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

提出的工作是关于金属合金经历相变，位错介导的有限变形和破坏的基于相场的化学力学模型的制定，比较和应用。在方法方面，这是基于现有方法的推广和进一步发展，如WBM （Wheeler-Böttinger-McFadden）和KKS (Kim-Kim-Suzuki)，用于大变形化学组动力学的化学均质化。这些将与现有的小变形化学力学模型进行比较，例如基准模拟和过量界面能量建模。此外，基于人工和物理（即基于亚晶格和元素位点分数）化学顺序参数的模型将扩展到有限变形化学力学，促进与CALPHAD的耦合。同样，通过将相场微弹性推广到缺陷和相场断裂到有限变形，将包括位错过程和破坏的建模。该方法的主要应用和模型的发展包括沉淀、位错-溶质相互作用和位错-沉淀相互作用的建模。在这方面特别令人感兴趣的是fe - mn -c - al基低密度钢卡帕碳化物。

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.