Study on the Mechanical Response and Deformation Mechanisms of AlxCoCrFeNi High-Entropy Alloys

JC Li and YY Chen and ZY Fang and ZK Wei and JQ Ren and HT Xue and XF Lu and FL Tang, JOM, 77, 8083-8100 (2025).

DOI: 10.1007/s11837-025-07715-2

This study investigates the tensile mechanical behavior and deformation mechanisms of AlxCoCrFeNi high-entropy alloys (HEAs) through molecular dynamics (MD) simulations, with a specific focus on the influences of Al content, temperature, and strain rate. The results demonstrate that, with increasing strain, the face-centered cubic (FCC) structured atoms in the system are progressively transformed into hexagonal close-packed (HCP), body-centered cubic (BCC), and other disordered atoms, while the dislocation density increases significantly, with Shockley partial dislocations dominating. After yielding, a substantial number of stacking faults (SFs) and twins are generated, which dominate the process of plastic deformation. Increasing Al content and temperature markedly reduce the Young's modulus and yield strength of the alloys. The decrease in unstable stacking fault energy (gamma USF) due to high Al content leads to early activation of dislocation slip, while the high temperature environment exacerbates the lattice disorder by enhancing atomic mobility. The elevated strain rate does not affect the Young's modulus, but there is a slight enhancement of the yield strength by increasing the dislocation density and strengthening the dislocation entanglement. This study provides a theoretical foundation for the tensile mechanical response and deformation mechanisms of AlCoCrFeNi HEAs.

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