Title: Microstructure and mechanical properties of bulk annealed AlCoCrFeNi_2.1 eutectic high-entropy alloy

Authors: Wenna Jiao; Junyang He; Tianxin Li; Yiping Lu; Tingju Li

Addresses: Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024, China ' State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083, China ' Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024, China ' Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024, China ' Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024, China

Abstract: Eutectic high-entropy alloys (EHEAs) with excellent casting and mechanical properties are promising candidates for the industrial application. In this paper, the phase and microstructure stability of bulk AlCoCrFeNi_2.1 EHEA at 2.5 kg level in as-cast and 900°C, 1000°C and 1100°C annealed states were investigated. Uniform lamellar structure composed of face centred cubic (FCC) and B2 phase prevails in the as-cast alloy, and maintains stable up to 1100°C. Rod-like precipitates appear in FCC phase after the heat treatment of 900 °C, and the irregular lamellar structure seems coarser. Moreover, the hardness of the EHEA falls into a narrow range of 245 HV to 278 HV regardless of the change of the annealing temperature. The tensile test results further confirm that the AlCoCrFeNi_2.1 EHEA maintains good mechanical properties.

Keywords: eutectic high entropy alloy; AlCoCrFeNi_2.1; stability; microstructure; hardness; mechanical properties; precipitates; Lamellar spacing; as-cast; as-annealed.

DOI: 10.1504/IJCMSSE.2021.118495

International Journal of Computational Materials Science and Surface Engineering, 2021 Vol.10 No.2, pp.57 - 68

Received: 19 Sep 2020
Accepted: 17 Feb 2021
Published online: 27 Oct 2021 *

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