Microstructure development during rapid alloy solidification

Journal Article · 13 May 2024 · MRS Bulletin

DOI: https://doi.org/10.1557/s43577-024-00717-6 · OSTI ID:2350715

Ji, Kaihua; Clarke, Amy J.; McKeown, Joseph T.; Karma, Alain

Abstract Solidification processing of structural alloys can take place over an extremely wide range of solid–liquid interface velocities spanning six orders of magnitude, from the low-velocity constitutional supercooling limit of microns/s to the high-velocity absolute stability limit of m/s. In between these two limits, the solid–liquid interface is morphologically unstable and typically forms cellular-dendritic microstructures, but also other microstructures that remain elusive. Rapid developments in additive manufacturing have renewed the interest in modeling the high-velocity range, where approximate analytical theories provide limited predictions. In this article, we discuss recent advances in phase-field modeling of rapid solidification of metallic alloys, including a brief description of state-of-the-art experiments used for model validation. We describe how phase-field models can cope with the dual challenge of carrying out simulations on experimentally relevant length- and time scales and incorporating nonequilibrium effects at the solid–liquid interface that become dominant at rapid rates. We present selected results, illustrating how phase-field simulations have yielded unprecedented insights into high-velocity interface dynamics, shedding new light on both the absolute stability limit and the formation of banded microstructures that are a hallmark of rapid alloy solidification near this limit. We also discuss state-of-the-art experiments used to validate those insights. Graphical abstract

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0020895; SC0020870; AC52-07NA27344; 89233218CNA000001
• OSTI ID: 2350715
• Alternate ID(s): OSTI ID: 2375437; OSTI ID: 2406653
• Journal Information: MRS Bulletin, Journal Name: MRS Bulletin Journal Issue: 6 Vol. 49; ISSN 0883-7694
• Publisher: Cambridge University Press (CUP)Copyright Statement
• Country of Publication: United States
• Language: English