Title

High entropy alloy FeMnNiCoCr coatings: Enhanced hardness and damage-tolerance through a dual-phase structure and nanotwins

Document Type

Journal Article

Publication Title

Surface and Coatings Technology

Publisher

Elsevier

School

School of Engineering

Comments

Sha, C., Zhou, Z., Xie, Z., & Munroe, P. (2020). High entropy alloy FeMnNiCoCr coatings: Enhanced hardness and damage-tolerance through a dual-phase structure and nanotwins. Surface and Coatings Technology, 385, Article 125435. https://doi.org/10.1016/j.surfcoat.2020.125435

Abstract

Three FeMnNiCoCr high entropy alloy (HEA) coatings were deposited onto M2 steel substrates using a direct current (DC) magnetron sputtering system under a range of substrate bias voltages (−20 V, −60 V and −120 V). The microstructure transformed from a fine elongated structure to coarse V-shaped columnar grains with increasing substrate bias voltage. A high density of nanotwins, together with the presence of a partial fcc-to-hcp transformation, was observed in the coating deposited at −120 V. This was attributed to the introduction of stacking faults whose presence was promoted by preferential re-sputtering effects during the deposition process. A high hardness value of ~9.1 GPa, accompanied by exceptional damage-tolerance, was achieved in the coating deposited at −120 V. Here, the formation of nanotwins and the dual-phase structure was found to contribute to this remarkable combination of hardness and resistance to plastic deformation.

DOI

10.1016/j.surfcoat.2020.125435

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