Effects of cooling rate on the microstructure control and liquid–liquid phase separation behavior of Cu–Fe–P immiscible alloys

Abstract

In this article, the influences of cooling rate on the microstructure evolution and liquid–liquid phase separation behavior of Cu–16.2Fe–4.5 P immiscible alloys were systematically investigated. With the cooling rate changing from 1580 K/s to 30 K/s, Cu–16.2Fe–4.5 P metallic samples were still composed of Cu, Fe2P, Fe3P and Cu3P phases according to XRD analyses. With the cooling rate as 1580 K/s, it was observed that Fe–P particles as secondary phase exhibited nearly spherical shape with a uniform dispersion in Cu-rich matrix, which was attributed to the suppressed Marangoni convection and Stokes motion. As the cooling rate decreasing to 30 K/s, an evolving core-shell structure in this alloy was observed to be formed due to the relatively sufficient liquid separation occurrence. Furthermore, it was found that a Fe2P layer was formed to be encapsulated secondary phase, in which Fe3P and Cu particles were also examined. In addition, the microstructure evolution mechanism of Cu–16.2Fe–4.5 P alloys with different cooling rate was also applied.