Plastic deformation transition in FeCrCoNiAlx high-entropy alloys

Abstract

The competition between plastic deformation mechanisms in FeCrCoNiAlx high-entropy alloys is explored as a function of temperature by first-principle theory. Investigating the generalized stacking fault energy, we identify a strong interplay between the magnetic and chemical effects. At cryogenic conditions (ferromagnetic state), full-slip is accompanied by martensitic transformation, whereas increasing temperature towards room-temperature (paramagnetic state) changes the deformation mechanism to full-slip plus twinning. Alloying with Al reduces the susceptibility for stacking fault formation in the ferromagnetic state and promotes twinning in the paramagnetic state. The present advance in magneto-plasticity reveals new opportunities for tailoring the mechanical response in high-entropy alloys. IMPACT STATEMENT: Magnetic state critically affects the γ-surface of FeCrCoNiAlx and is responsible for the emergence of the exceptional metastable twinning phenomena at room temperature.