A probabilistic explanation for the size-effect in crystal plasticity
Event details
| Date | 04.11.2014 |
| Hour | 13:15 › 14:15 |
| Speaker |
Dr. P. Derlet, Condensed Matter Theory Group, Paul Scherrer Institut, Switzerland Bio : In 1995 I obtained a PhD in theoretical physics at Monash University, Australia, in Quantum Field Theory. After training as a school teacher, I did a post-doc at NTNU, Trondheim, Norway on the atomistic modeling of series 6000 Al-Si-Mg and AL-Li alloys. I then moved to Switzerland and worked as a staff scientist at PSI in the group of Helena Van Swygenhoven doing atomistic simulation of nanocrystalline metals. Since 2008, I have been in the Condensed Matter Theory group where I specialize in magnetism in defect dominated materials and the fundamental aspects of plasticity in both crystalline and amorphous solids. |
| Location | |
| Category | Conferences - Seminars |
In this talk, the well-known power-law relation between strength and sample size, 1/d^n, is discussed in terms of the universal properties of a dislocation network and the leading order stress dependence of an underlying critical stress distribution. This approach gives an explicit expression for the the size effect exponent, n=(tau+1)/(alpha+1), where alpha is the leading order algebraic exponent of the low-stress regime of the critical stress distribution and tau is the scaling exponent for intermittent plastic strain activity. This quite general derivation supports the experimental observation that the size effect paradigm is applicable to a wide range of materials, differing in crystal structure, internal microstructure and external sample geometry, and also motivates a new class of deformation experiments investigating strength in terms of both material size and shape.
Practical information
- General public
- Free
Organizer
- IGM-GE
Contact
- Géraldine Palaj