Finite Element Analysis of Distortion and Residual Stress in Inconel 625 Produced by Laser Direct Energy Deposition

Laser direct energy deposition is a metal additive manufacturing process that produces three-dimensional components by scanning the laser layer by layer, with simultaneously injecting metal powder into a molten pool occurred by a high-energy laser directly. In this process, due to the localized heat input and rapid cooling of the deposit, complex residual stresses typically occurred within the deposited material. This study aimed to analyze the residual stress formation behavior during the laser direct energy deposition process of Inconel 625 alloy and to develop a finite element analysis model that can predict the residual stress. To experimentally investigate the residual stress formation behavior, a rectangular shaped substrate material was prepared, and Inconel 625 alloy with different thicknesses was deposited on top of the substrate material using two different deposition strategies of unidirectional and 90-degree tilted. The bending of the substrate material was measured to quantitatively analyze the residual stress. Based on the experimental results, a finite element model was designed to reproduce the residual stress of the Inconel 625 alloy produced by laser direct energy deposition process.