Atomistic simulations of compressive response and deformation mechanisms of body-centered-cubic AlCrFeCoNi high-entropy alloys

Atomistic simulations are performed to study the compressive response and deformation mechanisms of the body-centered-cubic (BCC) AlCrFeCoNi high-entropy alloys (HEAs). Our computations show that the BCC HEA mainly experiences three typical deformation stages, i.e. linear elastic, plastic yielding, and yield flow regimes, and the predicted Young's modulus and yield strength agree well with available experiments. The plastic deformation mechanism of BCC HEA is dominated by the dislocation nucleation and slip accompanied by shear bands but depends little on the phase transformation of the HEAs. Compared with the face-centered-cubic counterpart, the BCC HEA is harder and more brittle due to the less dislocation activities in the alloy. In addition, the dependences of mechanical properties and deformation mechanisms on influential factors including temperature, strain rate, and Cr concentration are also analyzed in detail. These findings may deepen our understanding of the underlying deformation mechanisms in BCC HEAs.