Corrosion resistant and tough multi-principal element Cr-Co-Ni alloys

Date

2021

Authors

Koga, Guilherme Yuuki
Birbilis, Nick
Zepon, Guilherme
Kiminami, Claudio Shyinti
Botta, Walter Jose
Kaufman, Michael
Clarke, Amy
Coury, Francisco Gil

Journal Title

Journal ISSN

Volume Title

Publisher

Elsevier

Abstract

Cr-Co-Ni Multi-Principal Element Alloys (MPEAs) with good combinations of strength and ductility were studied to determine their attendant corrosion performance. Three alloys – Cr45Co27.5Ni27.5, Cr33.3Co33.3Ni33.3, and Cr25Co37.5Ni37.5 – were produced in recrystallized and cold-worked states, and their electrochemical response was tested in a simulated seawater electrolyte. Increasing the Cr content improved the yield strength (σy) and ultimate tensile strength (UTS), while maintaining high (>40%) uniform elongation. Potentiodynamic polarization and electrochemical impedance spectroscopy revealed high corrosion resistance of the alloys in simulated seawater, in particular the Cr-rich alloy (Cr45Co27.5Ni27.5). Furthermore, following 40% cold work, the Cr45Co27.5Ni27.5 alloy displayed a further improvement in corrosion resistance. The Cr45Co27.5Ni27.5 alloy displays mechanical and corrosion properties that exceed those of conventional structural alloys such as Ni-superalloys, stainless steels and most 3d-transition metal MPEAs, including those without appreciable ductility. Therefore, in the present work it is shown that increasing the Cr content in Cr-Co-Ni alloys leads to a better combination of mechanical properties and corrosion resistance in saline environment, as observed especially for the Cr45Co27.5Ni27.5 alloy.

Description

Keywords

High entropy alloys, Compositionally complex alloys, Multi-principal element alloys, Corrosion, Toughness, Marine

Citation

Source

Journal of Alloys and Compounds

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

Restricted until

2099-12-31
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