Content:
Light Elements and Deformation Mechanisms
This project group covers the topics of alloying with light elements, hydrogen embrittlement and relevant method development. For the topic of alloying with light elements the solid solution, interaction, and diffusion of light elements in body centred cubic (bcc) metals is investigated. We start from the dilute limit and go all the way to precipitation of secondary phases. The focus is on those elements that are expected to have a beneficial effect on the mechanical properties of the alloy or steel, such as boron and carbon. The work is carried out mainly on the basis of ab initio calculations in order to gain a fundamental understanding, but as well to evaluate empirical potentials, parameterize models, or provide input data for mesoscale simulations.
H diffusion near grain boundary.
Methods
Within the project group several models for atomic interactions are employed.
High throughput density-functional theory calculations are used to describe the electronic structure of the investigated systems. From these calculations tight-binding models are derived, that allow predictions of the stuctural stability. Further approximations yield bond-order potentials which can be used to simulate defects and finally (M)EAM type empirical potentials give access to large-scale atomistic simulations.
The thus obtained results enter thermodynamic calculations (CALPHAD/SAPIENS), can be used in kinetic Monte-Carlo simulations for extended time-scales and continuum methods on extended length-scales.
