Effects of C Addition on the Microstructures of As-Cast Cu-Fe-P Alloys

Effects of C addition on the microstructures of as-cast Cu-Fe-P (mass fraction) alloys were systematically investigated. The results show that C addition can refine the matrix microstructure and make Fe particles finer. The Fe particles observed in both the non-C-alloyed and C-alloyed specimens are alpha-Fe particles, which possess a body-centered cubic (bcc) structure with a Nishiyama-Wassermann orientation relationship with the matrix. C is reported to be an gamma-Fe stabilizer in the literature. The reason for the difference between the phases of Fe particles observed in this study, and that reported in the literature, are finally discussed. Additionally, C addition facilitates the decomposition of the supersaturated solid solution which occurs by the simultaneous precipitation of very fine Fe particles. Such initial decomposition product has an face-centered cubic (fcc) structure with a cube-on-cube orientation relationship with the matrix.