Crucial feature space for ductile bcc high-entropy alloys

Abstract

Body-centered cubic (bcc) high-entropy alloys (HEAs) are promising structural materials for nuclear power plants to ensure good radiation resistance. However, the majority of bcc HEAs show limited room temperature ductility even in compression. In addition to the compressive properties of as-cast high-activation bcc HEAs collected from the literature, those of low-activation ones were investigated by phase diagram calculations and experiments. Therefore, a consistent dataset comprising 93 samples was generated. A classification and regression tree (CART) algorithm was employed to differentiate the target bcc HEAs with a compressive failure strain of more than 50% from the others. The model generality of a finalized CART classifier was validated by training and testing F1 scores and accuracies. It was found that Pugh's ratio (κ) and valence electron concentration (VEC) are two key attributes to identify the target alloys. The crucial κ-VEC feature space displays that the targets are generally located in the region where κ is larger than 3.129 or VEC is larger than 6.296. Especially, high-activation and low-activation samples seem to have opposite characteristics, motivating the further study of a deformation mechanism for low-activation bcc HEAs.