Abstract
Direct visualization at 1873 K of 0% to 8% molten FeAl droplets suspended in a SiO2 enriched oxide medium was carried out to image the evolution of droplet morphology during reaction between Al and SiO2. Phenomena such as perturbation growth, necking and budding of offspring droplets from a bulk body are observed. The observations are used to discuss and inform a new approach to the nature of interfacial tension and the impact this has on concepts used to define interfacial tension for a two phase system with material exchange across the interface. The mapping of global interfacial tension coupled with free energy dissipation has been used to give an energetic reasoning as to the behaviour seen with respect to aluminium content in the metal phase.
Highlights
Interfacial tension between molten oxide slurries and liquid steel controls the rate of reaction where material exchange between the two phases is concerned
As a result the steel industry finds itself in a position where the development of high aluminium content grades such as TRIP and low density products is no longer a luxury but a necessity in order to stay competitive in the market in comparison to materials such as light metals, composites or carbon fibre
Due to the dynamic environment produced within the high-temperature confocal scanning laser microscope (HT-CSLM) sample it is very challenging to locate the metal droplet; high levels of light gain and brightness are used to locate the droplet between the slag melting point and the beginning of meaningful video recording before settings are returned to those suitable for imaging
Summary
Interfacial tension between molten oxide slurries and liquid steel controls the rate of reaction where material exchange between the two phases is concerned. A high aluminium alloyed steel offers the potential for a stronger lighter material in comparison to those currently available Such an alloy presents product issues such as grain refinement due to the lack of phase change, as well as processing chemical stability with both ladle slurries and mould flux compositions due to the high SiO2 content favourable for both viscosity and melting point influences. Where species in [] are in within the liquid metal phase, and those in () are in the molten oxide phase In systems such as these at liquid temperatures it is well documented that the reactions at the interface are much faster than material mass transfer within the bulk phases. This has previously been reported as a broadening of a metal droplet during sessile drop interrogation[1] (reduced contact angle) or in the case of an unbound metal droplet mixing of the two phases into a micro emulsion[2, 3]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
