From non-planar dislocation cores to non-associated plasticity and strain bursts
✍ Scribed by J.L. Bassani; V. Racherla
- Publisher
- Elsevier Science
- Year
- 2011
- Tongue
- English
- Weight
- 593 KB
- Volume
- 56
- Category
- Article
- ISSN
- 0079-6425
No coin nor oath required. For personal study only.
✦ Synopsis
In non-close-packed crystalline lattices, e.g. of bcc metals and intermetallic compounds, the stress-state dependence of the Peierls barrier for the motion of a screw dislocation violates Schmid's law and leads to non-associated plastic flow at the continuum level. Plasticity models based upon distinct yield and flow functions are developed for both single crystals and polycrystalline aggregates that build upon atomic-level simulations of single dislocations. For a random polycrystal, isotropic forms for those functions are proposed and used to study mechanisms of macroscopic deformation. Nonassociated flow is shown to have a significant effect on strain localization. Intermittent strain bursts are predicted to arise as a consequence of non-associated flow, particularly for deformations close to the plane strain state and for nearly rate-insensitive response.