Formation Mechanism and Control of Solidification Cracking in Laser-Welded Joints of Steel/Copper Dissimilar Metals

The solidification cracking behavior in laser welds of steel/copper dissimilar metals was systematically investigated. T2 copper and SUS304 stainless steel were used the study. results showed that occurrence synergistic effect ? phase liquation, inclusions composition segregation. During welding process, liquation grain boundaries substantially reduced cohesion between adjacent grains, as well resistance for intergranular crack propagation. segregation inside grains could induce lattice distortion, thus reducing plastic deformation capacity material itself concurrently increasing susceptibility to cracks. In addition, an effective solution inhibiting proposed by using oscillating laser, inhibition mechanism further discussed. Laser significantly promoted refinement, solute diffusion formation uniformly distributed ?-Cu precipitated phases welds. It can improve bonding, reduce increase deformation. tensile strength joints is 251 MPa, 35.7% more than 185 MPa welding. Meanwhile, strain 3.69, a 96% compared 1.88