Structure and hardness of in situ synthesized nano-oxide strengthened CoCrFeNi high entropy alloy thin films

TL;DR

This paper investigates the formation of nano-oxide particles within CoCrFeNi high-entropy alloy thin films, demonstrating that these particles significantly enhance hardness through internal oxidation and Orowan strengthening.

Contribution

It introduces a novel method for synthesizing nano-oxide strengthened high-entropy alloy thin films with improved mechanical properties.

Findings

Nano-oxide particles identified as Cr2O3

Hardness increased by 14% due to oxide particles

Internal oxidation enables oxide dispersion in the alloy

Abstract

In this study, we report on face-centered cubic structured CoCrFeNi high-entropy alloy thin films with finely dispersed nano-oxide particles which are formed by internal oxidation. Analytical scanning transmission electron microscopy imaging found that the particles are Cr2O3. The oxide particles contribute to the hardening of the film increasing its hardness by 14% compared to that of the film without precipitates, through the Orowan-type strengthening mechanism. Our novel approach paves the way to design medium- and high-entropy alloys with high strength by making use of oxide phases.