Molecular Dynamics Simulation of Tensile Properties of FeCrNi Alloy Under High Strain Rates

The deformation mechanisms of a FeCrNi medium‐entropy alloy under extreme conditions involving high strain rates (5 × 10 ⁸ to 5 × 10 ¹⁰ s ⁻¹ ) and elevated temperatures (300 to 1300 K) were investigated via molecular dynamics simulations. At 300 K and a strain rate of 10 ¹⁰ s ⁻¹ , the alloy exhibited a Young's modulus of 186.5 GPa and a tensile strength of 29.3 GPa. Microstructural analysis revealed a deformation‐induced phase transformation from FCC to HCP/BCC, accompanied by twinning and stacking fault formation. Increasing the temperature to 1300 K reduced the elastic modulus by 8.1% and the tensile strength by 28.6%, as high temperatures suppressed the ordered HCP phase transformation (HCP fraction dropped from 17.4% to 7.6%) and accelerated amorphization. Conversely, increasing the strain rate enhanced the tensile strength by up to 14.2%, with lower rates promoting the FCC‐HCP transition and higher rates inhibiting it. These atomic‐scale insights clarify the competition between phase transformation and amorphization, guiding the design of MEAs for extreme service conditions.