An apparatus for the production of amorphous alloy ribbon is described. The alloy is inductionmelted in a small quartz crucible and ejected by argon gas pressure through a small orifice in the bottom of. the crucible. The liquid jet impinges at a small angle with respect to a radius of a copper disk rotating at several thousand rev/min, flattens while rapidly cooling and solidifying, and leaves the circumferential surface of the disk as a result of centrifugal force. The resulting ribbon geometry for an alloy of Fe40Ni4 BZO has been studied as a function of orifice sizes bepween 340 and 480 U m in diameter, of disk speeds between 5 and 10x103 r e v / m i n (20 and 40 m / s e c ) , a n d of ejection pressures between 4 and 10 psig (28 and 70 kPa). The cross-sectional area of the ribbon can be predicted quite accurately from the disk speed, the orifice diameter, and the velocity of the liquid jet as given by the Bernoulli equation. Experimental data are in the form of ribbon thicknesses, ranging between 10 and 40 U r n , and m a s s / length, ranging between 0 -0 5 and 0.24 mglmm. None of the ribbons pro&uced showed any signs of crystallinity, as determined by X-ray diffraction.
The microstructure and the average grain size were investigated by x-ray diffraction and transmission electron microscopy for nanocrystalline (n) Ni-P alloys with 18, 19, and 22 at.% P. A detailed study of the nanocrystalline states obtained along different heat treatment routes has been performed: (1) a-->ni by isothermal annealing of the melt-quenched amorphous (a) Ni-P alloys; (2) ni-->nii by isothermal annealing of the nanocrystalline ni state; (3) ni-->nii by linear heating of the ni state. The heats evolved during the structural transformations were determined by differential scanning calorimetry. From these studies, a scheme of the structural transformations and their energetics was constructed, which also includes previous results on phases obtained by linear heating of the as-quenched amorphous state of the same alloys. Grain boundary energies also have been estimated. In some cases it was necessary to assume a variation of the specific grain boundary energy during the phase transformation to understand the enthalpy and microstructure changes during the different heat treatments.
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