The current work compares the deformation behavior of CoCrFeMnNi and CoCrNi in the temperature interval between 295 K and 8 K through a series of quasi-static tensile tests. Temperature-dependent yield stress variation was found to be similarly high in these two alloys. Previous investigations only extended down to 77 K and showed that a small amount of ε-martensite was formed in CoCrNi while this phase was not observed in CoCrFeMnNi. The present study extends these investigations down to 8 K where similar low levels of ε-martensite were presently detected. Based on this result, a rough assessment has been made estimating the importance of deformation twinning to the strength. The relative work hardening rates of CoCrFeMnNi and CoCrNi were comparable in value despite the differences in ε-martensite formation during deformation. CoCrFeMnNi deforms by dislocation slip and deformation twinning while deformation in CoCrNi is also accommodated by the formation of ε-martensite at cryogenic temperatures. Additionally, CoNi, a solid solution from the Co–Cr–Fe–Mn–Ni system with low strength, was used for comparison, showing contrasting deformation behavior at cryogenic temperatures.

通过一系列准静态拉伸测试，当前工作比较了295 K和8 K之间温度区间内CoCrFeMnNi和CoCrNi的变形行为。在这两种合金中，发现随温度变化的屈服应力变化同样较高。先前的研究仅延伸至77 K，并且表明在CoCrNi中形成了少量的ε-马氏体，而在CoCrFeMnNi中未观察到该相。本研究将这些研究扩展到了8 K，目前已检测到类似水平的低水平的马氏体。基于此结果，已进行了粗略的评估，以估计变形孪生对强度的重要性。尽管在变形过程中ε马氏体的形成有所不同，但CoCrFeMnNi和CoCrNi的相对加工硬化率在数值上是可比较的。CoCrFeMnNi因位错滑移和变形孪生而变形，而CoCrNi中的变形也因在低温下形成ε-马氏体而得以适应。另外，CoNi是来自Co-Cr-Fe-Mn-Ni系统的低强度固溶体，用于比较，显示出在低温下的对比变形行为。