Formation and crystallization of Al–Ni–Ti amorphous alloys

Formation and crystallization behaviors of the Al–Ni–Ti amorphous alloys have been investigated in the present study. Among the amorphous alloy compositions investigated in the present study, only Al87.5Ni10Ti2.5 alloy composition exhibits a good ductility, i.e. 180° bending without fracture, indicating that the ductility of the Al–Ni–Ti amorphous alloys is strongly dependent on the alloy composition. Improved ductility can be obtained only when a few nanometer size Al crystals are embedded in the amorphous matrix. The amorphous Al–Ni–Ti alloys crystallize by either primary crystallization of nanometer-sized fcc-Al phase or by the simultaneous precipitation of fcc-Al and metastable intermetallic compound. The Al–Ni–Ti amorphous alloy showing the bending ductility crystallizes by diffusion-controlled growth of quenched-in Al crystals. On the other hand, the Al–Ni–Ti amorphous alloy without bending ductility crystallizes by diffusion-controlled nucleation and growth process.