Study of amorphous phase in Fe100−x(NbTiTa)x alloys synthesized by mechanical alloying and its effect on the crystallization phenomenon

Amorphous Fe100−x(NbTiTa)x (x = 20, 30 and 40) alloy powders without metalloids were synthesized from commercially available pure elemental powders by mechanical alloying. Microstructure, glass-forming ability, thermal stability and crystallization kinetics of the as-milled powders were analyzed by SEM, XRD, DSC and TEM. Results show that Fe60(NbTiTa)40 has the best glass forming ability with ΔTx = 101 K, which could be explained by appropriate atomic-size mismatch and large negative heat of mixing among main constituent elements. The non-isothermal crystallization kinetics were analyzed. The values of the Avrami exponent (n) suggest that the crystallization of Fe60(NbTiTa)40 and Fe70(NbTiTa)30 amorphous alloy powders is governed by volume diffusion-controlled two-dimensional growth and three-dimensional growth, respectively. The materials obtained in this research provide good candidate for fabricating bulk Fe-based amorphous alloys and related bulk nanocrystalline materials through powder metallurgy methods.