A fully transient discrete-source 3D additive manufacturing (AM) process model was coupled with a 3D stochastic solidification structure model for quick, efficient, and accurate prediction of the grain structure evolution in Ti-6Al-4V alloy processed via Laser Powder Bed Fusion (LPBF). The stochastic model was adapted to rapid solidification conditions of multicomponent alloys processed via multi-layer multi-track AM. The capabilities of the coupled model include studying the effects of process parameters (power input, speed, beam shape) and part geometry on solidification conditions and their impact on the resulting solidification structure evolution. The multi-scale model assumes that the complex combination of the crystallographic requirements, isomorphism, epitaxy, changing direction of the melt pool motion and thermal gradient direction will produce the observed texture and grain morphology. Thus, grain size, morphology, and crystallographic orientation can be assessed, and the model can assist in achieving better control of the solidification microstructures and to establish trends in the solidification behavior in AM components. The coupled model was validated against single-layer LPBF IN625 experiments previously performed and analyzed at National Institute of Standards and Technology (NIST). This 3D modeling approach can also be used to predict the solidification structure of Ti-6-4 alloys in Electron Beam AM processes.

Moderated by: Hani Henein / Mark Jolly