Microstructure and mechanical properties of wire-filled tungsten argon arc welded joints for LA141 magnesium-lithium-aluminum alloy

Wire-filled tungsten argon arc welding was carried out on LA141 alloy plates with specially prepared homogenous welding wires in an argon gas protection device. The microstructure and mechanical properties of joints were described and analyzed. The results show that the apparent quality and formability of welding seams are excellent, the lithium burning loss of joints is controlled effectively. The composition and microstructure of joints are relatively uniform which can be divided into base metal zone, heat-affected zone, transition zone and fusion zone, the transition zone plays a key role in the joint performance which be reflected in the smooth transition distribution of joints hardness and the improvement of the consistency for joints structure and performance. After post-weld heat treatment, the comprehensive properties of welded plates are further improved with a tensile strength of 124 MPa and an elongation of 16 %, the hardness distribution becomes more even.