Mechanical Response Governed by Twinning‐Induced the Rotation of Twin Plane and Slip Plane in MnCuNiFe Alloy Under Dynamic Deformation

To understand the deformation mechanisms of MnCuNiFe alloy under dynamic deformation, the microstructure characteristics are investigated under strain rates up to 300 s −1 by using electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and X‐ray diffraction (XRD). The results show that the dynamic deformation of the alloy can be described by the Cowper–Symonds constitutive model DIF = 1 + (/637) 1/2· 08 , which is comparable to the response of steels governed by dislocation damping. It reveals that the total dislocation density correlates with the strain rate according to . The density of geometrically necessary dislocations (GNDs) increases progressively with strain rate, while the density of statistically stored dislocations (SSDs) shows a different variation tendency. Twinning induces slip plane rotation, leading to a reduction in the Schmid Factor that significantly impedes dislocation motion. It is proposed that the initial vibration attenuation is attributed to dislocation damping, and twinning‐induced twin plane rotation, as well as the deflection of the (111) slip system mitigates the fluctuations of subsequent stress waves. The equations proposed in the paper are crucial for predicting the dynamic behavior of this MnCuNiFe alloy.