Fatigue-crack blunting mediated by high-density dislocations in a CrMnFeCoNi high-entropy alloy at intermediate temperatures

W Li and F Tan and X Li and B He and C Jiang, MATERIALS CHARACTERIZATION, 230, 115680 (2025).

DOI: 10.1016/j.matchar.2025.115680

The synergistic mechanical and thermal effects on the fatigue crack growth in a CrMnFeCoNi high-entropy alloy (HEA) are investigated at an intermediate temperature of 673 K. It is found that fatigue cracking exhibits a largescale sharpening-blunting-resharpening behavior under cyclic loading. Crack tip blunting reduces the local stress intensity, thereby contributing to a dynamic fatigue resistance mechanism. Microstructural characterizations indicate that the accumulation and movement of high-density dislocation groups play an important role in modulating the fatigue-crack blunting. Molecular dynamics simulations reveal the important role of severe lattice distortion and intense thermal activation at 673 K in controlling dislocation dynamics and promoting the crack tip blunting.

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