Stress State, Strain Rate and Temperature Sensitivity of Alx(CrCoFeNi)1-x High Entropy Alloys (HEAs)

High Entropy Alloys (HEAs) are equiatomic, multicomponent metallic systems, that presents exceptional microstructural stability. Recently, HEAs have been proposed aspotential replacements for existing high temperature structural materials and coatings dueto their reportedly favorable combinations of high melting point, high strength, highductility, and high resistance to oxidation and/or corrosion. Although the potential applications of HEAs are promising, knowledge of their mechanical performance under extreme deformation conditions are not well understood. This work focuses on the study of the stress-state, strain rate and temperature effects on the plastic flow and deformed microstructural features of a series of Al0.3-0.7at.%(CrCoFeNi)1-x HEAs. The culminations of experimental results are intended to be the fundamental building blocks necessary to develop accurate constitutive material models. Interestingly, X-ray Diffraction (XRD) identified that the Al0.7 HEA consisted of a multi-phase BCC and FCC microstructure that exhibited a linear hardening at both quasi-static (10-3/s) and high strain rate (2000/s).While the Al0.3 HEA exhibited a FCC microstructure according to XRD analysis with sigmoidal plastic behavior suggesting multiple deformation mechanisms occurring in the material when loaded at both quasi-static (10-3/s) and high strain rate (2000/s).