Benchmark study of melt pool and keyhole dynamics, laser absorptance, and porosity in additive manufacturing of Ti-6Al-4V

Metal three-dimensional (3D) printing involves a multitude of operational and material parameters that exhibit intricate interdependencies, which pose challenges to real-time process optimization, monitoring, and controlling. The dynamic behavior of the laser-induced melt pool strongly influences the final printed part quality by controlling the absorption of laser power and impacting defect creation, porosity, and surface finish. By leveraging ultrahigh-speed synchrotron X-ray imaging and high-fidelity multiphysics modeling, we identify correlations between laser process parameters, keyhole and melt pool morphologies, laser absorptance, and porosity in metal 3D printing of Ti-6Al-4V, aiding in the development of effective printing strategies. Our models accurately predict the geometries and shapes of melt pools and keyholes, laser absorptance, and the size and shape of keyhole-induced pores during the additive manufacturing processes using different laser parameters, for both bare and powder cases. This work establishes robust correlations among process parameters, melt pool and keyhole morphology, and materials properties. These findings provide valuable insights into the complex interplay among different design factors in metal 3D printing, laying a strong foundation for the development of highly effective and efficient additive manufacturing processes.