To address the low yield strength of the Cr-Mn-Fe-Co-Ni high-entropy alloy (HEA) system, we employed a strategy of adding minor substitutional elements (SEs). Specifically, Cr₂₀Fe₂₀Co₂₀Ni₄₀ and Cr₂₀Fe₂₀Co₂₀Ni₃₅Al_2.5Si_0.5Cu₁Ti₁ HEAs were synthesized and studied to understand the impact of SEs on the mechanical properties and deformation mechanisms of the Cr-Mn-Fe-Co-Ni HEA system. The microstructures, mechanical behaviors, and deformation mechanisms of these alloys were characterized using scanning electron microscopy, transmission electron microscopy, atom probe tomography and other techniques. The results show that the minor SEs fully dissolve into the matrix, resulting in a solid solution strengthening effect of approximately 40 MPa without compromising ductility. The primary deformation mechanisms in both SE-free and SE-containing HEAs are dislocation slip, with the formation of dislocation cells contributing to the decent ductility observed in both alloys. Notably, the SEs-containing HEA annealed at 700°C exhibited annealing-induced hardening compared to the sample annealed at 600°C, which is attributed to the formation of L1₂ phases. These findings suggest that the addition of minor SEs can enhance solid solution strengthening and potentially modulate the deformation mechanism.

中文翻译：

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阐明微量取代元素对非等原子富镍高熵合金力学性能的影响

为了解决 Cr-Mn-Fe-Co-Ni 高熵合金 （HEA） 系统的低屈服强度问题，我们采用了添加微量取代元素 （SE） 的策略。具体来说，合成了 Cr ₂₀ Fe ₂₀ Co ₂₀ Ni ₄₀ 和 Cr ₂₀ Fe ₂₀ Co ₂₀ Ni Al _{35 2.5} Si _0.5 Cu ₁ Ti 高 ₁ 熵合金，以了解 SEs 对 Cr-Mn-Fe-Co-Ni 高熵合金体系力学性能和变形机制的影响。使用扫描电子显微镜、透射电子显微镜、原子探针断层扫描和其他技术表征了这些合金的微观组织、机械行为和变形机制。结果表明，少量 SE 完全溶解到基体中，在不影响延展性的情况下产生约 40 MPa 的固溶强化效果。无 SE 和含 SE 的高熵合金的主要变形机制是位错滑移，位错单元的形成有助于在两种合金中观察到良好的延展性。值得注意的是，与在 600°C 退火的样品相比，在 700°C 下退火的含 SEs 的 HEA 表现出退火诱导的硬化，这归因于 L1 ₂ 相的形成。这些发现表明，添加次要 SE 可以增强固溶体强化并可能调节变形机制。