Mesoscopic analysis of migration behavior for reinforcing microparticles of dual-laser powder bed fusion of TiC/Inconel 718 composites

The incorporation of ceramic particles into superalloys during dual-laser powder bed fusion (DL-PBF) is considered as an effective method to enhance the mechanical properties. However, the dynamic migration of reinforcements within pools under the action of dual lasers during the rapid nonequilibrium process remains challenging due to its complex physical thermodynamics. Based on the coupling methods of fluid dynamics and the discrete elements, the three-dimensional mesoscopic model of DL-PBF TiC/Inconel 718 composites where both of TiC and Inconel 718 particles were defined as the dispersed phase was developed to investigate the migration behavior of TiC particles. The results show that the migration of TiC particles is primarily induced by the thermal convention force as using a relatively low laser power, resulting in an agglomeration at the boundaries of solidification tracks or encountered areas of two lasers. Nevertheless, as a relatively high laser power is used, the TiC particles are migrated by the combined actions of rotated force produced by the interfacial conventions of liquid/reinforcements and thermal convention force. Moreover, the migration mechanism of TiC particles within pools during DL-PBF is also concluded, which offers a new insight into understanding the dynamics of incorporated reinforcements for the composite system.