mech Solid State Mat Proc, Max Planck Str 1, D-21502 Geesthacht, Germany

[2] Leuphana Univ Luneburg, Inst Prod & Proc Innovat, Univ Allee 1, D-21335 Luneburg, Germany

[3] Tech Univ Berlin, Inst Machine Tools & Factory Management IWF, Pascalstr 8-9, D-10587 Berlin, Germany

[4] BAM Bundesanstalt Materialforsch & Prufung, Unter Eichen 87, D-12205 Berlin, Germany

关键词: Refill friction stir spot welding;    Magnesium alloy;    Texture;    EBSD;    Plastic deformation;   

DOI  :  10.1016/j.scriptamat.2021.114113

来源: Elsevier

【 摘 要 】

Cast magnesium alloys welds produced by refill friction stir spot welding (refill FSSW) show low lap shear strength (LSS) and constantly fail in stirred zone (SZ) shear mode. The cause is most probably related to the heavily textured microstructure. Here, to re-engineer the resulting microstructure, we propose a novel process variant, the differential rotation refill FSSW (DR-refill FSSW). DR-refill FSSW stimulates discontinuous dynamic recrystallization and produces a bimodal microstructure with weakened texture. Therefore, the deformation incompatibility between SZ and thermal-mechanically affected zone is avoided. The welds have 50% higher LSS than that of standard refill FSSW welds, and fail in a different failure mode, i.e., SZ pull-out mode. DR-refill FSSW provides a new and effective strategy for improving the performance of spot welds based on microstructural engineering. (c) 2021 The Author(s). Published by Elsevier Ltd on behalf of Acta Materialia Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

【 授权许可】

Free