Interaction of amorphous fullerene C60 with austenite Fe-Ni alloy at high temperatures and pressures

Interaction of amorphous fullerite C-60 with austenitic Fe-33.2 wt.% Ni alloy at pressures 0-8 GPa and temperatures 600-1100 degrees 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)(3)C, 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, hardness at micro- and nanoindentation turned out to be significantly higher than those at 8 GPa. During sintering amorphous fiillerite 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. (C) 2015 Elsevier B.V. All rights reserved.