Dissimilar Resistance Spot Welding of DP 600/A5052/DP 600 Triple Sheets
Triple sheets of DP 600/A5052 aluminum alloy/DP 600 steel were joined by means of resistance spot welding in this study. The experimental results showed that the microstructure of fusion zone was lath martensite for DP 600 and column crystals for A5052. Their grains coarsened with increasing distance away from the base metals. The interface zone between DP 600 and A5052 was composed of continuous Fe2Al5 intermetallic compound (IMC) layer and needle-like Fe4Al13 IMC. When welding time prolonged from 8 cycles to 17 cycles, the average length of Fe4Al13 phase adjacent to A5052 shortened from 2.3 μm to 0.89 μm, whereas the thickness of Fe2Al5 IMC layer near DP 600 widened from 1.59 μm to 2.59 μm. The tensile-shear load of DP 600/A5052/DP 600 joints reached a maximum value of 10.796 kN with 14 cycles welding time. Failure during tensile-shear testing occurred along DP 600/A5052 interfaces because Fe2Al5 and Fe4Al13 were brittle phases, but an amount of tearing area was found on the fracture surface.
Publisher URL: https://link.springer.com/article/10.1007/s12541-018-0194-9