The kinetics of the reverse transformations from a mixture of bainitic ferrite and residual austenite to austenite have been investigated in a steel containing a relatively high silicon concentration. It was found that the reaustenitization process was initially rapid but slow at the end of reaction and the extent of austenite formed increased with increasing reaustenitization temperature until all of the bainitic ferrite had been transformed to austenite. The process of reaustenitization was followed by dilatometry, optical and transmission electron microscopy, and stereology. The results suggested that the formation of austenite took place by the movement of planar ferrite/austenite interfaces.
JOURNAL OF MATERIALS SCIENCE, 1993, Vol.28, No.12, pp.3137-3144Bainite