Work

Phase structure, microstructure, and mechanical properties of FeCoCrNi-based eutectic high-entropy alloys reinforced with MWCNTs and Gr

Year: 2025

Type: article

Abstract: This study primarily focuses on the phase structure, microstructure, and mechanical behaviour of Fe 25 Co 25 Cr 25 Ni 25 equiatomic EHEAs upon adding 2 wt% of Multi-Walled Carbon Nanotubes (MWCNTs) and Graphene (Gr) as reinforcements. The alloying processes include Mechanical Alloying (MA) and Vacuum Arc Melting (VAM). The as-milled MA powder is irregularly shaped, with an average particle size of 23.5 μm. Samples subjected to MA followed by VAM exhibited a single-phase alloy composition , with a near-equal chemical distribution of major Face-Centered Cubic (FCC) and minor Body-Centered Cubic (BCC) crystal structures, as confirmed by X-ray diffraction (XRD) analysis. The Vickers microhardness values of the Fe 25 Co 25 Cr 25 Ni 25 EHEAs samples were 123 ± 7 HV, while the additions of MWCNTs and Gr increased the hardness to 146 ± 6 HV and 155 ± 9 HV, respectively. To further enhance the strengthening behaviour, the EHEAs samples were heat-treated in a Nabertherm furnace at 1100 °C under an argon atmosphere, resulting in hardness values of 134 ± 6 HV, 164 ± 8 HV, and 171 ± 7 HV for the base alloy , MWCNTs addition, and Gr addition. Adding MWCNTs and Gr enhances the thermal stability of the as-milled powder, preventing secondary phase formation and improving the alloy stability of the equiatomic Fe 25 Co 25 Cr 25 Ni 25 composition. Specifically, Fe 25 Co 25 Cr 25 Ni 25 exhibited thermal stability up to 534 °C, while Fe 25 Co 25 Cr 25 Ni 25 +MWCNTs achieved 612 °C, and Fe 25 Co 25 Cr 25 Ni 25 +Gr demonstrated thermal stability up to 713 °C, with no mass loss or phase change observed, as revealed by thermogravimetric analysis (TGA). Furthermore, adding 2 wt% graphene resulted in superior hardness, residual compressive stress , and thermal stability compared to the MWCNTs addition.

Source: Journal of Science Advanced Materials and Devices

DOI: 10.1016/j.jsamd.2025.100868

Authors: Balaji V, Arivazhagan A, Anthony Xavior M

Institutions: Vellore Institute of Technology University, Coventry University

Language: English

Topic: High Entropy Alloys Studies

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,300

Funders: British Council, UK-India Education and Research Initiative, Scheme for Promotion of Academic and Research Collaboration