Nanocrystalline CaO and ZrC as a second phase in amorphous Zr-Cu-Al-Ni matrix composites

This contribution focuses on the case of a metallic glass matrix with nominal composition Zr55Cu30Al10Ni5 blended with increasing volume fractions of CaO or ZrC particles. A comparison with the particle-free metallic glass by means of X-ray diffraction and differential scanning calorimetry analysis shows that the addition of second phase particles does not affect the glass forming ability of the system. The thermal stability of the glass, i.e. the glass transition temperature Tg and the crystallization temperature T,are only slightly affected. Nevertheless, continuous milling is likely to promote dissolution to a limited extent of the ceramic phase into the matrix. This can result in a change of composition and, eventually, in the suppression of the glass transition. Finally, an analysis of isothermal annealing data is presented in order to evaluate the effect of the nanoscaled particles on the kinetics of crystallization.