Hot-cracking susceptibility and shear fracture behavior of dissimilar Ti6Al4V/AA6060 alloys in pulsed Nd:YAG laser welding

[Display omitted] •The hot-cracking formation of the dissimilar Ti6Al4V/AA6060 lap joint using pulsed Nd:YAG laser welding is highlighted.•The influence of the welding process parameters on HCS is experimentally investigated through single-factor analysis.•The shear fracture behavior of the dissimilar Ti/Al joint is analyzed through microstructural characterization.•The sources of hot crack formation are explored concerning the generation of inter-metallic compounds and residual stress in the weld. Laser welding of dissimilar titanium/aluminum alloys has been employed at an increasing rate, particularly in the aerospace industry, owing to its advantages in terms of current design flexibility and fuel/cost savings. The major problem with dissimilar Ti/Al welds arises from the difference in the thermal expansion and contraction of the two metals, which leads to hot-cracking susceptibility and the mitigation of the mechanical property after welding. In the present study, pulsed Nd:YAG laser welding of Ti6Al4V and AA6060 has been addressed. Hot-cracking susceptibility in the heat affected zone and the shear fracture behavior of the lap joints were investigated through microstructural characterization and mechanical tests. The results indicate that the hot cracking tendency can be reduced by increasing the pulse peak power (7.5–8.5 kW) and the laser point diameter (0.8–1.0 mm) with specific pulse duration and overlap. An alternative control strategy for less hot cracks in the Ti/Al lap joint can be to increase the weld width and decrease the cooling rate during solidification. The shear fracture of the Ti/Al lap joint is likely to occur along the lower side path of the weld interface with decreasing weld surface collapsed amount and increasing aluminum base metal melt depth.