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Title: Strength Weakening by Nanocrystals in Ceramic Materials

Abstract

A key question in nanomechanics concerns the grain size effects on materials' strength. Correct solution to this question is critical to design and tailor the properties of materials for particular applications. The full map of grain sizes-hardness/yield stress relationship in metals has been built. However, for ceramic materials, the similar studies and understandings are really lacking. Here we employed a novel technique to comparatively study the mechanical features of titanium dioxide (TiO2) with different crystallite sizes. On the basis of peak profile analysis of the X-ray diffraction data, we determined yield strength for nanocrystalline and bulk TiO2. Our results reveal a remarkable reduction in yield strength as the grain size decreases from 30-40 {mu}m to 10 nm, providing the only evidence of a strength weakening by nanocrystals relative to their bulk counterparts. This finding infers an inverse Hall-Petch effect, the first of its kind for ceramic materials, and a dramatic strength weakening after the breakdown of classic Hall-Petch relation below a characteristic grain size.

Authors:
; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
960041
Report Number(s):
BNL-83027-2009-JA
TRN: US201016%%1185
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nano Letters; Journal Volume: 7
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BREAKDOWN; CERAMICS; DESIGN; GRAIN SIZE; TITANIUM; X-RAY DIFFRACTION; YIELD STRENGTH; MATERIALS; NANOSTRUCTURES; national synchrotron light source

Citation Formats

Wang,Y., Zhang, J., and Zhao, Y. Strength Weakening by Nanocrystals in Ceramic Materials. United States: N. p., 2007. Web. doi:10.1021/nl0718723.
Wang,Y., Zhang, J., & Zhao, Y. Strength Weakening by Nanocrystals in Ceramic Materials. United States. doi:10.1021/nl0718723.
Wang,Y., Zhang, J., and Zhao, Y. Mon . "Strength Weakening by Nanocrystals in Ceramic Materials". United States. doi:10.1021/nl0718723.
@article{osti_960041,
title = {Strength Weakening by Nanocrystals in Ceramic Materials},
author = {Wang,Y. and Zhang, J. and Zhao, Y.},
abstractNote = {A key question in nanomechanics concerns the grain size effects on materials' strength. Correct solution to this question is critical to design and tailor the properties of materials for particular applications. The full map of grain sizes-hardness/yield stress relationship in metals has been built. However, for ceramic materials, the similar studies and understandings are really lacking. Here we employed a novel technique to comparatively study the mechanical features of titanium dioxide (TiO2) with different crystallite sizes. On the basis of peak profile analysis of the X-ray diffraction data, we determined yield strength for nanocrystalline and bulk TiO2. Our results reveal a remarkable reduction in yield strength as the grain size decreases from 30-40 {mu}m to 10 nm, providing the only evidence of a strength weakening by nanocrystals relative to their bulk counterparts. This finding infers an inverse Hall-Petch effect, the first of its kind for ceramic materials, and a dramatic strength weakening after the breakdown of classic Hall-Petch relation below a characteristic grain size.},
doi = {10.1021/nl0718723},
journal = {Nano Letters},
number = ,
volume = 7,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}