Short-range order and phase stability of CrCoNi explored with machine learning potentials
Sheuly Ghosh, Vadim Sotskov, Alexander V. Shapeev, Jörg Neugebauer, Fritz Körmann
Abstract
We present an analysis of temperature-dependent atomic short-range ordering and phase stability of the face-centered cubic CrCoNi medium-entropy alloy employing a combination of ab initio calculations and on-lattice machine learning interatomic potentials. Temperature-dependent properties are studied with canonical Monte Carlo simulations. At around 975 K a phase transition into an ordered $\mathrm{Cr}{(\mathrm{Ni},\mathrm{Co})}_{2}$ phase (${\mathrm{MoPt}}_{2}$-type) is found. This hitherto not reported state has an ordering energy twice as large than the ordered structures previously suggested. We show that magnetism is not responsible for the observed chemical ordering.