Internal Friction Behavior Associated with Martensitic Decomposition in Low-carbon Dual-phase Steel

Abstract

In this study, the martensitic decomposition behaviors of a low-carbon dual-phase steel were investigated by the low-frequency internal friction method, combined with various structural analysis techniques including X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Two internal friction peaks were observed at 418.4°C and 448.1°C, and were attributed to desolventization of supersaturated carbon atoms from martensite and formation of Cr3C7 precipitates, respectively. The results indicated that the two-step process during the martensitic decomposition, involving carbon atom diffusion and carbide precipitation, could be well explained by the internal friction technique. The microstructural mechanisms associated with the generation of the two internal friction peaks during the martensitic decomposition are discussed.