Page 7 - MSAM-2-1

Materials Science in

Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Microstructure, mechanical properties,

and corrosion performance of additively
manufactured CoCrFeMnNi high-entropy alloy

before and after heat treatment

Roman Savinov, Jing Shi*
Department of Mechanical and Materials Engineering, College of Engineering and Applied Science,
University of Cincinnati, Cincinnati, OH 45221, USA

Abstract

Equiatomic CoCrFeMnNi, one of the well-known high-entropy alloys, possesses
attractive mechanical properties for many potential applications. In this research, the
effects of heat treatment on additively manufactured CoCrFeMnNi materials were
studied. A pilot experiment was conducted to select two selective laser melting
(SLM) conditions of different laser scanning speeds based on the density and
porosity of obtained materials. Thereafter, microstructure, tensile properties, impact
fracture, microhardness, and corrosion resistance were investigated for the materials
obtained under the two selected SLM conditions, with and without heat treatment. It
was discovered that while the texture with a strong <100> alignment was observed
in both as-built and heat treated materials, the texture of heat treated materials
*Corresponding author: was stronger. Also, heat treatment drastically improved the ductility of as-built
Jing Shi CoCrFeMnNi by 23 – 59% for the selected SLM conditions, while the ultimate tensile
(jing.shi@uc.edu) strength showed only negligible change. The increase of ductility was believed to
Citation: Savinov R, Shi J, 2023, result from the release of residual strain and the increase of average grain size after
Microstructure, mechanical properties, heat treatment. Moreover, heat treatment was able to bring noticeable improvement
and corrosion performance of
additively manufactured CoCrFeMnNi in energy absorption for the as-built CoCrFeMnNi, reflected by 11 – 16% more energy
high-entropy alloy before and after absorption. Besides, all studied materials showed signs of ductile fracture, but more
heat treatment. Mater Sci Add Manuf, signs of brittle fracture, such as cleavage facets, were found in the as-built materials
2(1): 42.
https://doi.org/10.36922/msam.42 as compared with the heat-treated materials. In addition, higher laser scan speed was
found to cause moderate reduction in corrosion resistance. Effect of heat treatment
Received: November 9, 2022
was also negative and mild for lower scanning speed case. However, the highest
Accepted: December 28, 2022 reduction in corrosion resistance was observed after heat treatment of the high laser
Published Online: February 9, 2023 scanning speed case.
Copyright: © 2023 Author(s).
This is an Open Access article Keywords: CoCrFeMnNi; High-entropy alloy; Additive manufacturing; Selective laser
distributed under the terms of the
Creative Commons Attribution melting; Properties; Microstructure
License, permitting distribution,
and reproduction in any medium,
provided the original work is
properly cited. 1. Introduction
Publisher’s Note: AccScience
Publishing remains neutral with Until recently, the main strategy used in material engineering to produce alloys was
regard to jurisdictional claims in
published maps and institutional choosing a principal element and adding several secondary elements to it. Such principal
[1]
affiliations. element approach considerably limits the scope of alloy development . Common

Volume 2 Issue 1 (2023) 1 https://doi.org/10.36922/msam.42