Devitrification behaviour of Cu-Zr-Ti-Pd bulk glassy alloys

The glass formation, mechanical properties and devitrification of the Cu-Zr-Ti-Pd glassy alloys are studied. The formation of a nanoscale icosahedral phase in Cu-based alloys is observed. The nanoscale particles with icosahedral symmetry are primarily formed in the Cu-Zr-Ti-Pd glassy alloys in the initial stage of the devitrification process. As the icosahedral phase is metastable it transforms to the equilibrium oC68 (Cu, Pd)10(Zr, Ti)7 single phase or its mixture with the oP44 Cu8Zr3 phase, depending upon the alloy composition, through an intermediate crystalline compound. The structure changes on heating were studied by X-ray diffraction, transmission electron microscopy, differential scanning calorimetry and isothermal calorimetry.