Physics of Particle Impact During Direct Energy Deposition Additive Manufacturing

Professor: Atieh Moridi

Project Description: Additive manufacturing (AM) of metallic materials, including laser powder bed fusion (PBF) and direct energy deposition (DED), has seen tremendous growth recently. One of the major roadblocks in adopting AM technologies, especially in safety-critical engineering structures such as turbine blades, biomedical and energy storage devices, is poor repeatability of the process due to many competing factors influencing the properties of the deposit. For powder fed DED in particular, the effect of fast heating and cooling rate due to localized laser processing and the stochastic nature of interactions between powders (with different sizes and shapes, velocities, and trajectories) with shape-changing, dynamic melt pool (due to Marangoni convection, laser recoil force, and the shear stress in the gas-melt interface) gives rise to inhomogeneity in structure and, as a result, in properties. In this project, we plan to study the effects of nozzle exit geometry, powder impact velocity, powder properties (particle size, density, and shape), and powder feeding parameters (powder feeding rate and carrier-gas flow rate) on the characteristics of the powder flow and entrapment in the melt pool. (This project is offered In-Person)