Thermo-mechanical modeling and behavior analysis of titanium-matrix composites via laser powder bed fusion

Laser powder bed fusion (LPBF) gives new insights into the effective fabrication of multi-material parts. However, they have not reached mechanical reliability due to undesirable physical defects such as porosity related to powder spatter. The effect of a powder bed-substrate system with such defects on the thermo-mechanical behavior of multi-material parts is still unclear. In this paper, considering porosity due to powder spatter, a multi-material property model of titanium-matrix composites (TMCs) is established based on the mixture method. Considering temperature-dependent thermal properties, an integrated thermo-mechanical modeling of TMCs is developed to predict the residual stress and deformation of the as-built parts. The three-dimensional transient thermal and stress fields are predicted using the differential quadrature method (DQM). The predicted results show excellent agreement with the predictions and experimental results in the literature. Furthermore, the effect of process parameters, ceramic, part dimension, and porosity on the thermo-mechanical responses of TMCs is analyzed. The results show that the interface between the powder bed and substrate is subjected to the highest thermal gradient and residual stress. In addition, the thermal gradient, residual stress, and interfacial deformation increase with the increased energy density, porosity, and substrate thickness. These results can provide a guide for the design and manufacturing of multi-material parts via LPBF.