Project area C comprises local structure-, defect-, and chemical analysis,
characterization of technologically relevant mechanical properties, evaluation of the local texture and anisotropy, description of the failure mechanisms under mechanical load, as well as a detailed analysis of the relationship between lattice defects and internal strain in the system Fe-Mn-C.
In the third application phase, the focus continues on the characterization of nanostructured microstructures and their mechanical properties. Here, a large number of experimental observations have to be verified and needs to be made available for a congruent description of the material behavior.
The focus of subproject C1 "Microstructural analysis" lies on high-resolution analysis of interfaces. In the context of the analysis of material-relevant mechanical properties in C2 additionally a comprehensive macroscopic characterization of the laboratory materials is done and fatigue is quantified. Specific features of short range ordering phenomena for the interpretation of the observed properties are evaluated. Graded model systems with planar interfaces produced by Physical Vapor Deposition (PVD) methods are used in C3 to study local mechanical properties in order to provide input data for modeling plasticity and damage.
The description of twinning under cyclic loading is a focus in C4. The analysis of the damage mechanisms and the limits of the ductility in single- and multiphase materials under multiaxial stress takes place in C6. In C8, the 3D quantification of the chemical composition on the nanometer scale using APT is used for the analysis of kappa-phase systems. The influence of the kappa-gamma phase boundary coherence stresses on the stability of kappa carbides at finite temperatures is determined in A2 by ab initio calculations and is compared with measurements from C8. Calculated energies of antiphase boundaries of kappa carbides are used to evaluate transport measurements in C8. In C10, heat treatment is used to systematically vary the size, morphology, dispersion and chemical composition of the austenite phase in order to study their effects on the deformation- and strengthening-behavior in multiphase medium manganese Steels.