Prediction of columnar and equiaxed grain morphologies during wire arc additive manufacturing of a Ti-Al-Fe-V alloy

This paper presents a method to couple a multicomponent Phase Field (PF) model with a process scale thermal Finite Element Analysis (FEA) model to predict columnar to equiaxed transition during Wire Arc Additive Manufacturing (WAAM). Specifically, a solidification process map is established through a series of phase-field simulations conducted under constant temperature gradient and solidification rate conditions. This map is then integrated with 3D finite element analysis simulations of the WAAM process to predict the formation of columnar or equiaxed grains as a function of build height under varying process conditions. The method is illustrated using a beta-Ti alloy, Ti-1Al-8V-5Fe (wt.%) with results from one processing condition validated against a 10-layer Ti-185 thin wall built using WAAM, showing consistent liquid pool depths. This approach offers an efficient framework for optimizing microstructure when additive manufacturing complex alloys.