Solidification of Peritectic Alloys: a Computational Exploration

Objective

Advanced metallic alloys produced from recycled scrap can significantly reduce emissions, waste, and energy consumption. However, technological alloys with extreme chemical complexities impede the development of high-performance sustainable alloys. Microstructure-oriented alloy design opens promising avenues to guide the development of sustainable (i.e. leaner and less complex) alloys via tailoring the desired microstructure during solidification. Yet, while the development of dendritic and eutectic microstructures is relatively well understood, the comprehension of growth mechanisms of peritectic solidification (common to a broad range of alloy families) remains incomplete. The SPACE project will develop a quantitative phase-field model to investigate the emergence of complex growth patterns during peritectic solidification. To do so, we will (i) develop a quantitative multi-phase and multi-component nondiagonal phase field (MP-MC-NPF) model based on Onsager's relation, (ii) validate the model against sharp interface calculations and experimental observations, (iii) explore three-dimensional peritectic growth mechanisms at experimentally- relevant length and time scales (via GPU code acceleration), and (iv) study the effect of minor element addition (e.g. impurities from recycling) on microstructure growth and selection. We will focus, primarily, on binary Fe-Ni and ternary Fe-Ni-X alloys with high impact potential. The resulting MP-MC-NPF framework will shed light on the fundamental mechanisms of complex growth patterns and morphology transitions during peritectic solidification (for the first time in three dimensions and transient conditions) and thus contribute to the transition toward microstructure-oriented design of impurity-tolerant sustainable alloys.