Abstract

The nanoscale plastic deformation of yttria-stabilized tetragonal zirconia (YSTZ) is highly dependent on the crystallographic orientations, i.e., dislocation is induced when the loading direction is 45° tilted to {111} and {101} slip planes, while tetragonal to monoclinic phase transformation dominates the plastic deformation when loading direction is perpendicular to the slip planes. This study investigates the effects of specimen size and yttria concentration on the mechanical response of single crystalline YSTZ nanopillars. Through uniaxial compression test, the smaller-is-stronger phenomenon is revealed in nanopillars deformed through a dislocation motion mechanism. Serrated stacking faults are observed in the smallest nanopillar, while neat primary slip plane forms in the largest nanopillar. In contrast, the larger-is-stronger relation is observed in nanopillars in which deformation is mediated by tetragonal to monoclinic phase transformation. It is noted that the ratio of transformed monoclinic phase to the remaining tetragonal phase is the highest in the smallest nanopillar. The strength of nanopillars is identified to decrease by increasing the amount of yttria due to the creation of more oxygen vacancies that act as weak points to facilitate dislocation motion and accelerate phase transformation.

Department(s)

Materials Science and Engineering

Comments

The authors are grateful for computer time allocation provided by the Extreme Science and Engineering Discovery Environment (XSEDE), Award No. TG-DMR140008.

Keywords and Phrases

Compression testing; Crystalline materials; Nanostructures; Oxygen vacancies; Phase transitions; Plastic deformation; Stacking faults; Zirconia, Crystallographic orientations; Dislocation motion; Loading direction; Mechanical response; Single-crystalline; Tetragonal to monoclinic phase transformations; Uni-axial compression tests; Yttria stabilized tetragonal zirconias, Yttria stabilized zirconia

International Standard Serial Number (ISSN)

0021-8979; 1089-7550

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2017 The Authors, All rights reserved.

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