High strength and ductile bulk quasi-crystalline alloys

Quinary Zr-Al-Ni-Cu-(Ag or Pd) amorphous alloys exhibit a double-stage devitrification on heating. Primary devitrification leads to the precipitation of nanoscale icosahedral particles with a size from 20 to 50 nm. High nucleation and low growth rates are obtained in a polymorphous mode for the Ag-containing alloys and a diffusion-controlled mode for the Pd-containing alloys. The nanoscale mixed structure alloys exhibit improved strength and ductility as compared to the corresponding amorphous single-phase alloys.