Vacancy formation enthalpies of high-entropy FeCoCrNi alloy via first-principles calculations and possible implications to its superior radiation tolerance

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Author(s)

  • Weiliang Chen
  • Xueyong Ding
  • Yuchao Feng
  • Xiongjun Liu
  • Kui Liu
  • Z.P. Lu
  • Dianzhong Li
  • Yiyi Li
  • Xing-Qiu Chen

Detail(s)

Original languageEnglish
Pages (from-to)355-364
Journal / PublicationJournal of Materials Science and Technology
Volume34
Issue number2
Online published2 Nov 2017
Publication statusPublished - Feb 2018

Abstract

Because atoms in high-entropy alloys (HEAs) coordinate in very different and distorted local environments in the lattice sites, even for the same type of constituent, their point defects could highly vary. Therefore, theoretical determination of the thermodynamic quantities (i.e., defect formation enthalpies) of various point defects is rather challenging because each corresponding thermodynamic quantity of all involve constituents is not unique. The knowledge of these thermodynamic quantities is prerequisite for designing novel HEAs and understanding the mechanical and physical behaviors of HEAs. However, to date there has not been a good method to theoretically derive the defect formation enthalpies of HEAs. Here, using first-principles calculations within the density functional theory (DFT) in combination of special quasi-random structure models (SQSs), we have developed a general method to derive corresponding formation enthalpies of point defects in HEAs, using vacancy formation enthalpies of a four-component equiatomic fcc-type FeCoCrNi HEA as prototypical and benchmark examples. In difference from traditional ordered alloys, the vacancy formation enthalpies of FeCoCrNi HEA vary in a highly wide range from 0.72 to 2.89 eV for Fe, 0.88–2.90 eV for Co, 0.78–3.09 eV for Cr, and 0.91–2.95 eV for Ni due to high-level site-to-site lattice distortions and compositional complexities. On average, the vacancy formation enthalpies of 1.58 eV for Fe, 1.61 eV for Cr, 1.70 eV for Co and 1.89 eV for Ni are all larger than that (1.41 eV) of pure fcc nickel. This fact implies that the vacancies are much more difficult to be created than in nickel, indicating a reasonable agreement with the recent experimental observation that FeCoCrNi exhibits two orders of amplitudes enhancement of radiation tolerance with the suppression of void formation at elevated temperatures than in pure nickel.

Research Area(s)

  • FeCoCrNi, First-principles calculations, Modeling high-entropy alloys, Point defects, Vacancy formation enthalpy

Citation Format(s)

Vacancy formation enthalpies of high-entropy FeCoCrNi alloy via first-principles calculations and possible implications to its superior radiation tolerance. / Chen, Weiliang; Ding, Xueyong; Feng, Yuchao; Liu, Xiongjun; Liu, Kui; Lu, Z.P.; Li, Dianzhong; Li, Yiyi; Liu, C.T.; Chen, Xing-Qiu.

In: Journal of Materials Science and Technology, Vol. 34, No. 2, 02.2018, p. 355-364.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal