TY - CONF A1 - Wang, Lei A1 - Darvishi Kamachali, Reza T1 - Density-based Thermodynamics of Microstructure Defects N2 - Systematic microstructure design requires reliable thermodynamic descriptions and phase diagrams of each and all microstructure elements. While such descriptions are well established for most bulk phases, thermodynamic assessment of crystal defects is greatly challenged by their individualistic aspects. In this talk, we present a density-based thermodynamic concept to describe defects based on available bulk thermodynamic data. Here dealing with grain boundaries (GBs), we apply this concept to compute GB (phase) diagram. Applications to segregation engineering of GBs in bulk and nanocrystalline alloys will be presented. We further develop this model to include the effect of elastic interactions due to atom size mismatch and obtain the corresponding GB (phase) diagram for the ternary Al-Cu-Li system. T2 - TMS 2021 CY - Online meeting DA - 15.03.2021 KW - Microstrucrue Design KW - Density-based Thermodynamics PY - 2021 AN - OPUS4-52337 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Darvishi Kamachali, Reza T1 - Interfacial Spinodals N2 - Despite their finite spatial extent, interfaces can have profound impacts on microstructure properties. This is because of their distinct phase-like properties distinguishing them from the adjacent homogeneous bulk structure. When noticed by solute atoms, interfaces can experience their own chemical phase changes. In this talk, we investigate the constrained states of chemically decomposed phases at interfaces. A density-based theory of interfaces is proposed to describe the confined chemical decomposition at general grain boundaries. Here the grain boundary is viewed as a lesser dense, defected structure with reference to the corresponding bulk structure. Using this picture, the thermodynamic origins of interfacial spinodal phenomena are revealed. We also show that transient interfacial spinodals can be activated over a large alloy composition range, enabling kinetic engineering of interfacial chemistry. T2 - TMS 2021 CY - Online meeting DA - 15.03.2021 KW - Microstrucrue Design KW - Spinodal Decomposition KW - Interfacial Spinodal PY - 2021 AN - OPUS4-52338 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -