Experimental and computational study of cementite precipitation in tempered martensite

In this work, we investigate cementite precipitation during tempering of quenched 0.3C–1Cr–1Mo steel with martensitic microstructure at temperatures between 400 and 700 °C. Particular focus is laid on the evolution of the Cr-content of particles during tempering, where we observe a transition from fast C diffusion-controlled to slow Cr diffusion-controlled kinetics. For characterization of the precipitates, transmission electron microscopy (TEM) in combination with thermokinetic simulation is applied. With a new concept for treatment of inner-particle diffusion in the framework of the SFFK model implemented in the software MatCalc, a successful simulation of cementite precipitation kinetics and Cr enrichment of precipitates is carried out over the entire temperature range.