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THE CRYSTALLISATION OF QUASICRYSTALS IN Ti-BASED SYSTEMS

The crystallisation of Ti45Zr38Ni17 and Ti40Hf40Ni20 systems was investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. Commercially pure elemental powders were used as the starting materials in this study. Powder mixtures were mechanically alloyed for different times. After this the prepared mixtures were heat treated in argon with different heating rates with the temperature ranging from room temperature up to 700º C. The crystallisation temperature and the crystallised phases depended on the system composition and the heat-treatment temperature. The addition of Zr or Hf to the Ti/Ni based system results in changes to the structural and thermal properties. The crystallised phases were identified by XRD analysis, while the thermal properties were determined by DSC. The kinetic parameter – activation energy – for all the measured systems was obtained from the DSC data by applying Kissinger΄ s non-isothermal model.

CRYSTALLISATION; QUASICRYSTALS; Ti-BASED SYSTEMS

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