High-entropy alloys exhibit exceptional mechanical properties at cryogenic temperatures, due to the activation of twinning in addition to dislocation slip. The coexistence of multiple deformation pathways raises an important question regarding how individual deformation mechanisms compete or synergize during plastic deformation. Using in situ neutron diffraction, we demonstrate the interaction of a rich variety of deformation mechanisms in high-entropy alloys at 15 K, which began with dislocation slip, followed by stacking faults and twinning, before transitioning to inhomogeneous deformation by serrations. Quantitative analysis showed that the cooperation of these different deformation mechanisms led to extreme work hardening. The low stacking fault energy plus the stable face-centered cubic structure at ultralow temperatures, enabled by the high-entropy alloying, played a pivotal role bridging dislocation slip and serration. Insights from the in situ experiments point to the role of entropy in the design of structural materials with superior properties.

高熵合金在低温下表现出卓越的机械性能，这是由于除了位错滑移之外，孪晶的活化。多个变形路径的​​共存提出了一个重要的问题，即在塑性变形过程中各个变形机制如何竞争或协同作用。使用原位中子衍射，我们证明了高熵合金在15 K时多种变形机制之间的相互作用，其始于位错滑移，然后是堆垛层错和孪晶，然后通过锯齿转变为不均匀变形。定量分析表明，这些不同变形机制的共同作用导致极端的加工硬化。在超低温度下的低堆垛层错能加上稳定的面心立方结构，通过高熵合金化，在位错滑移和锯齿之间架起了关键作用。原位实验的见解指出了熵在具有优异性能的结构材料设计中的作用。