Amorphisation Process during Mechanical Alloying of Al-Fe-Ti Powders and Crystallisation of the Milling Products

摘要

In the present work, an elemental equiatomic powder mixture of Al, Fe, and Ti was mechanically alloyed in a high-energy ball mill. The phase transformations occurring in the material during milling and during subsequent heating in a calorimeter were studied with the use of X-ray diffraction. The results obtained show that an amorphous phase is formed during performed mechanical alloying process. However, some differences in the diffraction halo profile of the amorphous phase at different stages of the milling process were observed. It was also found that the products of crystallisation of the amorphous materials characterised by dissimilar diffraction halo were different. Crystallisation product of 10 h-milled sample was identified as a mixture of τ₂ phase and Fe(Al,Ti) solid solution, while of 30 h-milled sample as a nanocrystalline AlFeTi intermetallic phase with B2 structure and the lattice parameter 2.951 ?. These results, as well as dissimilarity between calorimetric curves of the powders after 10 and 30 h of milling, indicate that different amorphous phases were formed at the different stages of the mechanical alloying process.