The influence of joint geometry on the interfacial bonding in laser-brazed flare joints of automotive steels

Laser brazing of thin-gauge Zn-coated steel in a flare V-groove configuration is used in automotive industry, although the effect of joint geometry on interfacial bonding and weld deformation has not been previously published. This work reveals that the V-groove size affected the distribution of laser irradiation and the energy absorption by the joint. Focusing the laser on the top of joint with a smaller groove results in an unwetted gap, while more reflected laser energy by Cu filler promotes the interfacial bonding in a larger V-groove forming a fully wetted and uniform interface. This difference further affected the mechanical properties.