The constitutive model and threshold stress for characterizing the deformation mechanism of Al_0.3CoCrFeNi high entropy alloy

Isothermal compression experiment of Al_0.3CoCrFeNi high entropy alloy were performed at high temperatures. The effects of temperature and strain rate on the deformation behavior are investigated. A constitutive model incorporates the effects of strain rate, strain and temperature is developed to describe the flow stress. Experimental analysis show that the stress exponent n is generally greater than five, which decreases rapidly with increasing of temperature at the initial stage and changes slower subsequently. Structure characterization by the transmission electron microscopy demonstrates that dislocation–precipitate interaction exists during high temperature deformation and the precipitate is B₂-type NiAl phase.