Condensed Matter Physics Seminar

Collective effects of dislocations on microscale plasticity

Stefano Zapperi
University of Rome, Sapienza
Monday, June 18
Higgins 235, 2 pm

The stress-strain curves of plastically deformed microcrystals display widely distributed bursts, in stark contrast with macroscopic samples where plasticity appears as a smooth process. By combining three-dimensional simulations of the dynamics of interacting dislocations with statistical analysis of the corresponding deformation behavior, we determine the burst size distribution and establish its dependence on microcrystal size.

The results are used to assess the implications of strain bursts for plastic forming processes. For sample dimensions on the micron and sub-micron scale, burst-like deformation is shown to impose fundamental limits on formability.