Abstract
The exceptional mechanical strength of medium/high-entropy alloys has been attributed to hardening in random solid solutions. Here, we evidence non-random chemical mixing in a CrCoNi alloy, resulting from short-range ordering. A data-mining approach of electron nanodiffraction enabled the study, which is assisted by neutron scattering, atom probe tomography, and diffraction simulation using first-principles theory models. Two samples, one homogenized and one heat-treated, are observed. In both samples, results reveal two types of short-range-order inside nanoclusters that minimize the Cr–Cr nearest neighbors (L12) or segregate Cr on alternating close-packed planes (L11). The L11 is predominant in the homogenized sample, while the L12 formation is promoted by heat-treatment, with the latter being accompanied by a dramatic change in dislocation-slip behavior. These findings uncover short-range order and the resulted chemical heterogeneities behind the mechanical strength in CrCoNi, providing general opportunities for atomistic-structure study in concentrated alloys for the design of strong and ductile materials.
| Original language | English |
|---|---|
| Article number | 6651 |
| Journal | Nature Communications |
| Volume | 13 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2022 |
Funding
H.W.H. and J.M.Z. are supported by Intel, a SRI grant from GCOE UIUC and NSF DMR-1828671. R.F. thanks for the support from the Materials and Engineering Initiative at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory (ORNL). P.K.L. is supported by the National Science Foundation (DMR-1611180 and 1809640) and the US Army Research Office (W911NF-13–1-0438 and W911NF-19–2-0049). A portion of this research used resources at the High Flux Isotope Reactor (HFIR) and SNS, a U.S. Department of Energy (DOE) Office of Science User Facility operated by the ORNL. APT research was supported by the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. The authors would like to thank Dr. Ken Littrell and Dr. Dunji Yu for their help in neutron-scattering measurements. The authors also thank James Burns for his assistance in performing APT sample prep and experiments. 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 ). H.W.H. and J.M.Z. are supported by Intel, a SRI grant from GCOE UIUC and NSF DMR-1828671. R.F. thanks for the support from the Materials and Engineering Initiative at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory (ORNL). P.K.L. is supported by the National Science Foundation (DMR-1611180 and 1809640) and the US Army Research Office (W911NF-13–1-0438 and W911NF-19–2-0049). A portion of this research used resources at the High Flux Isotope Reactor (HFIR) and SNS, a U.S. Department of Energy (DOE) Office of Science User Facility operated by the ORNL. APT research was supported by the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. The authors would like to thank Dr. Ken Littrell and Dr. Dunji Yu for their help in neutron-scattering measurements. The authors also thank James Burns for his assistance in performing APT sample prep and experiments. 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).