Bridging the Gap between Bulk Compression and Indentation Test on Room-Temperature Plasticity in Oxides: Case Study on SrTiO3

Xufei Fang,Kuan Ding,Lukas Porz,Atsutomo Nakamura

doi:10.3390/cryst10100933

Xufei Fang, Kuan Ding + Show 2 more

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https://doi.org/10.3390/cryst10100933

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Abstract

Dislocation-based functionalities in inorganic ceramics and semiconductors are drawing increasing attention, contrasting the conventional belief that the majority of ceramic materials are brittle at room temperature. Understanding the dislocation behavior in ceramics and advanced semiconducting materials is therefore critical for the mechanical reliability of such materials and devices designed for harvesting the dislocation-based functionalities. Here we compare the mechanical testing between indentation at nano-/microscale and bulk uniaxial deformation at macroscale and highlight the dislocation plasticity in single crystal SrTiO3, a model perovskite. The similarities and differences as well as the advantages and limitations of both testing protocols are discussed based on the experimental outcome of the crystal plasticity, with a focus on the pre-existing defect population being probed with different volumes across the length scales (“size effect”). We expect this work to pave the road for studying dislocation-based plasticity in various advanced functional ceramics and semiconductors.

Highlights

Dislocations, one-dimensional line defects, are one of the major carriers of plastic deformation in crystalline materials
Even though some cracks may form in the SrTiO3 crystal, which is often inevitable, dislocation-based deformation can continue to a large plastic strain, unless the crystal shatters
In order to comprehensively compare the similarities/differences and advantages/limitations between bulk and indentation tests on ceramic materials, we summarize the relevant aspects in Table

Summary

Introduction

Dislocations, one-dimensional line defects, are one of the major carriers of plastic deformation in crystalline materials. There has been increasing attention on dislocation-based functionality in ceramic materials in recent years [1,2,3,4,5,6,7], albeit the common belief is that the majority of ceramic materials are brittle. A substantial number of ceramics and semiconductors (single crystal) can be deformed plastically by dislocations at room temperature [8,9,10,11,12,13,14]. There are three endeavors being made to introduce dislocations into ceramics As many applications are processed, used or stored at room temperature, this work will mainly focus on the dislocation behaviors at room temperature.

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