Laser assisted diffusion bonding of TC4 titanium alloy to 301 stainless steel using a Ni interlayer

Ni interlayer was applied in the lap welding of Ti6Al4V titanium (Ti) alloy and 301 stainless steel (SS). By adjusting the welding parameters, the SS irradiated by the laser was not completely penetrated. The SS/Ni and Ni/Ti interfaces were metallurgically bonded due to indirect heating. Two bonding interfaces formed based on solid phase diffusion bonding and eutectic reaction. As the laser power increased, the thickness of the remaining Ni interlayer gradually decreased. A Ni transition layer, as barrier to mixing of the two base materials can prevent the formation of Ti–Fe IMCs. The shear test results showed that the shear strength of the joint increased first and then decreased with the increase of laser power, and the maximum shear strength of joint was 269.8 MPa.