J. Mater. Sci. Technol. ›› 2021, Vol. 72: 52-60.DOI: 10.1016/j.jmst.2020.09.021

• Research Article • Previous Articles     Next Articles

Elemental partitioning as a route to design precipitation-hardened high entropy alloys

Feng Hea,b, Bin Hana,c, Zhongsheng Yangb, Da Chena,d, Guma Yelia, Yang Tonge, Daixiu Weif, Junjie Lib, Zhijun Wangb,*(), Jincheng Wangb,*(), Ji-jung Kaia,d,**()   

  1. a Centre for Advanced Nuclear Safety and Sustainable Development, City University of Hong Kong, Hong Kong, China
    b State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, 710072, China
    c Institute of Atomic and Molecular Science, Shaanxi University of Science and Technology, Xi’an, 710021, China
    d Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China
    e Division of Materials Science and Technology, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
    f Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai, Miyagi, 980-8577, Japan
  • Received:2020-07-29 Revised:2020-09-10 Accepted:2020-09-12 Published:2021-05-10 Online:2021-05-10
  • Contact: Zhijun Wang,Jincheng Wang,Ji-jung Kai
  • About author:** Centre for Advanced Nuclear Safety and SustainableDevelopment, City University of Hong Kong, Hong Kong, China. E-mail addresses: jijkai@cityu.edu.hk (J.-j. Kai).
    jchwang@nwpu.edu.cn (J. Wang),
    * E-mail addresses: zhjwang@nwpu.edu.cn (Z. Wang),

Abstract:

Precipitation-hardened high entropy alloys (HEAs) with carefully tuned compositions have shown excellent mechanical properties, demonstrating great potential for engineering applications. However, due to the lack of precise multiple phase diagrams, the composition design of multi-principal-component HEAs still inevitably relies on the extremely time-consuming trial-and-error approach. The present study, on the basis of powerful composition quantification ability of atom probe tomography (APT) technology, proposed a framework to guide the quantitative design of precipitation-hardened HEAs. In this framework, the elemental partitioning was used as a crucial route to avoid the thermodynamic challenge of designing precipitation-hardened HEAs. As a case study, the role of Ti/Al ratio in the design of γ-γ′ HEAs was predicted through the proposed framework and then validated by experimental studies. The framework predicted that when the total content of Ti and Al is fixed, a higher Ti/Al ratio makes γ-γ′ HEA stronger. APT and mechanical results agreed well with these predictions and validated the feasibility of the framework. These findings provided a new route to design the precipitation-hardened alloys and a deeper insight into the design of γ-γ′ HEA.

Key words: Elemental partitioning, Alloy design, Atom probe tomography, High entropy alloys