CRYSTALLIZATION REACTIONS IN AMORPHOUS AL ALLOYS INDUCED BY INTENSE PLASTIC DEFORMATION

摘要

Intense plastic deformation of an amorphous Al_(88)Y_7Fe_5 alloy induces shear bands and nanocrystals inside the shear bands. At true strain levels of -11, however, a homogeneous distribution of Al nanocrystals has developed with a nanocrystal density that is similar to those obtained from annealing experiments. Nanocrystals grow inside the shear bands even at near ambient temperatures. While many nanocrystals are single-crystalline, some Al nanocrystals contain dislocations. The average nanocrystal size increases only marginally with deformation and remains at about 12 nm at a true strain of about -12. A prolate morphology of deformation-induced nanocrystals along with the dislocations in the nanocrystals lends new support to the notion of an athermal crystallization process.