Insight into Cr Alloying on Face‐Centered Cubic to Body‐Centered Cubic Phase Transition in FeCr Alloy

Effects of Cr alloying on phase stability, magnetism, and electronic structures in both body‐centered cubic (bcc) and face‐centered cubic (fcc) phases and on the transformation from fcc to bcc are studied by first‐principles calculations. Results show that the doped Cr atoms in fcc and bcc phases choose distinct occupation models. This phenomenon can be understood from the amount of electron density of states close to Fermi energy. For magnetism, Cr tends to be antiferromagnetically coupled with the surrounding Fe in the studied phases. The magnetic moment of Fe is greater than that of Cr in bcc, but the order is reversed in fcc. The moment of Fe is dictated by the distance between it and the doped Cr in bcc, whereas it is dominated by spatial orientation with Cr in fcc. For phase stability, it is found that the alloying of Cr prefers destabilizing bcc while tends to stabilize fcc, leading to a strong inhibition of phase transition from fcc to bcc. Notably, the role in the fcc phase is more prominent than that in bcc, which can be associated with the antiferromagnetism between Fe and Cr in fcc.