Microstructure and Mechanical Study on Laser-Arc-Welded Al–Zn–Mg Alloy

Abstract

Al–Zn–Mg alloy is widely used as lightweight material. Laser-arc hybrid welding is considered to be a suitable joining process for aluminum alloy. In this paper, 3-mm-thick 7075 aluminum alloy was welded by laser-arc hybrid welding method. The microstructure of the welded joint was analyzed. Microhardness measurement and tensile test were conducted. The fatigue test of the welded joint and base metal was carried out. And the feature of fatigue crack initiation and propagation were discussed.

Fig. 6 S–N curve of the welded joint.