Residual stress and part distortion prediction in L-PBF of Ti-6Al-4V using layer-by-layer FEM simulation

Abstract

Due to its ability to accommodate customer demands and produce objects with complex shapes, Laser Powder Bed Fusion (LPBF) has been widely adopted in numerous industry areas, including biomedical, automotive, and aerospace. Even with all the benefits that LPBF has to offer, its use may be limited by the development of residual stress according to the strong thermal gradients produced throughout the process. Residual stresses within the samples can result in part distortion after the removal from the built platform or even in part failure during the process if the residual stresses are excessive. In order to save time and costs, numerical simulation can be an effective tool to predict residual stress and part distortion in opposition to the trial-and-error approach which involves an expansive and time-consuming experimental campaign. To this aim a finite element method (FEM) together with a layer-by-layer approach was used in this study. Numerical simulations were performed on the commercial software DEFORM-3D™ with which different values of laser power were investigated. Moreover, the influence of the voxel mesh on the FEM model accuracy was also investigated.