Compositional effects on the mechanochemical synthesis of Fe–Ti and Cu–Ti amorphous alloys by mechanical alloying

It is well-known that the mechanochemical processing of binary mixtures of transition metals can induce the formation of nanostructured and amorphous phases. Previous kinetic studies have shown that the phase transformation in binary mixtures follows sigmoidal conversion curves irrespective of the intensity of mechanical processing. The rate of such transformations is instead strongly influenced by both the intensity of the mechanical treatment and the physical properties of the reactant powders. In the present work, we give additional information on the amorphisation kinetics of binary mixtures by exploring the effect of composition on the transformation kinetics. Cu–Ti and Fe–Ti mixtures with composition within the amorphisation ranges have been subjected to mechanical processing at fixed intensity. The kinetics of phase transformation has been followed by quantitative X-ray diffraction. The experimental data obtained demonstrate that the amorphisation rate has a strong dependence on the product of the mass fractions of the single reactants.