Critical assessment 27: dissimilar resistance spot welding of aluminium/steel: challenges and opportunities

Figures & data

Figure 1. Al-rich part of the Fe–Al phase diagram. Modified from Li et al. [31]. The approximate peak temperature at solid/liquid interface (T_S/L) during RSW is highlighted.

Figure 2. Schematic of macrostructure dissimilar resistance spot welds between aluminium and steel along with details of interfacial reaction zone. The bonding zone length, IMC thickness and indentation in Al sheet are determining factors for weld mechanical performance. When reaction layer (lower right part [40]) is thicker than a critical value, the joint fails via crack propagation through brittle IMC. Controlling the thickness of Al₅Fe₂ phase (left part [41]), the dominant phase in the IMC layer, is of crucial importance for producing strong and reliable dissimilar Al/steel welds.

Li X, Scherf A, Heilmaier M, et al. The Al-rich part of the Fe-Al phase diagram. J Phase Equilib Diff. 2016;37:162–173. doi: 10.1007/s11669-015-0446-7

 Web of Science ®Google Scholar

Chen N, Wang HP, Carlson BE, et al. Fracture mechanisms of Al/steel resistance spot welds in lap shear test. J Mater Process Technol. 2017;243:347–354. doi: 10.1016/j.jmatprotec.2016.12.015

 Web of Science ®Google Scholar

Qiu R, Iwamoto C, Satonaka S. Interfacial microstructure and strength of steel/aluminum alloy joints welded by resistance spot welding with cover plate. J Mater Process Technol. 2009;209:4186–4193. doi: 10.1016/j.jmatprotec.2008.11.003

 Web of Science ®Google Scholar