Evolution of strain field in laser-repaired stainless steel/nickel-based heterogeneous alloy

In this study, the strain field evolution mechanism of laser-repaired 304 stainless steel /In718 heterogeneous structure was studied using EBSD technique. The results show that the strain concentration in the repaired zone is much smaller than that in the substrate zone. As the laser power increases from 900 W to 1100 W, the strain concentration in the repaired zone and the substrate zone increases significantly. The different strain concentration in the repaired region and the substrate region is mainly related to the increase of lattice distortion, dislocation density and temperature gradient. In addition, because the grains with different orientations have different Taylor factor, and therefore, grain orientation is also key factor affecting the strain concentration.