[論文レビュー] Tunable dislocations overcome mechano-functional tradeoff in perovskite oxides

Jiawen Zhang, Wenjun Lu+1 more|arXiv (Cornell University)|Feb 23, 2026

Ferroelectric and Piezoelectric Materials被引用数 0

ひとこと要約

The paper shows that seeded dislocations in KTaO3 induce a non-monotonic brittle–ductile–brittle transition and reveal a tradeoff between mechanical durability and functionality as dislocation density changes.

ABSTRACT

Recent advancements in dislocation engineering are reshaping the traditional view towards ceramics being brittle. Here, we use KTaO3 (KTO), a perovskite oxide that is newly discovered with room-temperature bulk plasticity, and demonstrate that the seeded dislocations can effectively tune both mechanical and functional properties. We uncover a novel brittle-ductile-brittle (BDB) transition: low dislocation densities lead to brittle failure, intermediate densities (~10*14 m-2) enable superior ductility with strains over 20%, and high dislocation densities (~10*15 m-2) induce again brittle fracture. This dislocation density-dependent non-monotonic mechanical response challenges the traditional behavior of ceramics and offers new design opportunities. Furthermore, dislocation densities can monotonically decrease thermal conductivity, revealing a tradeoff between mechanical strength and functionality. The findings reveal a critical threshold of dislocation density in optimizing the performance of functional oxides, and provide a new framework for using dislocations to design advanced materials where mechanical durability and enhanced functionality are intertwined.

研究の動機と目的

• Motivate dislocation engineering as a route to overcome ceramic brittleness.
• Demonstrate room-temperature bulk plasticity in KTaO3 (KTO) and how seeded dislocations tune mechanical and functional properties.
• Identify the dislocation-density regimes that lead to different mechanical responses (brittle, ductile, brittle).
• Investigate how dislocation density affects thermal conductivity and functional performance.

提案手法

• Seed and control dislocations in KTaO3 to map mechanical response across dislocation densities.
• Characterize mechanical behavior to identify brittle-ductile-brittle transitions.
• Quantify the relationship between dislocation density and mechanical strength/ductility.
• Assess how increasing dislocation density influences thermal conductivity and functional properties.

実験結果

リサーチクエスチョン

• RQ1 What dislocation density ranges lead to brittle, ductile, and brittle failure in KTaO3?
• RQ2 How do seeded dislocations simultaneously affect mechanical durability and functional properties such as thermal conduction?
• RQ3 Is there a critical dislocation density threshold that optimizes performance in functional oxides?

主な発見

• Low dislocation densities yield brittle failure.
• Intermediate densities (~10*14 m-2) enable ductility with strains over 20%.
• High dislocation densities (~10*15 m-2) induce brittle fracture again.
• Dislocation densities monotonically decrease thermal conductivity, revealing a mechanical–functional tradeoff.
• There exists a critical threshold of dislocation density that optimizes performance in functional oxides.