Abstract
Metastable phases can exist within local minima in the potential energy landscape when they are kinetically “trapped” by various processing routes, such as thermal treatment, grain size reduction, chemical doping, interfacial stress, or irradiation. Despite the importance of metastable materials for many technological applications, little is known about the underlying structural mechanisms of the stabilization process and atomic-scale nature of the resulting defective metastable phase. Investigating ion-irradiated and nanocrystalline zirconia with neutron total scattering experiments, we show that metastable tetragonal ZrO2 consists of an underlying structure of ferroelastic, orthorhombic nanoscale domains stabilized by a network of domain walls. The apparent long-range tetragonal structure that can be recovered to ambient conditions is only the configurational ensemble average of the underlying orthorhombic domains. This structural heterogeneity with a distinct short-range order is more broadly applicable to other nonequilibrium materials and provides insight into the synthesis and recovery of functional metastable phases with unique physical and chemical properties.
| Original language | English |
|---|---|
| Article number | eadq5943 |
| Journal | Science Advances |
| Volume | 11 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 3 2025 |
| Externally published | Yes |
Funding
This work is dedicated in memory of Rod Ewing. Funding: This work was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, under award DE-SC0024140. A.P.S. acknowledges support from the University Nuclear Leadership Program through an NEUP Fellowship. The research at ORNL’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US DOE. This research also used the x-ray powder diffraction beamline of the National Synchrotron Light Source II, a US DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. The results presented here are based on a UMAT experiment, which was performed at the X0-beamline of the UNILAC at the GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany) in the Acknowledgments: this work is dedicated in memory of Rod ewing. Funding: this work was supported by the US department of energy, Office of Science, Basic energy Sciences, under award de-Sc0024140. A.P.S. acknowledges support from the University nuclear leadership Program through an neUP Fellowship. the research at ORnl’s Spallation neutron Source was sponsored by the Scientific User Facilities division, Office of Basic energy Sciences, US dOe. this research also used the x-ray powder diffraction beamline of the national Synchrotron light Source ii, a US dOe Office of Science User Facility operated for the dOe Office of Science by Brookhaven national laboratory under contract no. de-Sc0012704. the results presented here are based on a UMAt experiment, which was performed at the X0-beamline of the UnilAc at the GSi helmholtzzentrum fuer Schwerionenforschung, darmstadt (Germany) in the frame of FAiR Phase-0. Author contributions: A.P.S. and M.K.l. conceived and designed the study. i.M.G. and G.B. synthesized the nanocrystalline sample. A.P.S. prepared samples for ion irradiation and characterization by x-ray and neutron scattering techniques. c.t. managed the ion irradiation experiments. J.n. aided with neutron scattering measurements and data reduction. J.l. and X.G. analyzed the eXAFS data. A.P.S. and e.c.O. performed the Rietveld and small-box refinements. A.P.S. and G.B. constructed and refined the supercell model. A.P.S., e.c.O., M.K.l., and R.c.e. wrote the manuscript with input from all authors. Competing interests: the authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials.