CRYSTALLIZATION BEHAVIOR OF AMORPHOUS TI-NI-CU ALLOY RIBBONS

Abstract

Amorphous Ti50Ni(50-x)Cux (at.%) (x = 15, 20 and 25) alloy ribbons were prepared by melt spinning, and then their crystallization behavior was investigated by optical microscopy, transmission electron microscopy, X-ray diffraction and differential scanning calorimetry. Wavenumber (Qp) decreased from 29.40 nm(-1) to 29.29 nm(-1) and Delta T (T-g - T-x) increased from 31 K to 36K with increasing Cu content from 15 at.% to 25 at.%, suggesting that glass forming ability of Ti-Ni-Cu alloy ribbons increased with increasing Cu content. Activation energy for crystallization decreased from 211.5 kJ/mol to 136.4 kJ/mol with increasing Cu content from 15 at.% to 25 at.%, suggesting that a stability of Ti-Ni-Cu amorphous decreased with increasing Cu content.