Structure evolution of the Fe3C/Fe interface mediated by cementite decomposition in cold-deformed pearlitic steel wires

Cold-drawn pearlitic steel wire is irreplaceably used in industry owing to its outstanding mechanical property which is dominated by the cementite/ferrite (Fe3C/Fe) interfaces in the material. However, the fine structures of the Fe3C/Fe interfaces in the deformed wires are less known to date. In this work, transmission electron microscopic investigation was performed on the atomic structures of the interfaces with the Isaichev orientation relationship (OR) in the wires with progressive deformation strains. In addition to the effect of the dislocation/interface interactions, this work revealed that the deformation-induced partial decomposition of cementite plays an important role in the interface reconstruction during deformation. The interfacial carbon vacancies generated by cementite decomposition and particularly, the amorphization of cementite layers in the sample with epsilon > 1 could effectively annihilated the interfacial dislocations and consequently relaxed the interfacial stress. The correlations between the interface structure changes and the mechanical properties of the wires were discussed. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

This study investigated the atomic structures of cementite/ferrite interfaces in cold-drawn pearlitic steel wire using transmission electron microscopy. The findings revealed that the deformation-induced partial decomposition of cementite plays a crucial role in interface reconstruction, while the amorphization of cementite layers effectively eliminates interfacial dislocations and reduces interfacial stress.