Modeling of phase transformation kinetics in Ti-6Al-4V alloy during additive manufacturing

A. BOCCARDO; Y. XINYU; D. TOURRET; J. SEGURADO; M. TONG; S. LEEN

Congreso; 2022 TMS Annual Meeting & Exhibition; 2022

AdditiveManufacturing allows building metallic components of great topologicalcomplexity. However, the successive deposition and melting of material layersinvolves a convoluted thermal cycling with high heating and cooling rates,gradually decreasing as layers are added, which often results in multipleconcurrent phase transformations. In this work, we study the phasetransformations occurring in a Ti-6Al-4V alloy during fusion-based additivemanufacturing (e.g. selective laser melting). These transformations include thetransformation from a β phase into a metastable α’ martensite due to the rapidcooling after the layer deposition, followed by the α’ martensite decomposing(partially or totally) into an α+β structure during the cyclic temperatureevolution. We combine different models (e.g. Avrami-based and phase-field) tosimulate these solid-state transformations, paying special attention to thekinetics of martensite decomposition. Our simulation results are compared to experimental measurements toevaluate and discuss the accuracy, performance, and limitations of the models.