Abstract

We investigated the effects of hydrogen and temperature on hydrogen embrittlement (HE) of cold-rolled equimolar CoCrFeMnNi high-entropy alloy (HEA). The HE exhibited intergranular fracture in this HEA at 298 and 177 K. At 177 K, more twins formed than at 298 K, and this acted as a hydrogen-diffusion path. During deformation, local stress was concentrated at the triple junction consisting of grain and twin boundaries. Hydrogen diffused predominantly along the boundary and encountered stress-concentration regions. Cracks initiated and propagated predominantly through the grain/twin boundaries by hydrogen diffusion at 298 and 177 K. Therefore, HE occurred at 298 and 177 K. At 77 K, hydrogen was distributed throughout the specimen as twin formation was more active. The cryogenic temperature of 77 K caused the hydrogen to become trapped and thus not diffuse into the stress-concentration region. Thus, there was no significant HE at 77 K.

Graphic abstract

中文翻译：

---

氢和温度在等摩尔CoCrFeMnNi高熵合金氢脆中的作用

摘要

我们研究了氢气和温度对冷轧等摩尔CoCrFeMnNi高熵合金（HEA）的氢脆性（HE）的影响。HE在298和177 K时在HEA中显示出晶间断裂。在177 K时，形成的孪晶比在298 K时多，并且这是氢扩散的路径。在变形过程中，局部应力集中在由晶界和孪晶界构成的三重结处。氢主要沿边界扩散并遇到应力集中区域。由于氢在298和177 K处的扩散，裂纹主要通过晶粒/孪晶边界发生并扩展。因此，HE在298和177 K处发生。在77 K处，氢随着整个孪晶的形成更加活跃而分布在整个试样中。77 K的低温使氢被捕获，因此没有扩散到应力集中区域。因此，在77 K时没有明显的HE。

图形摘要