A microstructure study of nanostructured Fe-Mo+1.5 wt.%SiO2 and+1.5 wt.%TiO2 powders compacted by spark plasma sintering

作者：Cabibbo M^*; Paternoster C; Cecchini R; Fabrizi A; Molinari A; Libardi S; Zadra M

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2008, 496(1-2): 121-132.

DOI：10.1016/j.msea.2008.05.014

• SPS
• TEM
• Nano-indentation
• SiO2 and TiO2
• Nanostructured FeMo steel

Two Fe-1.5wt.%Mo powdered alloys modified with 1.5Wt-%SiO2 and 1.5wt.%TiO2 compacted through spark plasma sintering have been studied. Transmission electron microscopy was used to characterize the nano-scale microstructure. The results showed that sintered FeMo + SiO2 powder is able to keep a nanometric scale grained structure up to a sintering temperature of 815 degrees C. Mean grain size of the FeMo + TiO2 compacted powder maintained its nanometric range up to 900 degrees C. Residual porosity decorates the grain boundary and the triple grain junctions in all the studied sintering conditions. Moreover, nano-porosity accounted for a maximum of 0.26% volume fraction. Direct comparison between X-ray diffraction grain size evaluation (from previously published data) and transmission electron microscopy investigations, showed a significant underestimation when using the first approach. Nano-indentation tests confirmed that the micro-hardness values tend to increase with sintering temperature. Berkovich nano-indentation tests clearly showed that micro-hardness values in nanostructured compacts lead to overestimation of the real hardness values.

• 出版日期2008-11-25