Research on laser weld bonding of duel phase steel to aluminium alloy

Laser weld bonding of DP590 dual phase steel to 6,016 aluminium alloy is studied in steel-on-aluminium overlap configuration. Microstructure, hardness distribution and mechanical properties of the welding joint are analysed. Results reveal that some defects, such as pores, cracks and softening in heat affected zone (HAZ), can be avoided in welding joints, and welding penetration depth and width increase compared with those of laser welding. The thermal conduction rate mounts up and the cooling rate of the welding joint ascends, laser energy is more absorbed by the lower aluminium alloy, which leads to Al element diffusion suppressed from the lower to the upper, and the Al content increasing in both sides of the weld in the molten state. The transverse area has increased in jointing steel to aluminium, and the shear load are shared by the adhesive and the weld, hence the mechanical properties of welding joint are significantly improved. [Received 4 November 2015; Revised 14 June 2016; Accepted 18 June 2016]