The investigation of the effect on crystallization mechanism of the polyhedron type cluster structures in copper-based platinum-palladium alloys with molecular dynamics method

In this study, Copper (Cu)-based Platinum (Pd) and Palladium (Pd) binary alloy systems (Cu-Pt and Cu-Pd) and ternary alloy system (Cu-Pt-Pd) were modelled by Molecular Dynamic (MD) method. Sutton-Chen (SC) Embedded Atom Method (EAM) based on semi-empirical potential energy function was used for molecular dynamic calculations. The fast cooling rate process from liquid phase was applied to occur the amorphous phase for model systems. The systems were waited for investigating the crystallization properties of model systems at different annealing temperatures from amorphous phase for different copper concentrations. The crystallization kinetics of model systems was determined with Avrami coefficients by calculating MD method at different annealing temperatures. The structural developments of model systems were analysed with Radial Distribution Function (RDF). Also, the polyhedron-type atomic clusters which occur in the model systems were obtained by cluster type index (CTIM) method based on Honeycutt-Andersen method from amorphous phase to crystal phase. In both binary and ternary alloy systems, a general increase has occurred in all polyhedron types with the increase of annealing temperature. It has been observed that the presence of crystal type polyhedrons before crystallization in particular affects the crystallization process. For Cu-Pt-Pd model systems, the number of crystal type polyhedron tended to increase regularly as the concentration of copper increased.