On the microstructure of rapidly quenched Co-10 wt.% TaC

Rapidly quenched alloys provide an opportunity to study the different phases of transformation that take place during solidification. Structural defects such as stacking faults and overlapping stacking faults, observed in different parts of disc samples, initiated this study, which sets out to explain the mechanism for the transformation from fcc to hcp in Co-TaC solid solution. The observed defects can be regarded as nuclei for the transition from one close-packed structure to the other. This paper describes phenomena related to the Co-10 wt.% TaC alloy, and draws comparisons between these and the martensitic transformations in pure Co, in other Co-based alloys, and in steels.