J. Mater. Sci. Technol. ›› 2020, Vol. 39: 1-6.DOI: 10.1016/j.jmst.2019.09.010

• Letter •     Next Articles

Effect of grain size on fatigue cracking at twin boundaries in a CoCrFeMnNi high-entropy alloy

A.G. Wanga, X.H. Ana*(), J. Gub, X.G. Wangc, L.L. Licd, W.L. Lia, M. Songb*(), Q.Q. Duanc, Z.F. Zhangc, X.Z. Liaoa*()   

  1. a School of Aerospace, Mechanical & Mechatronic Engineering, The University of Sydne0y, Sydney, Australia
    b State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China
    c Materials Fatigue and Fracture Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
    d Max-Planck-Institut für Eisenforschung, Max-Planck-Straße 1, 40237 Düsseldorf, Germany
  • Received:2019-06-14 Revised:2019-08-30 Accepted:2019-09-02 Published:2020-02-15 Online:2020-03-11
  • Contact: An X.H.,Song M.,Liao X.Z.

Abstract:

The fatigue cracking behavior at twin boundaries (TBs) in a CoCrFeMnNi high-entropy alloy with three different grain sizes was systematically investigated under low-cycle fatigue. Irrespective of grain size, the change from slip band cracking to TB cracking occurred with increasing the difference in the Schmid factors (DSF) between matrix and twin. However, the required critical DSF for the transition of the dominant cracking mode decreases with decreasing grain size due to the reduced slip band spacing that increases the impingement sites on the TBs and facilitates the coalescence of defects and voids to initiate TB cracks.

Key words: High-entropy alloy, Fatigue cracking, Twin boundary, Slip band, Grain size