ICAMS / Interdisciplinary Centre for Advanced Materials Simulation


Tight-binding simulation of complex metallic alloys

Date: 24.06.2011
Place: Thomas Young Centre, University College, London, UK

Eunan McEniry
Georg Madsen
Ralf Drautz

The interplay between various co-existing phases of metallic alloys is a key factor in the determination of the strength, ductile and magnetic properties of modern steels. Ab-initio density-functional theory provides an accurate description of the electronic and mechanical properties of metallic systems, but is prohibitively expensive when applied to larger multi-component systems. While interatomic potentials can be applied to such systems, there are significant question marks over the transferability of these models. The tight-binding approach lies in an intermediate region, enabling the simulation of several thousands of atoms, while retaining the essential physics of bonding and cohesion in solids.

The aim of the present work is to produce a systematic scale-bridging approach based on the tight-binding methodology, which is applicable to the full block of transition metals, in which the parametrisation is obtained directly from ab-initio calculations. The model is applied to a wide range of complex alloy structures in order to assess the quality and transferability of the approach. An further spatial coarse-graining is then introduced, which enables the screening of highly complex multicomponent structures, while retaining both chemical and size effects.

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