Effect of Zr content on microstructure and mechanical properties of lightweight Al2NbTi3V2Zrx high entropy alloy

Qian Zhi; Xinrong Tan; Zhongxia Liu; Yang Liu; Qiong Zhang; Yuqiang Chen; Maohua Li

doi:10.1016/j.micron.2021.103031

Effect of Zr content on microstructure and mechanical properties of lightweight Al₂NbTi₃V₂Zr_x high entropy alloy

Micron. 2021 May:144:103031. doi: 10.1016/j.micron.2021.103031. Epub 2021 Feb 10.

Authors

Qian Zhi¹, Xinrong Tan², Zhongxia Liu³, Yang Liu¹, Qiong Zhang⁴, Yuqiang Chen¹, Maohua Li¹

Affiliations

¹ Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion, Hunan Provincial Key Defense Laboratory of High Temperature Wear-resisting Materials and Preparation Technology, School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China.
² Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion, Hunan Provincial Key Defense Laboratory of High Temperature Wear-resisting Materials and Preparation Technology, School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China; Hunan Vanguard Group CO.LTD, China. Electronic address: tanxinrong0@163.com.
³ School of Physics and Engineering, Zhengzhou University, Zhengzhou, 450052, China. Electronic address: liuzhongxia0@163.com.
⁴ Hunan Vanguard Group CO.LTD, China.

PMID: 33618202
DOI: 10.1016/j.micron.2021.103031

Abstract

Lightweight Al₂NbTi₃V₂Zr_x (x = 1.0, 0.8, 0.6, 0.4, 0.2, 0) high entropy alloys are produced by mechanical milling and vacuum hot pressing. The microstructure, phase evolution and mechanical properties of the alloys are analyzed. The microstructure of the alloys with x = 1.0, 0.8, 0.6 consists of BCC solid solution matrix and two intermetallics (i.e., α and β), and then β phase disappears in Al₂NbTi₃V₂Zr_0.4 alloy. Further decreasing Zr content to below 0.2, α phase vanishes and γ and δ intermetallics emerge in Al₂NbTi₃V₂Zr_0.2 and Al₂NbTi₃V₂ alloys. The Al₂NbTi₃V₂Zr_x alloys cannot obtain a single phase structure by decreasing Zr content with current fabrication process, which is likely because that the mixing entropy of the HEA system is not large enough to prohibit the formation of the secondary phases at hot pressing temperature of 1250 °C. All the bulks possess low density ranging from 4.93 to 5.21 g/cm³. Hardness of the Al₂NbTi₃V₂Zr_x alloys decreases from 781 HV to 697 HV and then increases to 814 HV with the decrease of Zr from x = 1 to 0. This varying tendency is closely related with the content of secondary intermetallic phases. The compressive test shows the Al₂NbTi₃V₂Zr_0.4 alloy has a yield strength of 1742 MPa, fracture strength of 2420 MPa, compressive strain of 38.2 %, which is probably related to its simplest microstructure. The comprehensive mechanical property of Al₂NbTi₃V₂Zr_0.4 alloy is superior to the majority of other HEAs and Ti64 alloy.

Keywords: Comprehensive mechanical properties; Hardness; Lightweight high entropy alloy; Microstructure.