Modeling of hierarchical solidification microstructures in metal additive manufacturing: Challenges and opportunities
Dilip K. Banerjee, Supriyo Ghosh, Julien Zollinger, Miha Zaloznik, Christopher Newman, Raymundo Arroyave
Metal-based additive manufacturing (AM) processes often produce parts with improved properties compared to conventional manufacturing and metal working routes. However, currently, only a few alloys can be reliably additively manufactured as the vast majority of the alloys in use today are not explicitly designed for this manufacturing route. This is because the highly non-equilibrium nature of melting and solidification phenomena during AM leads to undesirable microstructures with complex growth morphologies and unpredictable microstructural inhomogeneities including solidification defects, leading to unwanted variability in final material properties. In this context, the present work reviews the underlying physical mechanisms of microstructure and associated defects formation during ultrarapid cooling rates typical of AM in order to suggest approaches to minimize and control microstructural heterogeneities for improved printability and microstructure robustness (and hence properties). In particular, the physical effects of cooling rates and alloy parameters on rapidly moving complex solid-liquid interface shapes and the nucleation behavior during non-steady thermal conditions in heterogeneous liquid during AM need to be well-understood to control the solidification microstructure and grain morphology. Suitable integration of physics-rich macroscale melt pool, microstructure, and atomic-scale nucleation models (but benchmarked by experimental measurements) could potentially capture the above hierarchical AM phenomena that extend across multiple length scales and associated chemical heterogeneities. The multiscale multiphysics simulations would further guide parameter microstructure optimization via data-driven modeling and ultimately alloy development to suit a given AM application.
, Ghosh, S.
, Zollinger, J.
, Zaloznik, M.
, Newman, C.
and Arroyave, R.
Modeling of hierarchical solidification microstructures in metal additive manufacturing: Challenges and opportunities, Additive Manufacturing, [online], https://doi.org/10.1016/j.addma.2023.103845, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935917
(Accessed February 20, 2024)