Cyclic phase transformations of mechanically alloyed Co75Ti25 powders Original Research Article

Cyclic crystalline–amorphous–crystalline phase transformations have been investigated during high-energy ball milling of a mixture of elemental Co75Ti25 powder under an argon gas atmosphere. The results have shown that the single amorphous phase, which is obtained after 11 ks of mechanical alloying time, transforms into a new metastable phase of nanocrystalline bcc-Co3Ti upon milling for 86 ks. However, it transforms to the same amorphous phase upon further milling (360 ks). The present work shows the effects of the milling time and the milling speed on the structure of the mechanically alloyed powders.