Place: DPG Spring Meeting 2011, Dresden, Germany
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. While ab-initio density-functional theory provides an accurate description of the electronic and mechanical properties of metallic systems, the methodology is prohibitively expensive when applied to larger multi-component systems. While empirical interatomic potentials can be applied to such systems, there are significant question marks over the transferability of these models when applied to systems to which they have not been fitted. 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 "standard" approach which is applicable to all elements which are relevant to the steel industry, and which can be applied directly within existing scale-bridging methodologies. We have therefore developed a general tight-binding approach for the simulation of complex metallic alloys, in which the parameterisation is obtained directly from ab-initio calculations. In order to assess the quality and transferability of the approach, we have extensively applied the resulting models to a wide range of alloy structures.