Mechanical tailoring of dislocations in ceramics at room temperature: A perspective

The potential of dislocations (line defects) in ceramics may have been greatly underrated until most recently. Promising proofs-of-concept have been demonstrated for dislocation-tuned functional and mechanical properties, revealing a new research front for dislocations in ceramics for a wide range of potential applications. However, it is commonly known that ceramics are hard (difficult to deform) and brittle (easy to fracture), particularly at room temperature. It remains a great challenge to mechanically tailor dislocations in ceramics. To address this pressing bottleneck, this article discusses the mechanics-based dislocation engineering in ceramics by examining the three fundamental factors of dislocation nucleation, multiplication, and motion. Successful experimental approaches to tune dislocation density and plastic zone size on single-crystal strontium titanate are demonstrated. The dislocation-based competition between plastic deformation and crack formation is discussed. The aspects of coupling external fields to manipulate dislocations are highlighted, which may hold the key to modulating the charged dislocation cores in ceramics and opening new routes for mechanical tailoring of dislocations at room temperature. ... mehrSome open questions and challenges for engineering dislocations in ceramics are discussed.