Transmission electron microscopy characterization of the interfacial structure of a galvanized dual-phase steel

Abstract

Site-specific studies were carried out to characterize the interface of a galvanized dual-phase (DP) steel. Focused ion beam (FIB) was used to prepare specimens the interface region (~100 nm thick) between the coating and the substrate. Transmission electron microscopy (TEM), scanning TEM (STEM) and high resolution TEM (HRTEM) were performed to resolve the phases and the structures at the interface between the zinc (Zn) coating and the steel substrate. The STEM and TEM results showed that a continuous manganese oxide (MnO) film with a thickness of ~20 nm was present on the surface of the substrate while no silicon (Si) oxides were resolved. Internal oxide particles were observed as well in the sub-surface region. Despite the presence of the continuous oxide film, a well-developed inhibition layer was observed right on top of the oxide film. The inhibition layer has a thickness of ~100 nm. Possible mechanisms for the growth of the inhibition layer were discussed.

Optimization of the Continuous Galvanizing Heat Treatment Process in Ultra-High Strength Dual Phase Steels Using a Multivariate Model

“…Several authors have investigated the behavior of dual phase steels during processing in continuous annealing and galvanizing lines [3][4][5][6][7][8][9][10]. For example, Calcagnotto et al [3] studied the effect of temperature and time of intercritical austenitization on the microstructure and properties produced in dual phase C-Mn steels with an ultra-fine initial microstructure composed of ferrite and perlite.…”

Efecto de la composición química en el comportamiento mecánico de recubrimientos galvanizados por inmersión en caliente: una revisión

“…Las microfisuras inducidas en el proceso de solidificación ocurren a menudo en el recubrimiento galvanizado • 18, julio-diciembre de 2017 debido al gran desajuste entre los coeficientes de expansión térmica del recubrimiento de zinc y el sustrato de acero, esto puede influir significativamente en la densidad de grietas que se forman en la capa de zinc, y en la posterior delaminación del recubrimiento bajo carga. Los granos de zinc muestran una fuerte tendencia de propiedades mecánicas anisotrópicas, causadas por su estructura cristalina hexagonal, lo cual influye a su vez sobre la deformación y el comportamiento de la capa de zinc [20].…”

Development of 2NN MEAM potential for Fe–Al and atomistic investigation of surface and interface properties of the inhibition layer in galvanized Fe

“…Extensive electron microscopy observations have been performed on the intermetallic phases and interfacial structures of galvanized AHSSs over the past few decades [11][12][13][14]. These observations revealed that the thickness of the interface zone in which metallurgical reactions occurred during galvanizing was on the order of ∼100 nm.…”

“…These observations revealed that the thickness of the interface zone in which metallurgical reactions occurred during galvanizing was on the order of ∼100 nm. In this nanoscale interface zone, formation of the inhibition layer and various intermetallic phases, as well as the reactions between the inhibition layer and the existing surface oxides on the steel substrate occur in a short time period (on the order of seconds) [11,12]. As a result, it is challenging to conduct experimental studies on the complex reactions on such fine spatial and temporal scale.…”