Effect of trace Zr on microstructures and properties of welded joint of Al-5.8Cu-0.3Mn alloy

A-15.8Cu0.3Mn alloy was welded using 4047 solder wire with metal inert-gas welding Mechanical properties and microstructures of the welded joints and base metals were studied by means of opti-calmidoscope transmission electron microscope and microharlness.The expermental results Slow that the tensile strength of base metal can be improved by 30M Pa,and the tensile strength of the welded joint can be improved by 50M Pa.At the same time,the micnostnactures of recrystallization of the welded zone are fined due to addition of 0.21% Zr The tensile strength of the welded joint of A-l5.8Cu0.3Mn alloy is lower than that of tie base metal.In the welded joint the weld bead is the weakest area and the soften zone in tie heat affected zone is the second weakest where the θ' phase particle became coarser.