Role of Cracks in the Creep of Structural Polycrystalline Ceramics.
Abstract
A study was conducted of the role of crack formation in the non-linear stress-strain behavior of a fine-grained polycrystalline aluminum oxide at high temperature under conditions of displacement-rate-controlled mechanical loading. The observed deformation behavior could be divided into three regimes. At the lowest values of deformation rate the load levelled off to a constant value without crack formation, consistent with deformation by diffusional creep. Over a range of intermediate values of deformation considerable non-linear deformation took place, manifested by a decrease in stress with increasing strain as the result of strain-softening due to the formation and growth of cracks. At the highest rates of displacement, specimen fracture occurred by the formation of a single crack without significant non-linear deformation and without the formation of additional cracks. These results are discussed in terms of the general mechanisms and kinetics of the deformation of non-ductile solids. Keywords: Crack propagation; Cracking; Ceramics; Aluminum; Crystal lattices; Composite materials.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 15, 1988
- Accession Number
- ADA191485
Entities
People
- Anuradha Venkateswaran
- D. P. Hasselman
- Kimberly Y. Donaldson
Organizations
- Virginia Tech