Influence of Processing Parameters and Post Heat Treatment on Mechanical Properties of AISI 1025 Fabricated by Laser Engineered Net Shaping

Abstract

A 3D coupled thermomechanical model was developed to investigate the evolution of residual stress in AISI 1025 fabricated by Laser Engineered Net Shaping (LENS). The model, validated experimentally with an error margin of 4.24%, demonstrated reliable predictive capability. Process parameters strongly influenced mechanical performance, with optimal settings (270 W laser power and 7.1 mm/s scan speed) achieving a hardness of 169.17 HV, a relative density of 99.78%, and minimal porosity (0.91%). Residual tensile stresses was reduced to 131.83 MPa, accompanied by a refined microstructure. Post-processing revealed contrasting effects: quenching improved hardness by 22% due to martensite formation, but induced high tensile stresses (425 ± 14 MPa), whereas annealing at 850°C reduced residual stress by over 90%, improving crack resistance while lowering hardness by 25%. These findings highlight annealing as an effective strategy for stress relief, making AISI 1025 well suited for tool and die applications, particularly in filament production for Fused Deposition Modeling (FDM).