Study on microstructure and composition segregation of laser welded joints of 2A14 aluminum alloy

Laser welding is an attractive welding process for aluminum alloys, because its low heat input minimizes the width of fusion zone (FZ) and heat affected zone (HAZ). The present research is mainly concerned with the effect of welding parameters on microstructure morphology, composition segregation microhardness and tensile test of laser welding of 2 mm thickness 2A14 aluminum alloy. The results show that the welded joint with good quality can be achieved when the laser power is 2.5 kW and the welding speed is 2.4 m min⁻¹. The center of the weld seam exhibits fine equiaxed grains, while the FZ consists of coarse columnar crystals and Cu segregates at the boundary of the columnar crystals. And the tensile strength of sample 4 is 274.3 MPa and about 74.4% of that of BM, which is higher than that of 3 samples. In addition, the welding speed has greater influence than the laser power on the microhardness of the joints. (paper)