TEM Characterization of Two Spark Plasma Sintered Fe-1.5wt.%Mo Steels Stabilized with SiO₂ and TiO₂

Abstract:

This paper presents a transmission electron microscopy study of two Fe-1.5wt.%Mo steels stabilized with 1.5wt.%SiO2 and 1.5wt.%TiO2,respectively, and compacted through spark plasma sintering. The microstructure inspections revealed that sintered FeMo+SiO2 is able to maintain a nanometric scale grained structure up to a sintering temperature of 815°C, while the steel modified with TiO2 retained its nanometric scale microstructure up to 900°C. The ultra-fine grained structure (within 100-150 nm) was also directly correlated to the grain boundary stability through systematic extinction contours survey. Local nano-welding phenomena shows the effective compacting process of the Fe-Mo powders during sintering. Residual nano-porosity was found to decorate most of the grain boundaries and the triple grain junctions in all the sintering conditions examined, although this nano-porosity accounted for values within 0.26% in volume fraction.

• Periodical: Materials Science Forum (Volumes 604-605)
• Pages: 187-201
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.604-605.187
• Online since: October 2008
• Authors: Marcello Cabibbo
• Keywords: Nanostructured FeMo Steel, SiO₂, Spark Plasma Sintering (SPS), TEM, Titania (TiO₂)

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