Low cycle fatigue behavior of ${\mathrm{F}\mathrm{e}}_{50}{\mathrm{M}\mathrm{n}}_{30}{\mathrm{C}\mathrm{o}}_{10}{\mathrm{C}\mathrm{r}}_{10}$ metastable dual-phase (FCC + HCP) high entropy alloy is characterized by deformation-induced martensitic transformation from FCC to HCP phase at lower strain amplitude of 0.3% and 0.6% while at higher strain amplitude of 0.9% and 1.2%, profuse extension twinning in HCP phase is observed with some reverse HCP to FCC transformation. The presence of multiple deformation mechanisms like planar slip and deformation twinning in both the phases along with bidirectional phase transformation contributes to a hierarchically refined microstructure. This provides an avenue for microstructural engineering to achieve excellent tensile and low cycle fatigue performance of ${\mathrm{F}\mathrm{e}}_{50}{\mathrm{M}\mathrm{n}}_{30}{\mathrm{C}\mathrm{o}}_{10}{\mathrm{C}\mathrm{r}}_{10}$.

低周疲劳行为 ${\mathrm{F}\mathrm{电子}}_{50}{\mathrm{米}\mathrm{n}}_{30}{\mathrm{C}\mathrm{○}}_{10}{\mathrm{C}\mathrm{r}}_{10}$亚稳态双相 (FCC + HCP) 高熵合金的特征是在 0.3% 和 0.6% 的较低应变幅下从 FCC 到 HCP 相的变形诱导马氏体相变，而在 0.9% 和 1.2% 的较高应变幅下，大量拉伸孪晶在 HCP 阶段观察到一些反向 HCP 到 FCC 转化。两相中存在多种变形机制，如平面滑移和变形孪晶以及双向相变，有助于分层细化微观结构。这为微结构工程提供了一条途径，以实现优异的拉伸和低周疲劳性能。${\mathrm{F}\mathrm{电子}}_{50}{\mathrm{米}\mathrm{n}}_{30}{\mathrm{C}\mathrm{○}}_{10}{\mathrm{C}\mathrm{r}}_{10}$.