Dynamic Tensile Deformation Mechanisms of Fe40Mn20Cr20Ni20 High-Entropy Alloys at Cryogenic Temperatures

Abstract:

The mechanical behavior and microscopic mechanism of the Fe₄₀Mn₂₀Cr₂₀Ni₂₀ high-entropy alloy (HEA) at high/cryogenic temperatures and high strain rates (split Hopkinson bar) were investigated, and relevant theoretical models were used to fit the yield strength and flow stress of HEA. The tensile test results show that HEA exhibits excellent strength-plasticity synergy and excellent work-hardening ability by reducing the temperature or increasing the strain rate. During the dynamic tensile process, the interactions between different forms of dislocations and deformation twins jointly improve the strength and work-hardening ability of HEA. The Zerilli-Armstrong constitutive model was used to predict the temperature sensitivity and strain-rate sensitivity of the yield strength of HEA. At the same time, the Taylor model was used to predict the flow stress change of HEA with the strain rate under dynamic tension, and the model was applied to low-temperature dynamic experiments. The fitting results are consistent with the experimental results, providing a theoretical basis for the subsequent prediction of HEA strength.