From the Electronic Structure to the Macroscopic Behavior: A Multi-scale Analysis of Plasticity in Intermetallic Compounds

Abstract

ABSTRACTThe influence of crystal interfaces related to stacking faults on the properties of >110< superdislocations and hence on the temperature dependences of the yield stress in intermetallic compounds is investigated. This is achieved by a combination of the ab-initio density functional electron theory (which describes the electronic scale) with the generalized Peierls-Nabarro model (which describes the atomistic scale). For Pt3Al and doped Al3Ti our data do not support the hypothesis that the strong increase of the yield stress with decreasing T at low T results from sessile SISF-bound dislocation dissociations. Alternative explanations are suggested. For Ni3Al our results do not rule out the idea that Kear-Wilsdorf locks are responsible for the experimentally observed anomalous temperature dependence of the yield stress.