Mechanical and thermal expansion behaviour of TiC-reinforced CoCrFeMnNi high entropy alloy prepared by mechanical alloying and spark plasma sintering

ABSTRACT

In this study, TiC-reinforced CoCrFeMnNi high-entropy alloy (HEA) composites were prepared by mechanical alloying (MA) and spark plasma sintering (SPS). The phase composition, microstructure, mechanical and thermal expansion behaviour of composite HEAs were investigated. The results reveal that the addition of TiC has no effect on the crystal structure, however, the microstructure and mechanical properties show a strong dependency on the TiC content. Compared to the original HEA, the composite HEA shows decreased grain size, resulting in TiC nanoparticles (NPs) retarding grain growth by pinning the grain boundaries. With increasing TiC content from 0 to 4 wt-%, significant increases in the hardness from 410 to 480 HV and compressive yield strength from 680 to 1100 MPa, which is mainly due to the grain boundary and dispersion strengthening effects. Moreover, the thermal expansion curves show linear increments up to 800°C and decrease with increasing TiC content.

KEYWORDS:

• High-entropy alloys
• powder metallurgy
• microstructure
• mechanical properties
• thermal expansion coefficient

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.

Additional information

Funding

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government (MSIT) (No. 2021R1A2C1005478). This research was also supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2022R1I1A1A01055105).