J. Mater. Sci. Technol. ›› 2023, Vol. 158: 218-225.DOI: 10.1016/j.jmst.2023.01.042

• Research article • Previous Articles     Next Articles

Nanoscale fluctuation of stacking fault energy strengthens multi-principal element alloys

Zongrui Peia,b,*, Markus Eisenbachb, Peter K. Liawc, Mingwei Chend,e   

  1. aNew York University, New York 10012, USA;
    bOak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA;
    cDepartment of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996, USA;
    dDepartment of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA;
    eEngineering and Hopkins Extreme Materials Institute, Johns Hopkins
  • Received:2022-11-25 Revised:2023-01-07 Accepted:2023-01-12 Published:2023-09-20 Online:2023-09-15
  • Contact: *E-mail address:peizongrui@gmail.com , zp2137@nyu.edu (Z. Pei)

Abstract: Chemical randomness and the associated energy fluctuation are essential features of multi-principal element alloys (MPEAs). Due to these features, nanoscale stacking fault energy (SFE) fluctuation is a natural and independent contribution to strengthening MPEAs. However, existing models for conventional alloys (i.e., alloys with one principal element) cannot be applied to MPEAs. The extreme values of SFEs required by such models are unknown for MPEAs, which need to calculate the nanoscale volume relevant to the SFE fluctuation. In the present work, we developed an analytic model to evaluate the strengthening effect through the SFE fluctuation, profuse in MPEAs. The model has no adjustable parameters, and all parameters can be determined from experiments and ab initio calculations. This model explains available experimental observations and provides insightful guidance for designing new MPEAs based on the SFE fluctuation. It generally applies to MPEAs in random states and with chemical short-range order.

Key words: Nanoscale energy fluctuation, Staking fault energy, Chemical short-range order, Multi-principal element alloy, Mechanism