Rethinking brittleness in ceramics: The emergence of room-temperature plasticity

Ceramics are valued for their high strength, thermal stability, and chemical inertness, but their structural applications are limited by intrinsic room-temperature (RT) brittleness. The stress required for dislocation motion in strongly ionic/covalent ceramics often exceeds their fracture strength, leading to catastrophic failure before plastic deformation occurs. Overcoming this limitation remains a major challenge in materials science. Recent studies have shown that ceramics exhibit RT plasticity through mechanisms including dislocation, phase transformation, and grain boundary sliding (GBS). These findings challenge the conventional view of ceramics as purely brittle materials and suggest that plasticity can be achieved not only in microscale specimens but also in bulk and structurally engineered ceramic systems. Several strategies have been developed to promote RT plasticity. Defect engineering, the controlled introduction and activation of dislocations, is critical for regulating deformation behavior. Structural designs such as coherent interfaces, layered architectures, and amorphous–crystalline composites can reduce dislocation nucleation barriers and improve deformation compatibility. Nanocrystalline structuring and external field regulation further enhance plasticity by altering local stress distributions and diffusion pathways. in situ characterization and strain measurement techniques have enabled direct observation and accurate quantification of deformation processes, improving the understanding of the relationship between structure, defects, and mechanical response. Despite these advances, achieving reliable and scalable plasticity in bulk ceramics remains challenging. Future work should focus on intrinsical plastic ceramic systems, scalable fabrications, and integrated multiscale design strategies. These efforts may enable the development of ceramics with improved damage tolerance and deformability for advanced structural and functional applications.