Exploring the Dynamic Transition from Aging to Additive Manufacturing: Investigating Microstructural Evolution of Metastable γ″ Precipitates in Inconel 625 through Coupled Phase-Field Simulation

Abstract

This study investigates the microstructural evolution during the coprecipitation of metastable γ″ (D022-Ni3Nb) particles within a supersaturated γ matrix in commercial IN625 Ni-based superalloy. The research aims to comprehensively understand the morphological evolution and fraction distribution of precipitate phases to enhance material strength and guide the design of additive manufacturing processes. A sophisticated coupled computational phase-field model is developed. The novel phase-field model within the open-source multiphysics object oriented simulation environment finite element framework enables the efficient construction of coupled phase-field mechanics models for multiphase systems. The quantitative precipitation model incorporates essential inputs, such as ab initio calculations, experimental data, precipitate–matrix orientation relationships, interfacial energy, interdiffusivities, and a tailored thermodynamic database. Simulation results reveal the intricate interplay of alloy composition, lattice misfit, external stress, temperature, and time, influencing the dynamic microstructure evolution during additive manufacturing. The findings highlight the significant influence of thermal cycles and process parameters on γ″ precipitate formation, directly impacting material properties and volumetric fraction. Leveraging experimental-driven formulations for coherent strength optimization aims to maximize γ″ precipitates while minimizing postprocessing costs.