Hume-Rothery for HEA classification and self-organizing map for phases and properties prediction

The Hume-Rothery approach applied in terms of e/a to classify and design quasicrystals and BMG is revisited for the case of HEAs. The results were compared with other parameters used in the literature, namely VEC and delta. The Self-Organizing Map tool is used to classify the experimental results and the experimental map is used to compare the predictions of phases and properties of compositions reported in the literature. According to the Hume-Rothery approach, e/a and the average radius can give a precise rule of thumb to identify the domain of stability of HEAs and to estimate the phases that may occur in the alloy: i) e/a< 1.65: fcc, ii) 1.65 < e/a < 2.05: mixed phases, iii) e/a > 2.05: bcc. Moreover, e/a is to be preferred to VEC to classify phases in HEAs. Self-organizing maps can be used to make interpolative predictions for new compositions of HEAs with suitable phases for specific properties. Thus, simple combination of e/a and r gives an accurate first estimation to identify compositions with simple phases giving simple diffraction patterns, thus true HEAs as opposed to other compositional domains where complex phases occur.