Abstract
Two continuum mechanical models of crystal plasticity theory namely, conventional crystal plasticity theory and mechanism-based crystal plasticity theory, are used to perform a comparative study of stresses that are reached at and ahead of the crack tip of a bicrystal niobium/alumina specimen. Finite element analyses are done for a stationary crack tip and growing cracks using a cohesive modelling approach. Using mechanism-based strain gradient crystal plasticity theory the stresses reached ahead of the crack tip are found to be two times larger than the stresses obtained from conventional crystal plasticity theory. Results also show that strain gradient effects strongly depend on the intrinsic material length to the size of plastic zone ratio (l/R0). It is found that the larger the (l/R0) ratio, the higher the stresses reached using mechanism-based strain gradient crystal plasticity theory. An insight into the role of cohesive strength and work of adhesion in macroscopic fracture is also presented which can be used by experimentalists to design better bimaterials by varying cohesive strength and work of adhesion.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 665-689 |
| Number of pages | 25 |
| Journal | International journal of plasticity |
| Volume | 23 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 2007 |
Funding
The presented work is funded by the Deutsche Forschungsgemeinschaft within the Graduiertenkolleg “Internal interfaces in Crystalline Materials”, which is gratefully acknowledged. Thanks are also due to Prof. M. Finnis, Dr. R.M. Cannon and Dr. I. Scheider for useful discussion.
Keywords
- Cohesive model
- Macro/micro fracture analysis
- Mechanism-based strain gradient crystal plasticity
- Metal/ceramic interface
ASJC Scopus subject areas
- General Materials Science
- Mechanics of Materials
- Mechanical Engineering