Abstract
The precipitation of χ-carbide and its transition to cementite during the tempering of high carbon martensite have been investigated by means of transmission electron microscopy.
The χ-carbide and the cementite were formed on the transformation twin interfaces and the orientation relationships among these two carbides and the twinned ferrites were determined. The carbide planes parallel to the twin plane were the (530)χ for χ-carbide and the (101)c for cementite. It was shown that these habits could theoretically be explained by the establishment of the low surface energy planes on the twin interfaces. These crystallographic results support the in situ transformation of χ-carbide to cementite.
