Effect of Particles on the Mechanical Behaviour of CoCrFeNiAl_(0.3) High-Entropy Alloy Single Crystals

摘要

The effect of y'-phase particles on the mechanical behaviour was studied in single crystals of the fcc CoCrFeNiAl_(0.3) (at %) high-entropy alloy (HEA) under tensile strain. It was shown that ageing of the CoCrFeNiAl_(0 3) HEA single crystals at a temperature of 823 K for 150 hours and at 893 K for 50 hours, results in the precipitation of y'-phase particles of size d< 5 nm, with Ll_2-type ordering. In the [111] -oriented crystals, precipitation of y'-phase particles leads to an increase in critical shear stresses τ_(cr) by 25-30 MPa in the temperature range T= 77-873 K, a decrease in the strain hardening coefficient Θ = da/dε and an increase in plasticity of 11-14% relative to the initial crystals without particles. The decrease in Θ = dσ/dε and the increase in plasticity are associated with the influence of the y'-phase particles on the localization of the deformation, predominantly in one system.