Effect of grain size on mechanical properties of nanocrystalline materials
- Univ. of Toronto, Ontario (Canada). Dept. of Metallurgy and Materials Science
- Queen`s Univ., Kingston, Ontario (Canada). Dept. of Materials and Metallurgical Engineering
The possibility of a dislocation mechanism in the deformation process of nanocrystalline materials is reviewed and analyzed. The present theoretical calculation, by taking the anisotropic characteristic of crystallographic symmetry and different choices of critical shear strength into account, results in a reasonable limit in grain size for applying dislocation pile-up theory to nanocrystalline materials. The deviation from the Hall-Petch relationship is rationalized in terms of a small number dislocation pile-up mechanism. A composite model is proposed to evaluate the strength of nanocrystalline materials. It is shown that this model can be used for interpreting the various cases observed in Hall-Petch studies. An analytical expression for assessing the creep rate of nanocrystalline materials by a diffusion mechanism, including triple line diffusion, is derived. It is predicted that the creep rate due to triple line diffusion will exhibit a stronger grain size dependence than that due to grain boundary diffusion.
- OSTI ID:
- 27884
- Journal Information:
- Acta Metallurgica et Materialia, Journal Name: Acta Metallurgica et Materialia Journal Issue: 2 Vol. 43; ISSN 0956-7151; ISSN AMATEB
- Country of Publication:
- United States
- Language:
- English
Similar Records
Competing Grain Boundary and Interior Deformation Mechanisms with Varying Sizes
Deformation mechanism crossover and mechanical behaviour in nanocrystalline materials.