On the onset of deformation twinning in the CrFeMnCoNi high-entropy alloy using a novel tensile specimen geometry

Journal Article · 09 May 2019 · Intermetallics

DOI: https://doi.org/10.1016/j.intermet.2019.04.012 · OSTI ID:1543214

Thurston, Keli V. S. ^[1]; Hohenwarter, Anton ^[2]; Laplanche, Guillaume ^[3]; George, Easo P.  ^[4]; Gludovatz, Bernd ^[5]; Ritchie, Robert O. ^[1]

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1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
2. Austrian Academy of Sciences, Leoben (Austria)
3. Ruhr Univ., Bochum (Germany)
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
5. Univ. of New South Wales, Sydney, NSW (Australia)

Deformation-induced nanoscale twinning is one of the mechanisms responsible for the excellent combination of strength and fracture toughness of the single-phase, face-centered cubic CrMnFeCoNi (Cantor) alloy, especially at cryogenic temperatures. In this work, we use a novel, modified dogbone geometry that allows the sampling of varying stress and strain regions within a single tensile specimen to characterize the onset of twinning in CrMnFeCoNi at 293 K, 198 K and 77 K. Electron backscatter diffraction (EBSD) and backscattered electron (BSE) imaging revealed the presence of deformation nano-twins in regions of the samples that had experienced plastic strains of ~25% at 293 K, ~16% at 198 K, and ~8% at 77 K, which are similar to the threshold strains described by Laplanche et al. (Acta Mater. 118, 2016, 152–163). From these strains we estimate that the critical tensile stress for the onset of twinning in this alloy is on the order of 750 MPa.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; German Research Foundation (DFG)
• Grant/Contract Number: AC05-00OR22725; AC02-05-CH11231
• OSTI ID: 1543214
• Journal Information: Intermetallics, Vol. 110, Issue C; ISSN 0966-9795
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English