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Fracture and Deformation in Brittle Solids: A Perspective on the Issue of Scale

Published

Author(s)

Brian R. Lawn

Abstract

The issue of scale in the fracture and deformation properties of ordinarily brittle covalent ionic solids (ceramics) is considered. Characteristic scaling dimensions for nanomechanical properties of this class of solids are identified specimen size or layer thickness, microstructural scale, and contact dimension. Transitions in mechanical damage processes occur as the characteristic dimensions diminish from the macroscale to the nanoscale. Such transitions generally preclude unconditional extrapolations of macroscopic-scale fracture and deformation laws into the nanomechanics region. Strength of brittle solids tends to increase, but toughness to decrease, as the scaling dimensions diminish. The nature of flaws that control strength in the nanoscale region also undergoes fundamental changes even flaws without well-developed cracks can be deleterious to strength. Other, cumulative properties such as wear and fatigue are expected to undergo similar transitional behavior.
Citation
Journal of Materials Research
Volume
19
Issue
No. 1

Keywords

brittle-plastic transition, contact dimension, layer thickness, microstructure scale, nanomechanics, size effects, specimen size

Citation

Lawn, B. (2004), Fracture and Deformation in Brittle Solids: A Perspective on the Issue of Scale, Journal of Materials Research (Accessed April 24, 2024)
Created January 1, 2004, Updated February 19, 2017