Phase-field-based chemomechanical models for phase transitions and dislocation-microstructure interaction in metallic alloys with application to kappa-carbides

• Applicants: Professor Dr. Franz Roters, since 5/2018; Professor Dr. Robert Svendsen
• Subject Area: Thermodynamics and Kinetics as well as Properties of Phases and Microstructure of Materials ; Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 387118820

The proposed work is concerned with the formulation, comparison and application of phase-field-based chemomechanical models for metallic alloys undergoing phase transitions, dislocation-mediated finite deformation, and failure. On the methodological side, this is based for example on generalization and further development of existing approaches such as WBM (Wheeler-Böttinger-McFadden) and KKS (Kim-Kim-Suzuki) for chemical homogenization to large-deformation chemome-chanics. These will be compared with existing chemomechanical models for small deformation in the context for example of benchmark simulations and the modelling of excess interface energy. In addi-tion, models based on both artificial and physical (i.e., sublattice- and element-site-fraction-based) chemical order parameters will be extended to finite-deformation chemomechanics, facilitating cou-pling to CALPHAD. Likewise, the modelling of dislocation processes and failure will be included via the generalization of phase-field microelasticity for defects and phase-field fracture to finite defor-mation. Principle applications of the proposed method and model developments include the model-ling of precipitation, dislocation-solute interaction, and dislocation-precipitate interaction. Of par-ticular interest in this regard are Fe-Mn-C-Al-based low-density steel kappa-carbides.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1713: Strong Coupling of Thermo-Chemical and Thermo-Mechanical States in Applied Materials
• Ehemaliger Antragsteller: Dr. Pratheek Shanthraj, until 5/2018