Nanoindentation Creep Behavior of an Al0.3CoCrFeNi High-Entropy Alloy

Nanoindentation creep behavior was studied on a coarse-grained Al0.3CoCrFeNi high-entropy alloy with a single face-centered cubic structure. The effects of the indentation size and loading rate on creep behavior were investigated. The experimental results show that the hardness, creep depth, creep strain rate, and stress exponent are all dependent on the holding load and loading rate. The creep behavior shows a remarkable indentation size effect at different maximum indentation loads. The dominant creep mechanism is dislocation creep at high indentation loads and self-diffusion at low indentation loads. An obvious loading rate sensitivity of creep behavior is found under different loading rates for the alloy. A high loading rate can lead to a high strain gradient, and numerous dislocations emerge and entangle together. Then during the holding time, a large creep deformation characteristic with a high stress exponent will happen.