Influence of Quenching Medium on Ordered Phases Formation and Vickers Microhardness of Fe-6.5 Wt%Si

Abstract:

The use of Fe-Si electrical steels in transformer and electrical motor cores requires the material to be cold rolled into thin sheets, as this process efficiently achieves the final dimensions while ensuring desirable magnetic and mechanical properties. For Fe-6.5 wt%Si, hot rolling of this alloy goes well. However, direct cold rolling of the Fe-6.5 wt% Si alloy cause metal cracking due to its inherent brittleness behavior. In this work, we are interested in evaluating the effect of the quenching medium after annealing at 1000°C/1h on the formation of B2 and DO3 ordered phases, which are the main sources of brittleness in the alloy, and on the alloy's mechanical properties. The results show that the quenching in ice-brine reduces the hardness of the material to around 340 HV, with the presence of a cooling rate gradient for each quenching medium, which then causes a micro-hardness gradient. Is shown that an ordering gradient is at the origin of such a harness variation. The size of the ordered domains observed by TEM and the volume fraction of ordered phases measured by XRD decrease after quenching in ice brine, and goes from a continuous form (smoot bending) for quenching in liquid nitrogen to a point form. It is concluded that, the choice of a quenching medium that efficiently removes heat from the sample without changing its physical state can limit the formation of ordered phases in Fe-6.5 wt%Si electrical steel.

• Periodical: Solid State Phenomena (Volume 383)
• Pages: 61-66
• DOI: https://doi.org/10.4028/p-OJJN2j
• Online since: January 2026
• Authors: Touria Badaoui*, Emilie Bérard, Vincent Ji, Yanick Ateba Betanda, Thierry Wackerle, Anne Laure Helbert
• Keywords: Fe-6.5 Wt%Si, Mechanical Properties, Microstructure, Ordered Phases

References

[1] Z. GLAVAS, «THE PROPERTIES OF SILICON ALLOYED FERRITIC DUCTILE IRONS,» METALURGIJA, pp.293-296