Particle simulation of nugget formation process during steel/aluminum alloy dissimilar resistance spot welding and thickness estimation of intermetallic compounds

Abstract

A steel/aluminum alloy dissimilar resistance spot welding process was simulated by a three-dimensional smoothed particle hydrodynamics method. Furthermore, the time-dependent increase in the intermetallic compound thickness at the joint interface was estimated using the obtained numerical data of temperature history. As a result, the steel sheet started to melt from the center of the sheet in the thickness direction. The convection in the molten aluminum alloy caused by the electromagnetic force promoted the heat transfer at the solid-liquid interface because the temperature gradient becomes steeper. Moreover, the maximum thickness of the intermetallic compound was estimated to be approximately 1 µm. These results support the validity of the computational model developed in this study for simulating the nugget formation process during dissimilar resistance spot welding and estimating the intermetallic compound thickness.