Solid-state amorphization during mechanical alloying of Fe-xTi alloys (x = 33.3 and 50 at.%) and the subsequent mechanically-induced crystallization by continued ball milling was studied. In the case of Fe50Ti, it was revealed that by milling of Fe and Ti powders, firstly the nanocrystalline FeTi intermetallic compound forms, and then, the amorphous phase appears. In the case of Fe-33.3Ti, the amorphous phase formed directly and at lower energies. Continued milling of the Fe-33.3Ti system resulted in the devitrification of the powder with the appearance of the diffraction peaks of nanocrystalline α-Fe. For unambiguous analysis of the amorphization, the quantitative XRD amorphization parameter was taken into account. Examination of the milled powders revealed that, despite the dominance of fracturing compared to cold welding, the size of powder particles refines tremendously due to the amorphization and the brittleness it brings in the system. Conclusively, this works revealed some of the unknown aspects of amorphization in this system.