A Criterion for Topological Close-Packed Phase Formation in High Entropy Alloys

The stability of topological close-packed (TCP) phases were found to be well related to the average value of the d-orbital energy level ( [GRAPHICS] ) for most reported high entropy alloys (HEAs). Excluding some HEAs that contain high levels of the elements aluminum and vanadium, the results of this study indicated that the TCP phases form at [GRAPHICS] > 1.09. This criterion, as a semi-empirical method, can play a key role in designing and preparing HEAs with high amounts of transitional elements.