Abstract
Two important and desirable properties of materials for most structural applications are high tensile strength and ductility, which typically require high work hardening to delay necking. Here, we designed and tensile tested a face-centered cubic (fcc) Fe-Cr-Co-Ni medium-entropy alloy in which multiple deformation mechanisms are triggered during tensile loading at different temperatures to induce sustained work hardening. Our strategy involved control of the relative stabilities of the fcc, hcp (hexagonal close-packed), and bcc (body-centered cubic) phases in this quaternary system via high-throughput thermodynamic calculations. This alloy not only exhibits extensive deformation-induced nanotwinning at room temperature, but also displays a two-step sequential phase transformation [γ (fcc) → ε (hcp) martensite → α’ (bcc) martensite] at 77 K, which contrasts with the single-step phase transformation [γ → ε martensite] observed in many other fcc high/medium entropy alloys with a low stacking fault energy. The sequence of phase transformation at 77K was supported by first-principles density functional theory calculations. This work provides new templates for the design of alloys capable of multiple deformation mechanisms for sustained work hardening.
| Original language | English |
|---|---|
| Article number | 103663 |
| Journal | International Journal of Plasticity |
| Volume | 167 |
| DOIs | |
| State | Published - Aug 2023 |
Funding
This work was sponsored by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. This research used the Talos F200X S/TEM tool provided by US DOE NE, Fuel Cycle R&D Program and the Nuclear Science User Facilities. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Work by S.H. and H.X. was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award No. DE-SC0019151. JLC was supported by the Governor's Chair program at the University of Tennessee. Ian Stinson in Material Science and Technology Division at ORNL was acknowledged for performing tensile tests in this work. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). This work was sponsored by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. This research used the Talos F200X S/TEM tool provided by US DOE NE, Fuel Cycle R&D Program and the Nuclear Science User Facilities. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Work by S.H. and H.X. was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences , under Award No. DE-SC0019151 . JLC was supported by the Governor's Chair program at the University of Tennessee. Ian Stinson in Material Science and Technology Division at ORNL was acknowledged for performing tensile tests in this work.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | |
| Oak Ridge National Laboratory | |
| University of Tennessee | |
| Division of Materials Sciences and Engineering | DE-SC0019151 |
Keywords
- High/medium entropy alloy
- Nano-twinning
- Plasticity
- Sequential phase transformation
- Work hardening