NEUTRON-DIFFRACTION AND NEUTRON SMALL-ANGLE SCATTERING STUDY OF THE AMORPHIZATION REACTION IN NI50MO50

The solid state amorphisation reaction in a Ni50Mo50 alloy has been in vestigated by neutron diffraction and small angle scattering for a ser ies of specimens mechanically alloyed for 2, 4, 8, 16 and 32 h. In the initial stages of the reaction, deformation of the parent crystalline phases occur. After 8 h of treatment, a change in the samples is obse rved and those treated for 16 and 32 h consist of an amorphous NiMo ph ase with some free molybdenum. Small angle scattering graphs of log I( Q) vs. log Q show a sequence of changes which correspond to the sequen ce of changes seen in the diffraction data, The graphs for the 2 and 4 h samples are linear over an extended range of scattering vector, Q. The slope of the graphs is about -3.4 which is indicative of a rough s urface having fractal character between the transformed and untransfor med regions of the samples