Synthesis of Amorphous/Nanocrystalline Ni-Ti Biomaterial Powders by Mechanical Alloying

An amorphous/nanocrystalline 50Ni-50Ti powder was produced from elemental Ti and Ni powders by solid state synthesis utilizing low energy mechanical alloying with times up to 100 hr. The morphology, microstructure and phase composition of the milling products were evaluated by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The results indicated that there was no chemical reaction between the elements during the milling process, which led to the direct for mation of an amorphous/nanocrystalline structure without any intermediate phase (intermetallic and/or solid solution phase) formation. It seems that the second kind of amorphization process proposed by Weeber and Bakker is governed. It was shown that the formation of amorphous phase was started after 80hr and developed during the milling for 100hr.