Effect of yttrium addition on the non-isothermal crystallization kinetics and fragility of Cu-Zr-Al bulk metallic glass

Abstract Bulk metallic glasses with the composition of Cu 43 Zr 48 Al 9 and (Cu 43 Zr 48 Al 9 ) 98 Y 2 were prepared by copper mold casting technique in this paper. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to investigate their structure and non-isothermal crystallization kinetics. The results show that the influence of heating rate on crystallization is larger than that on glass transition. The crystallization process of (Cu 43 Zr 48 Al 9 ) 98 Y 2 is more sensitive to heating rate than that of Cu 43 Zr 48 Al 9 . Due to Yttrium addition, the glass transition and nucleation process for crystallization become easier, while the grain growth process for crystallization become more difficult based on the activation energies. The Avrami exponents of (Cu 43 Zr 48 Al 9 ) 98 Y 2 decrease at low heating rates, which is totally different from that of Cu 43 Zr 48 Al 9 . These two bulk metallic glasses should be considered as “Intermediately fragile glass formers” according to their fragility indices.