Numerical and Experimental Analysis of the Influence of Manufacturing Parameters in Additive Manufacturing SLM-PBF on Residual Stress and Thermal Distortion in Parts of Titanium Alloy Ti6Al4V

Abstract

Additive manufacturing (AM) has become popular in recent years due to its integration with Industry 4.0 and for enabling the production of complex and optimized geometries. However, the process leads to disadvantages, such as thermal distortions and the generation of residual stresses due to thermal gradients during the parts production. Based on these undesirable characteristics, this work aims to model AM numerically through the Finite Element Method (FEM), besides obtaining experimental results that relate the impact of different process parameters, such as laser power, speed, and hatch distance on the residual stress and distortions distribution, to parts generated by Selective Laser Melting (SLM)—Powder Bed Fusion (PBF)—of titanium alloy Ti6Al4V. The experimental tests, as well as the numerical analyses, followed a factorial design. The results for thermal distortions are excellent with differences below 4.5% between the manufactured and simulated parts. As for the results of residual stresses measured at a single point on the lateral face, for most of the results, the difference was less than 4%; however, there was a large dispersion of results. When the values of average residual stresses were considered in the simulation, the results had statistical relevance and showed greater robustness. It was found that the average diameter of Ti6Al4V titanium parts was greatly influenced by the laser power followed by the hatch distance. The increase in power increased the average diameter of the samples, while the increase in speed and hatch decreased their diameter. In turn, increasing laser power decreased residual stress, while increasing speed and hatch tended to increase the mean residual stress. © The Rightsholder, under exclusive licence to [Springer Nature Switzerland AG], part of Springer Nature 2024.