Speaker
Description
Grain boundary (GB) segregation is a crucial factor for controlled engineering of materials properties like toughness, creep resistance, nanocrystalline stability or electrical conductivity. An important first step to tailor such properties is the knowledge of the segregation and precipitation state resulting from specific production processes including heat treatment steps. This calls for a model that connects kinetics of segregation and precipitation to evaluate the non-equilibrium distribution of alloying elements at the GB and in the grain as function of the heat treatment and microstructure.
We present a kinetic segregation model based on the Thermodynamic Extremal Principle (TEP) and its extension to precipitation. The model combines segregation energies from DFT as well as thermodynamic data with microstructure information to compute the distribution of solutes at the GB and in the bulk based on a specified heat treatment. The simulation approach is demonstrated for two different cases: In the first case, we study a Mo alloy and consider precipitation kinetics with MatCalc and subsequent segregation with the developed kinetic model. In the second case, we report on different Fe alloys, where kinetics of segregation and precipitation are treated simultaneously and we discuss the resulting competition effects between GB segregation and precipitation for different heat treatments and compositions.
| Speaker Country | Austria |
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