In this work, we report bulk nanostructured equiatomic FeCoNiCu high-entropy alloy (HEA) with superior thermal stability and decent mechanical properties. High pressure torsion (HPT) was employed to refine the grains in the HEA into nanoscale (80 nm), and then Cu-rich particles were in-situ introduced at grain boundaries by subsequent annealing (≥700 °C), forming a multi-phase nanostructure. The Cu-rich particles are highly stable at high temperatures and impose a pinning effect on the grain boundaries, which significantly restricts grain growth (grain size <500 nm up to 900 °C), thus leading to outstanding thermal stability. On the other hand, the nanostructures also possess high yield strengths of 643∼1165 MPa, mainly attributing to grain boundary hardening. Meanwhile, the in-situ formed Cu-rich particles can concurrently deform with the matrix during straining, resulting in large total elongation (15∼20%). This work provides a novel strategy for designing bulk nanostructured HEA with good thermal stability and mechanical properties.

在这项工作中，我们报告了块状纳米结构等原子 FeCoNiCu 高熵合金 (HEA)，具有优异的热稳定性和良好的机械性能。采用高压扭转（HPT）将 HEA 中的晶粒细化为纳米级（80 nm），然后通过随后的退火（≥700 ℃）在晶界原位引入富铜颗粒，形成多晶相纳米结构。富铜颗粒在高温下高度稳定，并对晶界施加钉扎效应，从而显着限制晶粒生长（晶粒尺寸 <500 nm 至 900 °C），从而具有出色的热稳定性。另一方面，纳米结构还具有 643∼1165 MPa 的高屈服强度，主要归因于晶界硬化。同时，现场形成的富铜颗粒在应变过程中会与基体同时变形，导致较大的总伸长率（15~20%）。这项工作为设计具有良好热稳定性和机械性能的块状纳米结构 HEA 提供了一种新策略。