Calendar Details

For more information about item submission and attendance, see About the Technical Calendar.

Wednesday, May 08

Predicting the Deformability and Strength of Noncrystalline Materials

James Langer, University of California, Santa Barbara, Santa Barbara
Joint Institute for Neutron Sciences Seminar
11:00 AM — 12:00 PM, JINS, Building 8630, Room A-202
Contact: Hope Moore-Webb (hmoore2@utk.edu), 865.576.8630

Abstract

Predictive theories of noncrystalline plasticity must contain two basic ingredients: (1) A dynamic model of flow defects, i.e. the analogs of dislocations in crystals; and (2) A thermodynamic measure of the structural disorder that determines the populations and behaviors of these defects. It is becoming increasingly clear, in a widening variety of physical circumstances, that the relevant flow defects are two-state shear transformation zones (STZ's), and that the relevant measure of disorder is the effective temperature, i.e. the thermodynamic temperature of just the structural degrees of freedom. In this presentation, I will illustrate recent progress, with applications primarily to bulk metallic glasses, by showing results for stress-strain-strain rate relations, frequency-dependent viscoelastic responses, and fracture toughness. If time permits, I will say more about the theoretical principles.