Precipitation Simulations of the O‐Phase in Ti ₂ AlNb Alloys Processed by Laser Powder Bed Fusion

In this work, computational models for phase precipitation were used to simulate the evolution of the O‐phase volume fraction during postprocessing of a Ti‐21Al‐25Nb (at.%) alloy processed by laser powder bed fusion and to study the phase transformations during subsequent heat treatments. The combination of computational simulations, thermodynamic models, and own experimental analysis allowed us to understand the sluggishness of the O‐phase isothermal precipitation in this alloy. To arrive at these conclusions and ensure that the simulations provided meaningful results, a thorough analysis of the input parameters was required to set up the calculations. A sensitivity analysis allowed quantification of the influence of these parameters on the phase fraction evolution. The interfacial energy of the matrix and precipitate phases was identified as the most relevant input parameter for the simulation of the volume fraction evolution during the aging process. This case study illustrates that computational thermodynamic and precipitation analysis provides a strong complementarity with experimental studies, enabling to tackle specific questions that are difficult to answer by designed experiments and even predict materials’ behavior.