CAST BULK ZR57TI5AL10CU20NI8 AMORPHOUS ALLOY WITH TENDENCY OF PHASE-SEPARATION

Zr-Ti-Al-Cu-Ni alloys show excellent grass forming ability (GFA). Amor phous cylindrical samples of diameter from 8 to 20 mm were produced by casting the Zr57Cu20Al10Ni8Ti5 alloy melt into a copper mould. The Zr 57Cu20Al10Ni8Ti5 amorphous alloy shows some particular crystallization characteristics: measurements by differential scanning calorimetry (D SC) reveal three exothermic peaks in the DSC traces at continuous heat ing. The third peak of the highest peak temperature shifts towards low er temperature with the decrease of the cooling rates at which the amo rphous alloys were formed, while the first two peaks remain unchanged. Isothermal annealing near the glass transition temperature causes the third peak shifting towards a definitive temperature and then it beco mes quite stable during further annealing. The shift of the third peak is attributed to the tendency of phase separation of the alloy. (C) 1 997 Elsevier Science S.A.