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

Abstract

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. Some open questions and challenges for engineering dislocations in ceramics are discussed.This article is protected by copyright. All rights reserved

Merits and Demerits of Machine Learning of Ferroelectric, Flexoelectric, and Electrolytic Properties of Ceramic Materials

“…Below the critical dislocation density, on the other hand, dendrite formation may be inevitable because the ionic current is concentrated along dislocations (Figure 17) [57]. Recently, it has been suggested that the introduction of dislocations is useful for improving the functional, electrical and mechanical properties of ceramics, which is called dislocation engineering [62][63][64][65][177][178][179][180]. In many cases, dislocations are introduced into ceramics by applying compressive stress at room temperature or elevated temperatures [62,[177][178][179][181][182][183][184].…”

“…Recently, it has been suggested that the introduction of dislocations is useful for improving the functional, electrical and mechanical properties of ceramics, which is called dislocation engineering [ 62 , 63 , 64 , 65 , 177 , 178 , 179 , 180 ]. In many cases, dislocations are introduced into ceramics by applying compressive stress at room temperature or elevated temperatures [ 62 , 177 , 178 , 179 , 181 , 182 , 183 , 184 ].…”

“…Recently, it has been suggested that the introduction of dislocations is useful for improving the functional, electrical and mechanical properties of ceramics, which is called dislocation engineering [ 62 , 63 , 64 , 65 , 177 , 178 , 179 , 180 ]. In many cases, dislocations are introduced into ceramics by applying compressive stress at room temperature or elevated temperatures [ 62 , 177 , 178 , 179 , 181 , 182 , 183 , 184 ]. Thus, whether high dislocation density such as or more is achievable without the failure of a specimen becomes an issue.…”