| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
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| Symposium
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Advances in Multi-Principal Element Alloys II
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| Presentation Title |
J-57: Neutron Diffraction and Total Scattering Investigation of an Unusual Long-range Order-Disorder Transition Competing with Short-range Ordering in 10-component Oxides |
| Author(s) |
Dawei Zhang, Yan Chen, Heidy Vega, Tianshi Feng, Dunji Yu, Michelle Everett, Joerg C Neuefeind, An Ke, Renkun Chen, Jian Luo |
| On-Site Speaker (Planned) |
Dawei Zhang |
| Abstract Scope |
Neutron diffraction and total scattering are combined to investigate a series of single-phase 10-component compositionally complex fluorite-based oxides (10CCFBOs) A long-range order-disorder transition (ODT) occurs at x = 0.81 ± 0.01, from the ordered pyrochlore to disordered defect fluorite. In contrast to ternary oxides, this ODT occurs abruptly without an observable two-phase region; moreover, the phase stability in 10CCFBOs deviates from the well-established criteria for simpler oxides. Rietveld refinements of neutron diffraction patterns reveals the detailed atomistic mechanism of the ODT. We further discover short-range weberite-type order in Nb-rich compositions based on diffuse scattering and small-box modelling. Interestingly, the weberite-type short-range order emerges before the ODT, coexisting and interacting with long-range pyrochlore order, and persist into the long-range disordered defect fluorite structure after the ODT. Notably, a drop in the thermal conductivity is coincident with emergence of the short-range order, instead of the long-range ODT. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Characterization, Ceramics, High-Temperature Materials |