Interaction between dislocations and L12 precipitates in the Al0.3CoCrFeNi high-entropy alloy during nanoscratching

MG Wang and DP Hua and JC Li and ZC Jiao and LH Zhu and MD Xie and YX Zhu and TE Huang and WT Ye and NM Lin and D Qian and Q Zhou and HF Wang, TRIBOLOGY INTERNATIONAL, 211, 110880 (2025).

DOI: 10.1016/j.triboint.2025.110880

The Al0.3CoCrFeNi high-entropy alloy (HEA) containing L12 precipitates (Ni3Al) has garnered significant attention due to their exceptional mechanical properties and cost-effectiveness. While the strengthening effects of L12 precipitates on mechanical performance are well- documented, their role in tribological behavior remains underexplored. This study employs molecular dynamics (MD) simulations to systematically investigate the influence of L12 precipitates on the nanoscratching behavior of Al0.3CoCrFeNi HEA. Comparing the substrate without L12 precipitates, L12 precipitates alter dislocation dynamics, reducing total dislocation length while enhancing tribological performance. Debris atoms exhibit a more uniform morphology and reduced pile-up height, leading to a lower wear rate. In addition, increasing scratch velocity and deeper scratches all intensify dislocation-precipitate interactions, promoting residual dislocations in L12 precipitates and asymmetric debris distribution. In particular, the interaction between dislocation and L12 precipitates during nanoscratching was revealed by the well-designed shear simulation. L12 precipitate exerts a delaying effect on dislocation motion rather than a pinning effect, which can improve strength while maintaining ductility. Meanwhile, the strengthening effect of L12 precipitates exhibits an overall upward trend as the dislocation cuts through multiple times, which provides potential work hardening ability. These results elucidate the dual role of L12 precipitates in enhancing both strength and wear resistance, providing critical insights for designing high-performance HEAs.

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