Temperature Effects on Deformation and Serration Behavior of High-Entropy Alloys (HEAs)

Many materials are known to deform under shear in an intermittent way with slip avalanches detected as acoustic emission and serrations in the stress-strain curves. Similar serrations have recently been observed in a new class of materials, called high-entropy alloys (HEAs). Here, we discuss the serration behaviors of several HEAs from cryogenic to elevated temperatures. The experimental results of slow compression and tension tests are compared with the predictions of a slip-avalanche model for the deformation of a broad range of solids. The results shed light on the deformation processes in HEAs. Temperature effects on the distributions of stress drops and the decrease of the cutoff (i.e., of the largest observed slip size) for increasing temperature qualitatively agree with the model predictions. The model is used to quantify the serration characteristics of HEAs, and pertinent implications are discussed.