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Bulk and Thin Film Synthesis of Compositionally Variant Entropy-stabilized Oxides
Published on: May 29, 2018
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Ultra-dense dislocations stabilized in high entropy oxide ceramics
Yi Han1, Xiangyang Liu1, Qiqi Zhang2
1State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China.
Nature Communications
|May 24, 2022
Summary
Researchers have stabilized ultra-dense dislocations in complex oxide ceramics, enhancing fracture toughness. This breakthrough offers a new method for tuning ceramic material properties.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Ceramic Engineering
Background:
- Dislocations are crucial in metals but their role in oxide ceramics is underestimated.
- Rigid bonding in oxides limits dislocation density and stability, hindering property control.
Purpose of the Study:
- To investigate the stabilization of ultra-high density dislocations in oxide ceramics.
- To explore the impact of compositional complexity on dislocation behavior and material properties.
Main Methods:
- Synthesizing oxide ceramics with large compositional complexity.
- Characterizing dislocation density and distribution using advanced microscopy.
- Analyzing thermodynamic stability and fracture toughness.
Main Results:
- Achieved ultra-high density (∼10^9 mm^-2) of uniformly distributed edge dislocations in complex oxide ceramics.
- Demonstrated thermodynamic stabilization of dislocations via entropy gain with increasing compositional complexity.
- Observed crack deflection and bridging, leading to a ~70% enhancement in fracture toughness.
Conclusions:
- A controllable method for creating ultra-dense dislocations in oxide ceramics has been developed.
- Dislocation stabilization in ceramics is achievable through compositional complexity, compensating for strain energy.
- This approach offers a novel pathway for engineering ceramic properties, particularly fracture toughness.
