Chill block melt spinning of nickel-molybdenum alloys

Samples of Ni-Mo alloys ranging in composition from pure nickel to Ni-40 at % molybdenum were cast by the chill block melt spinning rapid solidification technique and examined by optical metallography, X-ray diffraction, and microhardness testing. Casting difficulties were encountered with lean alloys, but richer alloys spread more readily on the casting wheel. Alloy microstructures for 5 to 37.5 at % molybdenum ribbons were primarily cellular/dendritic; microstructure feature size decreased with increasing molybdenum content. Extended solubility of molybdenum in -nickel, with f c c lattice parameter increasing with composition to the 1.05 power, was observed up to 37.5 at % molybdenum. Substoichiometric Ni-Mo () nucleated on the wheel side of the ribbons of compositions 35, 37.5, and 40 at % molybdenum. The amount of partitionless phase thus formed increased with increasing molybdenum content and quench rate. This substoichiometric transformed readily to a fine structured - mixture.