The relationship between mechanical properties and microstructures of a metastable dual-phase high entropy alloy Fe₅₀Mn₃₀Co₁₀Cr₁₀ under uniaxial tensile testing at different strain rates (10^-3 s^-1∼10³ s^-1) has been studied systematically. As the strain rate increases, yield strength, ultimate tensile strength and uniform elongation decrease first and then increase. Namely, when the strain rate is 10^-3 s^-1, yield strength and ultimate tensile strength are 280 MPa and 720 MPa, respectively, with the uniform elongation of 64.2%. When the strain rate is increased to 1 s^-1, yield strength and ultimate tensile strength are 300 MPa and 672 MPa, respectively, and uniform elongation decreases to 49.2%. When the strain rate reaches 10³ s^-1, yield strength and ultimate tensile strength increase to 380 MPa and 810 MPa, respectively, while uniform elongation is elevated to 67%. As dynamic deformation is affected by the adiabatic heating, the stacking fault energy of the alloy is increased by ∼13 mJ m^-2 at a strain rate of 10³ s^-1 compared with that in the quasi-static condition. Under quasi-static loading, martensitic transformation is the dominant deformation mechanism. Under dynamic loading, when the strain is low the deformation induced phase transformation dominates, whereas as the loading proceeds mechanical twinning becomes the dominant deformation mode. At the same time, the adiabatic temperature rise under dynamic tests also causes a reverse transformation from ε-martensite to austenite. Accordingly, the release of internal stress and the formation of soft and ductile austenite jointly contribute to the elevated uniform elongation of the material. Both mechanical twinning and martensitic reverse transformation promote the microstructure to be dynamically refined, so that the alloy shows the good plasticity while maintaining the high ultimate tensile strength at dynamic strain rates.

所述亚稳双相高熵合金的Fe的机械性能和微观结构之间的关系₅₀的Mn ₃₀钴₁₀铬₁₀下单轴拉伸测试在不同应变率（10 ^-3小号^-1〜10 ^3个小号^-1）进行了系统研究。随着应变率的增加，屈服强度，极限抗拉强度和均匀伸长率先降低，然后增加。即，当应变率为10 ^-3 s ^-1时，屈服强度和极限抗拉强度分别为280 MPa和720 MPa，均匀伸长率为64.2％。当应变率增加到1 s ^-1时，屈服强度和极限抗拉强度分别为300 MPa和672 MPa，均匀伸长率降低至49.2％。当应变率达到10 ³ s ^-1时，屈服强度和极限抗拉强度分别增加到380 MPa和810 MPa，而均匀伸长率提高到67％。由于绝热加热会影响动态变形，因此在10 ³ s ^-1的应变速率下，合金的堆垛层错能增加了约13 mJ m ^-2。与准静态条件下相比。在准静态载荷下，马氏体相变是主要的变形机制。在动态载荷下，当应变较低时，变形引起的相变起主导作用，而随着载荷的进行，机械孪晶成为主要的变形模式。同时，在动态试验中绝热温度的升高也引起了从ε-马氏体到奥氏体的反向转变。因此，内部应力的释放以及软奥氏体和韧性奥氏体的形成共同有助于提高材料的均匀伸长率。机械孪晶和马氏体逆相变都促进了微观结构的动态细化，