Time: 3:15. p.m.
Place: CCS2011 Seminar Series Talk, Institute for Pure and Applied Mathematics, Los Angeles, USA
The mechanical properties of steels are greatly influenced by their composition and structure. Depending on processing conditions, as e.g. the speed of cooling and the tempering temperature, different phases are formed. Some of these phases exhibit rather complex crystallographic structures. Applying atomistic simulation techniques to study the formation and growth of these phases can provide detailed insight into the underlying mechanisms and help to find ways to prevent or control the formation of those phases. An important step in analysing the simulations is to identify the different phases in a structure. For this we have developed a polyhedron analysis method that is based on the distinct geometrical features of complex crystal phases. Within our approach we analyse the local coordination polyhedra around each atom in the structure, as well as a fingerprint for each polyhedron. The fingerprint reflects the arrangement of polyhedra within the polyhedron network. The distribution of polyhedra together with the fingerprints can then be used to determine the structure of the complex phases.