Mechanically Alloyed Amorphous Ti₅₀(Cu_0.45Ni_0.55)_44–xAl_xSi₄B₂ Alloys with Supercooled Liquid Region

A high-energy ball milling procedure has been developed to produce amorphous alloys in Ti₅₀(Cu_0.45Ni_0.55)_44−xAl_xSi₄B₂ (x= 0, 4, 8, 12) powder mixtures. The milling products were characterized using x-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. The Ti-based amorphous alloy powders prepared through this solid-state process exhibit a well-defined glass transition and a supercooled liquid region (ΔT_x =64 K) close to the largest achieved so far for Ti-based undercooled melts. The substitution of Al for Cu and Ni has beneficial effects on stabilizing the supercooled liquid. Residual nanocrystals of the αTi structure are uniformly dispersed in the amorphous matrix. The composite alloy powders offer the potential for consolidation in the supercooled liquid region to bulk lightweight amorphous alloys and the possibility to attain desirable mechanical properties.