Understanding formation mechanisms of intermetallic compounds in dissimilar Al/steel joint processed by resistance spot welding

Bo Pan, Hui Sun, Shun Li Shang, Mihaela Banu, Pei Chung Wang, Blair E. Carlson, Zi Kui Liu, Jingjing Li

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

This paper confirmed the formation mechanism of intermetallic compounds (IMCs) in Al/steel resistance spot welds with transmission electron microscopy, electron backscatter diffraction, nanoindentation and thermodynamic calculations. In particular, the formation of AlFe with BCC_B2 structure, which is not commonly seen in welds, was identified. The formation mechanism of IMCs at the high welding energy region is described as follows. Al13Fe4 first nucleates from the Al side, followed by Al5Fe2 growth with Fe atoms accumulating at the Al13Fe4 grain boundaries. Then, Al5Fe2 grains grow continuously to coarse columnar grains, and AlFe forms at the interface of Al5Fe2 grains and the ferrite phase. Lastly, the needle-like Al13Fe4 forms in the cooling process. At the middle welding energy region, only equiaxed Al5Fe2 and small Al13Fe4 grains are formed at the interface because of the lower diffusion rates of Al and Fe, hence postponing the growth of Al5Fe2 and Al13Fe4. At the low welding energy region, only sporadic Al5Fe2 and Al13Fe4 grains are formed surrounded by the Al phase.

Original languageEnglish (US)
Pages (from-to)212-222
Number of pages11
JournalJournal of Manufacturing Processes
Volume83
DOIs
StatePublished - Nov 2022

All Science Journal Classification (ASJC) codes

  • Strategy and Management
  • Management Science and Operations Research
  • Industrial and Manufacturing Engineering

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