Neutron diffraction study of metal-matrix composite with fullerite

Interaction of amorphous fullerite C60 with austenitic Fe-33.2 wt. % Ni alloy at pressures 0-8 GPa and temperatures 600-1100 °C was studied by neutron diffraction. The amorphous fullerite was obtained by ball milling and mixed with the powder of the crystalline alloy. The interaction at sintering led to the dissolution of carbon in fcc Fe-Ni solid solution and the formation of carbide (Fe, Ni)3C, but the Fe-Ni-C alloy did not undergo phase transformations and preserved the original fcc structure. As a result, the alloy hardened, we could also witness a clear barometric effect: at the pressure of 2 GPa the amount of the dissolved carbon and the microhardness turned out to be significantly higher than those at 8 GPa. During sintering amorphous fullerite is undergoing phase transitions and its microhardness is higher than the microhardness of the metal component. At high temperatures of interaction graphite appears. The presence of Fe-Ni alloy in the composite reduces the temperature of graphite formation in comparison with transformations in the pure amorphous fullerene.