Formation and crystallization of ZrCuTi metallic glasses

Abstract

We report the suction casting of Zr₆₅Cu₂₇Ti₈ bulk metallic glasses with diameters up to 1 mm. While the substitution of Ti for Cu increases the glass forming ability significantly, the onset crystallization temperature and the width of the supercooled liquid region decrease. This decrease is due to the appearance of an icosahedral quasicrystal phase, which crystallises from the glass at a lower temperature than the Zr₂Cu devitrification product in the Zr₆₅Cu₃₅ glasses. Based on the results of recent structural studies of undercooled Ti/Zr-based alloys, this likely reflects the formation of icosahedral order in the undercooled liquid, which increases the nucleation barrier for the Zr₂Cu phase during the quench, making glass formation easier.

Acknowledgements

The authors gratefully acknowledge the support from the National Science Foundation under grant DMR 03–07410.