Sintering mechanism of CoCrFeMnNi high-entropy alloy powders

ABSTRACT

High-entropy alloys (HEAs) have emerged as a new alloy system, with many attractive properties. Among the fabrication routes, mechanical alloying followed by sintering, have been widely used. However, sintering mechanisms of HEA powders have not yet been fully understood. This work attempts to understand the sintering kinetics of CoCrFeNiMn HEA powders. A comparative study has been done on CoCrFeNiMn alloy powders on as-milled and annealed conditions, which revealed different sintering behaviours. Decreasing densification rates with increasing activation energies were observed through dilatometry after the annealing treatment. Combined diffusion coefficients and activation energies analysed through the sintering models indicate that during sintering of the as-milled powder, mass transport occurred through several modes. On the other hand, the annealed CoCrFeNiMn alloy powder (which was nearly single phase) clearly reveals volume diffusion as the controlling mechanism during sintering. It was characterised with large activation energy.

Special theme block on high entropy alloys, guest edited by Paula Alvaredo Olmos, Universidad Carlos III de Madrid, Spain, and Sheng Guo, Chalmers University, Gothenburg, Sweden.

KEYWORDS:

• High-entropy alloy
• mechanical alloying
• dilatometer
• sintering
• diffusion

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Erratum

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Rahul B. Mane is a PhD research scholar in the Department of Materials Science and Metallurgical Engineering, Indian Institute of Technology Hyderabad.

Rajkumar Y. received PhD from the Department of Materials Science and Metallurgical Engineering, Indian Institute of Technology Hyderabad.

Bharat B. Panigrahi is an Associate Professor and Head of The Department of Materials Science and Metallurgical Engineering, Indian Institute of Technology Hyderabad.