Integrated Computational Materials, Process and Product Engineering – IC-MPPE 2022

Mechanical properties of metals and alloys depend critically on the microstructure, for e.g., yield strength increases with a decrease in average grain size, also known as the Hall-Petch effect. During thermomechanical treatments, microstructure processes such as grain growth and recrystallization significantly modify the average grain size and grain size distributions. Both these processes involve the migration of high-angle grain boundaries that are sensitive to the grain boundary structure and alloying additions. Grain boundary migration rates in metals, quantified by intrinsic mobility and solute segregation determined from the segregation energy are both anisotropic properties of a grain boundary. Nevertheless, most experimental studies assume effective grain boundary mobility and segregation energy as adjustable parameters to describe grain growth rates. Here, the phase-field method is used to simulate grain growth with anisotropic grain boundary properties to determine the representative grain boundary mobility and segregation energy. A critical discussion will be presented to identify the limits where a representative grain boundary can be defined. Within these limits, a representative segregation energy for solute elements informed from DFT simulations will be used to identify the candidate solute elements that may promote grain refinement of austenite in steels at high temperatures.