Harvesting room-temperature plasticity in ceramics by mechanically seeded dislocations

TL;DR

This paper demonstrates a novel method to significantly enhance room-temperature plasticity in ceramics by mechanically seeding dislocations, enabling ductile behavior without high-temperature treatments.

Contribution

It introduces a simple approach to seed mobile dislocations in ceramics at room temperature, promoting plasticity and suppressing brittle fracture.

Findings

Achieved plastic strains beyond 30% in ceramics.

Seeded dislocations trigger multiplication via cross slip.

Method works across multiple length scales.

Abstract

The quest for room-temperature ductile ceramics has been repeatedly fueled by hopes for large-scale applications but so far has been not successful. Recent demonstrations of enhanced functional properties in ceramics through judicious dislocation imprint, however, have been sparking renewed interest in dislocation plasticity in brittle ceramics. Here, we propose a facile approach using room-temperature mechanically seeded mobile dislocations with a density of ~10^14/m^2 to significantly improve the room-temperature plasticity of ceramics with a large plastic strain beyond ~30%. The seeded mobile dislocations trigger profuse dislocation multiplication via cross slip and motion. Hence, they offer an avenue to suppress brittle fracture and harvest plasticity in ceramics without any additional high-temperature process. We employ both in situ nano-/micromechanical deformation and ex situ bulk deformation to bridge the length scales. This finding tackles the pressing bottleneck of dislocation engineering in ceramics for achieving ductile ceramics and harvesting both versatile mechanical and functional properties.