Process and microstructure properties of laser beam welding of thin 2524 aluminum alloy sheet with filler wire

Type 2524 aluminum alloy is an Al-Cu-Mg alloy with high damage tolerance for aerospace applications. High power fiber laser welding of 1.6 mm thick 2524 aluminum alloy sheets was conducted with 5087 aluminum alloy filler wire. The effects of laser power,welding speed and wire feeding speed on the weld appearance,solidification cracking susceptibility and microstructure were investigated. The microhardness and mechanical properties of the crack-free joints were tested. The results indicate that welding with 5087 aluminum alloy filler wire could shorten the columnar dendritic grains,refine the equiaxed dendritic grains,increase the quantity of grain boundary and reduce the hot cracking susceptibility. A defect-free joint with good surface appearance was obtained with optimized welding parameters:2.5 kW laser power,2 m/min welding speed and 2 m/min wire feeding speed. The tensile strength of the joints was 313-324 MPa,and ductile fracture with plenty of dimples occurred around the weld fusion line.