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.

等原子的VCoNi中熵合金对晶界强化具有很高的敏感性，这是通过严重的晶格畸变实现的。即使是具有单面心立方结构的完全重结晶的合金，其超细晶粒结构也可实现1.5吉帕斯卡屈服强度。高的晶界密度还会通过堆积大量的位错而产生高的背应力，而低的横向滑动概率不仅会产生强的位错介导的可塑性，而且还会产生高的背应力对流变应力的作用，从而提供高的应变硬化能力到超细晶粒合金，极限拉伸强度达到1.7 Gigapascal，并具有出色的延展性。我们的方法为开发超强金属材料提供了一种新方法。