Aging process in ferrite during isothermal decomposition of austenite in 0·1 C–2Mo steel

Abstract

Austenite containing (wt-%) about 0·1C–2Mo held in the range 600–700°C transforms to ferrite or ferrite + eutectoid depending on the transformation time. It has been shown by means of transmission electron microscopy that an aging process takes place in the ferrite resulting in precipitation of the alloy carbides. After only 1 min holding at 700°C the very early stages of the precipitation process are visible in the ferrite and after 5 min at 700°C very small M₂₃C₆ particles can be identified. M₂₃C₆ is subsequently replaced by Mo₂C which becomes practically the only carbide present after 1 h holding at 700°C.