| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Environmentally Assisted Cracking: Theory and Practice
|
| Presentation Title |
Accelerating Diffusion, Plasticity, Grain Growth and Crack Propagation by Hydrogen and Carbon |
| Author(s) |
Reiner Kirchheim |
| On-Site Speaker (Planned) |
Reiner Kirchheim |
| Abstract Scope |
Within the defactant concept the formation energy of crystalline discontinuities of the first kind like vacancies, dislocations, grain boundaries and surfaces is decreased. Thus substitutional diffusion by the vacancy mechanism is accelerated. Motion of discontinuities with higher dimensions is not cooperative but occurs by generation of discontinuities of the second kind like kink pairs on dislocations or disclinations (facets) on grain boundaries. Then the motion of discontinuities of the first kind may be controlled by the generation rate and mobility of discontinuities of the second kind. Solute segregation reduces motion by the well-known solute drag. The defactant concept predicts a reduced formation energy for discontinuities of the second kind. Therefore, the generation of these discontinuities becomes easier being finally responsible for the accelerated plasticity, grain growth and crack propagation. Deacceleration occurs by solute drag controlling the motion. Experimental results are presented supporting this general thermodynamic background of solute/defect-interaction |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |