Modeling of Microstructure Changes in FePt Nano-Granular Thin Films Using the Phase-Field Method

Abstract

Since the factors that influence microstructure formation are extensive (e.g., alloy composition, heat treatment condition, etc.), quite a lot of experimental trial-and-error is often necessary when searching for the best combination of desired microstructure and material properties, even when the basic mechanism of microstructure formation is understood. During the last decade, the phase-field method has emerged across many fields in materials science as a powerful tool to simulate and predict complex microstructure evolution. Since phase-field methodology can model complex microstructure changes quantitatively, it is possible to search for the most desirable microstructure by using this method as a design simulation, i.e., through computer trial-and-error testing. In order to establish this methodology, first of all, quantitative modeling of complex microstructure changes using the phase-field method is required. The objective of this study is to model the FePt nano-granular structure formation and the order-disorder phase transition of FePt nano-particles as a typical example of phase-field modeling. We show that it is possible to model FePt nano-granular structure formation quantitatively using the phase-field method. This modeling method may also be applicable to various types of granular structure formation. The simulation result also suggests that there is a size dependence on the ordering of FePt nano-particles. Using the phase-field method to model the microstructure evolutions proved to be a very effective strategy in predicting and analyzing the complex microstructure formation.