Effect of heat treatment on microstructures and mechanical properties of Al-Li-Cu alloy TIG welded joint

The strength of Al-Li-Cu alloy TIG welded joint is lower,and only is 55% of parent material strength,resulting from being softened during welding.To solve the problem,this paper studied the effect of solution and ageing heat treatment on the micro structures and properties of Al-Li-Cu TIG welded joint.The results show that strength coefficient of the joint is increased to 0.64 after heat treatment at 520℃ for 1 h+150℃ for 10 h.However,the strength of parent material is reduced after heat treatment.Parent material strength is decreased to 31% of original strength after heat treatment at 520℃ for 1 h+176℃ for 10 h.As ageing temperature and time increasing,the damaged degree for parent material rises.