A multi‐scale methodology for the analysis of metallic interfaces

Metallic interfaces, such as grain boundaries, phase boundaries and metallization layers, play a dominant role in bulk materials, functional materials and metallic microdevices in defining their strength, reliability and life time properties.

PhD candidate: Ir. Paul R.M. van Beers
Supervisor: Prof. dr. ir. Marc G.D. Geers
Daily supervisor: Dr. ir. Varvara G. Kouznetsova
Financing: STW

In single phase metals, the deformation behavior at grain boundaries becomes more important for increasing grain boundary-to-volume ratio.  At present, grain boundary modelling lacks the critical interaction between plasticity and interfaces, which takes place at the level of individual dislocations. Micromechanical observations from molecular dynamics simulations and experiments indicate that dislocations can be accumulated, transmitted, absorbed or nucleated at interfaces.

At the polycrystalline continuum scale, conventional modelling of interfaces in gradient enhanced crystal plasticity frameworks only allows to incorporate the limiting situations of either impenetrable or completely transparent grain boundaries through the high-order boundary conditions. In this research, a grain boundary interface model is developed by means of thermodynamically consistent constitutive equations for plasticity through interfaces.

This project is in collaboration with the Delft University of Technology and the University of Groningen. A multi-scale approach is employed to improve and define constitutive rules emanating from the interactions of discrete dislocations from molecular dynamics and discrete dislocation dynamic analyses.