Deformation Mechanisms and Predictive Modeling of AlCoCrFeNi HEA under Hot Working Conditions

This study unveils novel insights into the hot deformation behavior of AlCoCrFeNi high-entropy alloy (HEA), emphasizing its unique dual-phase microstructure and deformation mechanisms. The alloy’s stable microstructure, featuring a BCC matrix with alternating disordered BCC and ordered B2 lamellae and an FCC secondary phase, remained consistent across all deformation conditions, showcasing exceptional microstructural stability. A key novelty lies in the identification of FCC/BCC interfaces as critical contributors to strain hardening, revealed through molecular dynamics simulations. Additionally, TEM analysis provided unprecedented details on substructural evolution within the ordered B2 phase, including dislocation cell walls, wavy slip, and entanglements, offering new perspectives on deformation mechanisms in HEAs. A machine learning model was developed to accurately predict flow stress by capturing the complex nonlinear dependencies on deformation parameters, offering a robust predictive tool. These findings advance the understanding of HEAs, highlighting the intricate interplay between microstructure, phase interfaces, and dislocation dynamics under thermomechanical processing, with implications for designing high-performance alloys.