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Abstract

The combination of accurate first principles calculations with thermodynamic or kinetic concepts opens the door to tackle even advanced engineering problems such as the design of novel high-strength steels with superior mechanical properties. Key to these studies is the highly accurate determination of thermodynamic quantities at finite temperatures. In the first part of the talk it will be shown how novel sampling strategies allow to obtain an amazing coarse graining in configuration space resulting in a reduction from 107 to a few hundred configurations. This enormous reduction permits to employ highly converged density-functional theory calculations thus providing the basis for accurately determining all relevant temperature dependent free energy contributions such as harmonic and anharmonic vibrations, magnetic excitations or defect creation.

The flexibility and the predictive power of this approach will be discussed in the second part of the talk for a few examples relevant to the design and understanding of a new generation of high-strength steels: Determination of mechanisms that provide an adaptive and self-organized response of the materials microstructure on external forces and which are the basis for superior mechanical properties or unraveling critical failure/embrittlement mechanisms.