Molecular dynamics study on the dislocation evolution mechanism of temperature effect in nano indentation of FeCoCrCuNi high-entropy alloy

ABSTRACT

In this paper, the atomic model of high-entropy alloy is established by molecular dynamics simulation. By applying nano-indentation, the influence of Cu atomic ratio and temperature on the deformation of FeCoCrCuNi high-entropy alloy was studied, and the micro-scale dislocation movement evolution mechanism was obtained. The results show that, with the increase of temperature, the load of FeCoCrCuNi high-entropy alloy under nano indentation decreases. The total length of dislocations in each stage of nanoindentation decreases monotonically, and the types of dislocation reactions decrease. Under the action of high temperature, the number of perfect dislocations decomposed into Shockley partial dislocations decreases, resulting in more Frank dislocations and Stair-rod dislocations, which makes the extended dislocations recombine into perfect dislocations, and the length of dislocations decreases sharply. The dislocation defect is replaced by a cavity at high temperature, which makes the high-entropy alloy lose elastoplastic mechanical properties.

KEYWORDS:

• Molecular dynamics
• high entropy alloy
• dislocation motion
• nanoindentation

Acknowledgments

We acknowledge the guidance given by Key Laboratory of Science and Technology on Materials under Shock and Impact.

Disclosure statement

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

Author contribution statement

Ye Du – Primary author and performed most of the simulation and analysis in this manuscript.

Qiang Li – Collected data and provided proofreading the manuscript.

Data availability statement

The raw/processed data required to reproduce these findings cannot be shared at this time due to legal and ethical reasons.

Additional information

Funding

This paper is supported by the Opening Project of State Key Laboratory of Explosion Science and Technology [Beijing Institute of Technology, grant number KFJJ22-06 M]; Funded by Shanxi Basic Research Program [grant number 20210302124196, 202203021211097]; Funded by Foundation Strengthening Plan Technology Field Fund [grant number 2021-JCJQ-JJ-1195].