Effect of heat treatment on microstructure and mechanical properties of 17-4PH stainless steel manufactured by laser-powder bed fusion

The 17-4 precipitation-hardened (PH) stainless steel was prepared by laser-powder bed fusion (L-PBF), and the effects of different aging temperatures on the microstructures and properties of 17-4PH stainless steel were systematically studied. The results show that the 17-4PH stainless steel prepared by laser powder bed fusion requires a solid solution treatment in order to obtain the lath martensite structure, and then the niobium carbides and epsilon-Cu phase nanoparticles were precipitated by aging treatment to improve the strength of 17-4PH stainless steel. When the aging heat treatment parameter is 450 degrees C/5 h, the mechanical properties of the 17-4PH stainless steel are better, and the ultimate tensile strength (UTS) and elongation (El) are 1387 MPa and 7.3%, respectively. Compared with the as-printed 17-4PH stainless steel, the ultimate tensile strength of aging heat treatment exhibits an increase of 25.2%, and then, as the increase of aging temperature, the niobium carbides and epsilon-Cu precipitation phase become coarser, resulting in a decrease in the strength of 17-4PH stainless steel and an increase in plasticity.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).