An equiatomic VCoNi medium-entropy alloy possesses high sensitivity to grain-boundary strengthening, achieved by severe lattice distortions. Its ultrafine-grain structure enables 1.5 Gigapascal yield strength even for the fully recrystallized alloy with a single face-centered cubic structure. The high density of grain boundaries also generates high back stresses via piling up of massive dislocations, and the low cross-slip probabilities produce not only robust dislocation-mediated plasticity but also high back stress contribution to flow stress, which affords high strain-hardening capability to ultrafine-grain alloys, with 1.7 Gigapascal ultimate tensile strength with remarkable ductility. Our approach provides a new method for developing ultrastrong metallic materials.
CITATION STYLE
Park, J. M., Yang, D. C., Kim, H. J., Kim, D. G., Lee, S., Kim, H. S., & Sohn, S. S. (2021). Ultra-strong and strain-hardenable ultrafine-grained medium-entropy alloy via enhanced grain-boundary strengthening. Materials Research Letters, 9(7), 315–321. https://doi.org/10.1080/21663831.2021.1913768
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