In this work, molecular dynamics was used to investigate the effect of grain size and temperature on the elastic constants and hardness of CoCrFeMnNi high entropy alloy through atomistic simulations. Grain sizes of up to 4 nm to 20 nm were simulated, across a temperature range of 100 to 1000 Kelvin.
The systems were equilibrated using a conjugate gradient style minimization followed by an NpT ensemble. Elastic constants were calculated using the deformation method, and for polycrystalline systems, averaged using Hill’s averaging method. When available, the results proved to be well in agreement with experiment and other atomistic simulations. The elastic constants were found to increase with grain size on this scale.
In addition to the elastic response, the plastic response was quantified by calculating the hardness through nanoindentation. The grain size effects on flow stress were examined, and this work shows an inverse Hall-Petch relationship for the Cantor alloy.