Crystallization of amorphous AlDy- and AlDyCo-alloys

Abstract Partially or fully amorphous Al 89 Dy 11 , Al 84 Dy 11 Co 5 and Al 84 Dy 6 Co 10 alloys were prepared by melt spinning. The amorphous to crystalline and subsequent transitions were studied with X-ray diffraction, electrical resistivity, thermal and microhardness measurements. The transformation kinetics were analysed in terms of the classical and the generalized Johnson–Mehl–Avrami–Kolmogorov models for nucleation and growth processes. In amorphous Al 89 Dy 11 , crystallization begins with α (fcc Al) formation closely followed by γ (Al 3 Dy), which transforms to α (Al 3 Dy). Addition of Co increases the stability of the amorphous states. The first crystallization process in the ternary alloys is eutectic-like; nanocrystals are present in Al 84 Dy 6 Co 10 . Annealing in the region of structural relaxation retards subsequent crystallization.