Integrated Materials Modeling of Laser Additive Manufacturing Processes

In recent years, the interest in additive manufacturing processes has grown significantly due to their unique attractive attributes and versatility.  Laser-based additive processes span a plethora of complex physical mechanisms which must be modeled accurately to successfully predict performance of a manufactured product. Despite the inherent correlation between material and performance, typical continuum-based models neglect to capture the impact of material properties throughout the manufacturing process on the performance of the final product.  Successful simulation of a laser-based manufacturing process requires a substantial knowledge base spanning both a breadth and depth of engineering and science.

This talk provides latest development in predictive modeling capabilities for laser-additive manufacturing processes.  The integrated model presented here considers laser-material interaction, melting and solidification, microstructure evolution, solid state phase transformation and the resultant residual stresses.   A comprehensive laser deposition model was employed to acquire information regarding the geometry and temperature profile of H13 tool steel powder/substrate at steady state conditions. These results were then applied to a kinetic model that predicts solid phase transformation in hypoeutectoid steels and accounts for non-isothermal heating, carbon diffusion, cooling rate, and multi-track tempering. The temperature, solidification geometry, and solid phase history are then applied to a finite element model that predicts the residual stress based on thermal expansion and phase transformational strains. Model results were validated against experimental data.