Manipulation of σy/κ ratio in single phase FCC solid-solutions

We investigate how to manipulate the ratio between thermal conductivity (kappa) and yield strength (sigma(y)) in face-centered cubic solid-solutions by varying the number of principal elements (NPEs) and temperature. The influence of NPEs on kappa and its electronic (kappa(e)) and lattice (kappa(l)) contribution is evaluated using the Wiedemann-Franz law. Positive Delta kappa/Delta T and the highest kappa(l)/kappa(e) ratio in high-entropy alloys (HEAs) can be understood by considering severe lattice distortion and compositional complexity. Among the solid-solutions from Ni to quinary alloys, the NiCoFeCrMn HEA exhibits the lowest kappa. However, sigma(y) increases with increasing NPEs and decreasing temperature. Thus, the NiCoFeCrMn HEA exhibits the highest sigma(y)/kappa ratio, higher than those of representative cryogenic alloys, which can be distinctively increased with a decrease in temperature. These results would give us a guideline on how to manipulate properties using HEA design concept in order to develop idealized cryogenic materials. Published by AIP Publishing.