Precipitate evolution in laser metal deposed Haynes 282 investigated using a combination of synchrotron scattering experiment and multi-scale modeling

The Ni-based superalloy Haynes 282 exhibits rapid γ ′ precipitation kinetics, and experimental studies have shown the formation of in-process precipitates in samples produced using the direct energy deposition additive manufacturing method, laser metal deposition (LMD). Understanding how these precipitates form and influence the final microstructure is essential for predicting and controlling the mechanical properties of processed Haynes 282. In this study, the particle size and volume fraction of γ ′ precipitates formed in LMD samples are simulated using classical nucleation and growth theory (CNGT). To account for the thermal history during manufacturing, the precipitate model is implemented as a multi-scale framework integrated into a finite element software. Calphad thermodynamic and diffusion data descriptions are used as input to the CNGT model to simulate the precipitation kinetics during different heat treatments. The simulated results are compared with experimental data obtained from small- and wide-angle X-ray scattering, as well as from atom probe tomography. The simulations show good agreement with experimental findings, demonstrating that thermodynamic databases can be used to accurately simulate precipitate evolution in LMD-processed Haynes 282 using CNGT.