Microstructures and properties of CoCrCuFeNiMox high-entropy alloys fabricated by mechanical alloying and spark plasma sintering

ABSTRACT

CoCrCuFeNiMox (x values in molar ratio, x = 0, 0.2, 0.4 and 0.8) high-entropy alloys were prepared by mechanical alloying and spark plasma sintering method. The effects of Mo addition on microstructure and mechanical properties were investigated. The X-ray diffraction (XRD) result showed that the addition of Mo into CoCrCuFeNi high-entropy alloy (HEA) changed the original phase constitution from FCC to FCC + σ + μ and the peak intensity of (1 1 1) shifted to the left and decreased steadily. The field emission scanning electron microscope confirmed that the Cu-rich second FCC phase disappeared and the σ phase with a tetragonal structure expanded as the Mo content was increased. Additionally, a high density of dimple-like features were seen in CoCrCuFeNi HEA while typical quasi-cleavage facets could be observed from the fracture surfaces of the HEAs with the addition of Mo. The Mo0.8 alloy showed a good wear resistant and appropriate strength with fracture strain 22.70%, fraction coefficient 0.65, hardness 530 HV and compressive strength 1448 MPa.

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 alloys
• Mo
• mechanical alloying
• mechanical properties
• microstructure

Acknowledgements

The authors are grateful for financial support from the Scientific Research Foundation of Jiangxi University of Science and Technology (jxxjbs17009).

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Qiumin Yang was born on December 27th, 1986 in Hunan/China. He studied materials science and technology at the Central South University from 2009 to 2016. In 2016, he finished his PhD at the State Key Laboratory of Powder Metallurgy of the Central South University. Now, he worked as a research engineer at the Jiangxi University of Science and Technology.

Yanyuan Tang was born on December 29th, 1985 in Jiangxi/China. He studied materials science and technology at the Jiangxi University of Science and Technology from 2013 to 2018. Since 2016, he worked as a material engineer at Chongyi Zhangyuan Tungsten Co., Ltd.

Yan Wen was born on October 4th, 1992 in Jiangxi/China. In 2012, He entered Jiangxi University of Science and Technology and graduated in 2016 with a bachelor's degree in materials science and technology. Now, he is studying for a master's degree at Jiangxi University of Science and Technology from 2016.

Qinying Zhang was born on December 13th, 1994 in Jiangxi/China. In 2012, He entered Jiangxi University of Science and Technology and graduated in 2016 with a bachelor's degree in materials science and technology. Now, he is studying for a master's degree at Jiangxi University of Science and Technology from 2016.

Dengfei Deng was born on June 19th, 1985 in Jiangxi/China. In 2005, He entered Jiangxi University of Science and Technology and graduated in 2009 with a bachelor's degree in materials science and technology. In 2012, he finished his master's degree. Since then he has been working as a material engineer at Chongyi Zhangyuan Tungsten Co., Ltd.

Xinren Nai was born on July 16th, 1987 in Jiangxi/China. In 2007, He entered Jiangxi University of Science and Technology and graduated in 2011 with a bachelor's degree in materials science and technology. In 2014, he finished his master's degree. Since then he has been working as a material engineer at Chongyi Zhangyuan Tungsten Co., Ltd.