Amorphous Ti–Cu–Ni–Al alloys prepared by mechanical alloying

Tix(CuNi)90–xAl10 (x = 50, 55, 60) amorphous powder alloys were synthesized by mechanical alloying technique. The evolution of amorphization during milling and subsequent heat treatment was investigated by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry and transmission electron microscopy. The fully amorphous powders were obtained in the Ti50Cu20Ni20Al10, Ti55Cu17.5Ni17.5Al10 and Ti60Cu15Ni15Al10 alloys after milling for 30, 20 and 15 h, respectively. Differential scanning calorimetry revealed that thermal stability increased with the increasing (CuNi) content: Ti60Cu15Ni15Al10, Ti55Cu17.5Ni17.5Al10 and Ti50Cu20Ni20Al10. Heating of the three amorphous alloys at 800 K for 10 min results in the formation of the NiTi, NiTi2 and CuTi2 intermetallic phases.