Crystallization of amorphous AlDy- and AlDyCo-alloys

Partially or fully amorphous Al89Dy11, Al84Dy11Co5 and Al84Dy6Co10 alloys w ere prepared by melt spinning. The amorphous to crystalline and subsequent transitions were studied with X-ray diffraction, electrical resistivity, th ermal and microhardness measurements. The transformation kinetics were anal ysed in terms of the classical and the generalized Johnson Mehl-Avrami Kolm ogorov models for nucleation and growth processes. In amorphous Al89Dy11, c rystallization begins with alpha(fee Al) formation closely followed by gamm a(Al3Dy), which transforms to alpha(Al3Dy). Addition of Co increases the st ability of the amorphous states. The first crystallization process in the t ernary alloys is eutectic-like; nanocrystals are present in Al84Dy6Co10 Ann ealing in the region of structural relaxation retards subsequent crystalliz ation. (C) 2000 Elsevier Science B.V. All rights reserved.