Materials Science and Engineering A, 375-377(1-2 SPEC. ISS.):171-177, 2004. Paper abstract bibtex
The nanocrystalline state is often viewed in terms of isolated nanocrystalline particles, but an equally important form of nanostructured alloys is based upon a dispersion of a high number density of nanocrystals or upon a bulk nanocrystalline microstructure. In a number of marginal glass-forming alloys with compositions that limit the solute content to <15at.%, nanocrystal densities of 1021 to 1023m-3 can develop during primary crystallization and offer exceptional magnetic and structural performance. There is also a remarkable thermal stability of the dispersed nanocrystal and amorphous matrix microstructure to significant change in size scale. Several proposals involving solute effects, phase separation or quenched-in nuclei and heterogeneous nucleation have been advanced to account for the high nanocrystal density. Alternatively, other approaches involving alloying by intense cold-rolling reveal that a deformation-induced amorphization can be achieved for marginal glass-forming alloy compositions. In other systems, a deformation-induced nanocrystal synthesis can be observed during the cold-rolling of amorphous ribbons. These developments represent a major level of microstructure control. © 2003 Elsevier B.V.