Microstructural evolution and grain-growth kinetics of Al_0.2CoCrFeNi high-entropy alloy

ABSTRACT

Grain-growth kinetics of high-entropy, single-phase, face-centred cubic (FCC) Al_0.2CoCrFeNi alloy was studied by isothermal annealing over a wide temperature range for different time intervals. Both optical and EBSD studies show a significant amount of annealing twins. Data were analysed using classical grain-growth models and the activation energy was estimated using the Arrhenius type equation. The grain-growth exponent was found to be n = 3 and the measured activation energy for grain growth was 190 ± 15 kJ mol⁻¹. Significant resistance to grain growth was observed at 1100°C. Microstructural characterisation tools like EBSD, along with nanoindentation, was used to understand the observed behaviour.

KEYWORDS:

• High-entropy alloy
• Grain growth
• Annealing twins
• Nanoindentation

Acknowledgments

The authors would like to acknowledge the financial support of DST-FIST programme (Grant no. SR/FST/ETI-421/ 2016) and JICA for funding instrumentation (FESEM-EBSD and Nano-indentation) facilities and Mr. Sairam Goud Kotla for the help in performing nanoindentation experiments. The authors would also like to thank the financial support of MHRD and SERB (grant number ECR/2017/001278).

Disclosure statement

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

Additional information

Funding

This work was supported by Japan International Cooperation Agency; DST-FIST [Grant no. SR/FST/ETI-421/2016]; ECR-SERB: [grant number ECR/2017/001278].