Unnikrishnan, R., Carruthers, A., Cao, S., Rogers, S. R., Kwok, T. W., Thomas, R., Dye, D., Bowden, D., Francis, J. A., Preuss, M., & Pickering, E. (2024). Development of novel carbon-free cobalt-free iron-based hardfacing alloys with a hard π-ferrosilicide phase. Materialia, 35, 102107. https://doi.org/10.1016/j.mtla.2024.102107
Abstract:
Recently, iron-based alloys with a π-ferrosilicide phase have emerged as potential alternatives to cobalt-based hardfacing alloys. Here, we present the development of two π-ferrosilicide containing alloys: one with a ferritic matrix and the other with a ferritic-austenitic matrix. In the as-cast condition, both alloys revealed fine Ni- and Si-rich coherent cubic shaped D03 precipitates in the BCC matrix. The π-ferrosilicide phase was found to have an orientation relationship with the ferrite phase, nucleating within ferrite matrix and from ferrite grain boundaries. In contrast to carbide-strengthened hardfacing Fe-alloys, here the dissolution of the π-ferrosilicide phase at 1200 °C enables easy thermomechanical processing of these alloys, which results in refinement of the π-ferrosilicide and additional formation of χ-phase precipitates in the ferrite. Nano-scratch tests provided evidence of a resilient silicide-ferrite interface, likely to due to it possessing some coherency. Both alloys also displayed compressive strengths approaching 2 GPa and ductility in compression of approximately 25 %. The combination of processability and attractive mechanical properties suggests that these alloys have the potential to serve as alternatives to carbide-reinforced hardfacing Fe-alloys.
License type:
Attribution 4.0 International (CC BY 4.0)
Funding Info:
The authors would like to acknowledge EPSRC grant EP/R000956/1
, EP/T016728/1 and EP/P006566/1 for funding the project.
This work was also supported by the Henry Royce Institute for Advanced Materials, funded through EPSRC grants EP/R00661X/1
, EP/S019367/1, EP/P025021/1 and EP/P025498/1.