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Title: Effect of crystallites on surface damage and fracture behavior of a glass-ceramic

Abstract

A study was conducted of the effect of crystallization on the fracture toughness, strength, and resistance to surface damage of glass-ceramic materials with a range of microstructures obtained by different heat treatments. The hardness indentation method was used as a quantitative tool to simulate mechanical surface damage. In the uncrystallized glass and in the glassceramic heat-treated to result in a uniform fine-grained structure, crack size increased monotonically with indentation load. In contrast, in the glass-ceramics heat-treated to result in a microstructure consisting of larger crystallites (a few micrometers) contained within a fine-grained matrix, a discontinuity in the crack size vs load curve presented evidence for crackpinning at crack sizes which were a small multiple of the intercrystallite spacing. At the position of crack-pinning, the fracture toughness showed a discontinuous increase with increasing crack size that was attributed to crack deflection. The strength of the glass and fine-grained glass-ceramic measured in biaxial flexure decreased monotonically with indentation load. The strength at low values of indenter load of the glassceramic heat-treated to yield the coarser crystallites within the fine-grained matrix was independent of indentation load, indicating stable crack propagation prior to fast fracture. At the higher values of indenter load, the coarse-grainedmore » glassceramics exhibited a monotonic decrease in strength with increasing indentation load. The results of this study indicate that the strengthening observed on crystallization of a glass can be attributed to a combination of a decrease in flaw size achieved at a given mechanical surface treatment, an increase in fracture toughness, and a modification in the mode of crack propagation.« less

Authors:
; ;
Publication Date:
Research Org.:
Department of Materials Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
OSTI Identifier:
6266189
Resource Type:
Journal Article
Journal Name:
J. Am. Ceram. Soc.; (United States)
Additional Journal Information:
Journal Volume: 66:10
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CERAMICS; CRYSTALLIZATION; FRACTURE PROPERTIES; GLASS; CRACK PROPAGATION; FLEXURAL STRENGTH; HARDNESS; HEAT TREATMENTS; MECHANICAL TESTS; MICROSTRUCTURE; CRYSTAL STRUCTURE; MATERIALS TESTING; MECHANICAL PROPERTIES; PHASE TRANSFORMATIONS; TESTING; 360603* - Materials- Properties; 360203 - Ceramics, Cermets, & Refractories- Mechanical Properties

Citation Formats

Morena, R, Husselman, D P.H., and Niihara, K. Effect of crystallites on surface damage and fracture behavior of a glass-ceramic. United States: N. p., 1983. Web. doi:10.1111/j.1151-2916.1983.tb10528.x.
Morena, R, Husselman, D P.H., & Niihara, K. Effect of crystallites on surface damage and fracture behavior of a glass-ceramic. United States. https://doi.org/10.1111/j.1151-2916.1983.tb10528.x
Morena, R, Husselman, D P.H., and Niihara, K. 1983. "Effect of crystallites on surface damage and fracture behavior of a glass-ceramic". United States. https://doi.org/10.1111/j.1151-2916.1983.tb10528.x.
@article{osti_6266189,
title = {Effect of crystallites on surface damage and fracture behavior of a glass-ceramic},
author = {Morena, R and Husselman, D P.H. and Niihara, K},
abstractNote = {A study was conducted of the effect of crystallization on the fracture toughness, strength, and resistance to surface damage of glass-ceramic materials with a range of microstructures obtained by different heat treatments. The hardness indentation method was used as a quantitative tool to simulate mechanical surface damage. In the uncrystallized glass and in the glassceramic heat-treated to result in a uniform fine-grained structure, crack size increased monotonically with indentation load. In contrast, in the glass-ceramics heat-treated to result in a microstructure consisting of larger crystallites (a few micrometers) contained within a fine-grained matrix, a discontinuity in the crack size vs load curve presented evidence for crackpinning at crack sizes which were a small multiple of the intercrystallite spacing. At the position of crack-pinning, the fracture toughness showed a discontinuous increase with increasing crack size that was attributed to crack deflection. The strength of the glass and fine-grained glass-ceramic measured in biaxial flexure decreased monotonically with indentation load. The strength at low values of indenter load of the glassceramic heat-treated to yield the coarser crystallites within the fine-grained matrix was independent of indentation load, indicating stable crack propagation prior to fast fracture. At the higher values of indenter load, the coarse-grained glassceramics exhibited a monotonic decrease in strength with increasing indentation load. The results of this study indicate that the strengthening observed on crystallization of a glass can be attributed to a combination of a decrease in flaw size achieved at a given mechanical surface treatment, an increase in fracture toughness, and a modification in the mode of crack propagation.},
doi = {10.1111/j.1151-2916.1983.tb10528.x},
url = {https://www.osti.gov/biblio/6266189}, journal = {J. Am. Ceram. Soc.; (United States)},
number = ,
volume = 66:10,
place = {United States},
year = {1983},
month = {10}
}