Methods for characterising the precipitation of nanometer-sized secondary hardening carbides and related effects in tool steels

Nanometer-sized secondary hardening carbides are the most relevant microstr uctural constituents regarding the properties of tool steels. Due to their extreme fineness, direct inspection by microscopy is difficult and time con suming despite the progress recently achieved, e.g. by energy filtering tra nsmission electron microscopy. Indirect methods are therefore additionally employed to obtain more detailed information on the processes taking place. Differential scanning calorimetry and in-situ hot hardness testing are dem onstrated as powerful methods for the determination of kinetic data. In com bination with results from a recently developed tensile specimen and test p rocedure for hard materials with low ductility, more detailed conclusions c an be drawn on the effects of secondary hardening carbides on the strength and the thermal stability.