Improving mechanical properties of wire plus arc additively manufactured maraging steel through plastic deformation enhanced aging response

摘要

Maraging steel gains ultrahigh strength through aging; however, wire plus arc additively manufactured maraging steel features a columnar-dendritic structure with associated segregation and shows a much less pronounced aging response. In this paper, plastic deformation was introduced through interpass cold rolling during the layer-by-layer deposition process. After aging, the ultimate tensile strength (UTS) was improved substantially from 1410 MPa (unrolled) to 1750 MPa (50 kN rolled). Rolling induced partial recrystallization to break the dendritic structure and form high-angle grain boundaries, which promoted the atoms diffusion to enable a more uniform solutionizing process and improved the subsequent aging response by 105-110%. The main contribution of overall strengthening of the rolled alloy was attributed to the effective aging process, accounting for more than 95% of the entire strength increase.