Precipitation in the Fe-38 at.% Al-1 at.% C alloy

The microstructure and crystallization behavior of a conventionally cast Fe-38 at.% Al-1 at.% C alloy and a set of crystals obtained from this alloy by the Bridgman and the floating-zone methods were investigated. A significant redistribution of elements during crystallization was observed. A two-phase microstructure of the κ-phase in the B2 matrix was found in regions with composition below 37 at.% Al and 0.5 at.% C. A microstructure consisting of the κ-phase and B2 matrix with a limited amount of graphite globules was obtained in the fast-solidified Bridgman sample. An enhanced growth of graphite lathes in the Bridgman crystal was observed at a growth rate of 28 mm h−1. These graphite lathes were oriented parallel to the {100} and {110} planes. The κ-phase precipitates have no orientation relationship with the matrix.