Experimental and computational study of cementite precipitation in tempered martensite

摘要

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 degrees 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.