The research, conducted by Dr Chinnapat Panwisawas (corresponding author) at Queen Mary School of Engineering and Materials Science, in collaboration with Pennsylvania State University (USA), Iowa State University (USA) and Shimane University (Japan), has been published in npj Computational Materials journal.

Nickel-based superalloy is a multi-component alloy having 10-15 elemental constitutes. A critical issue in laser powder bed fusion (LPBF) additive manufacturing is the selective vaporisation of alloying elements resulting in poor mechanical properties and corrosion resistance of parts. The process also alters the part's chemical composition compared to the feedstock.

Here we present a novel multi-physics modelling framework, integrating heat and fluid flow simulations, thermodynamic calculations, and evaporation modelling to estimate and control the composition change during LPBF of nickel-based superalloys. Experimental validation confirms the accuracy of our model.

Moreover, we quantify the relative vulnerabilities of different nickel-based superalloys to composition change quantitatively and we examine the effect of remelting due to the layer-by-layer deposition during the LPBF process. Spatial variations in evaporative flux and compositions for each element were determined, providing valuable insights into the LPBF process and product attributes.

The results of this study can be used to optimise the LPBF process parameters such as laser power, scanning speed, and powder layer thickness to ensure the production of high-quality components with desired chemical compositions.

Cite: Mukherjee, T., Shinjo, J., DebRoy, T., Panwisawas, C. Integrated modeling to control vaporization-induced composition change during additive manufacturing of nickel-based superalloys. npj Computational Materials 10, 230 (2024). https://doi.org/10.1038/s41524-024-01418-z