1Advanced Materials Research Center, Islamic Azad University, Najafabad Branch, Isfahan, Iran.
2Department of Materials Engineering, Isfahan University of Technology, Isfahan, Iran.
Amorphous alloys has been taken into consideration because of their unique properties and are nominated as the future engineering materials. In this research, the effect of Ni and milling time on amorphization process and thermal stability of Ti50Cu50-xNix(x=10, 15, 25 at%) alloy system were investigated. The evolution of amorphization during milling, thermal stability and subsequent heat treatment were evaluated by x-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results showed that alloys reached to the highest content of amorphous phase in Ti50Cu40Ni10, Ti50Cu15Ni35 and Ti50Cu25Ni25 alloy compounds after 60, 40 and 10 hours respectively. Differential scanning calorimetry showed thermal stability of amorphous alloy, exhibiting a distinct glass transition and crystallization temperature and a wide supercooled liquid region for Ti50Cu25Ni25 powder alloy with a value about 45 k. Heating Ti50Cu25Ni25 amorphous alloy at 943 k for 10 min results in the formation of intermetallics such as CuTi and NiTi2 phases. In addition, mechanical properties of amorphous powders were studied by Vickers microhardness test. The alloy with 25 percent Ni showed The high value of hardness about 884 Hv after 40 hours milling.