High Entropy Alloys (HEAs) are a new class of alloys having impressive mechanical properties . Here, a mechanistic, parameter-free, and predictive theory for the temperature-, strain-rate-, and composition-dependence of the plastic yield strength of fcc HEAs is presented and applied to understand recent experiments . Each elemental component in the HEA is considered as a solute embedded in the effective matrix of the surrounding alloy. Strengthening is then achieved due to dislocation interactions with the random local concentration fluctuations around the average composition. Yield strengths in Ni-Co-Cr-Fe fcc HEAs are predicted using only available experimental information, achieving good quantitative agreement. The theory demonstrates the origins of the high strength, the high-temperature “plateau strength”, the detailed observed trends, and identifies the key material properties needed for computational design and optimization of HEAs.
Y. Zhang et al., Prog. Mat. Sci. 61, (2014).
C. Varvenne, A. Luque and W.A. Curtin, submitted.