Solid state synthesis of Al-based amorphous and nanocrystalline Al-Cu-Nb alloys

An attempt was made to synthesize amorphous and/or nanocrystalline Al-based alloys from elemental powder blends with the stoichiometry Al65Cu35-xNbx (x=5-25 at.% Nb) by high energy planetary ball milling. Microstructure of the milled product at appropriated stages of milling was characterized by X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. The Al65Cu20Nb15 powder blend seems most amenable to solid state amorphization. This amorphous alloy was subjected to controlled heat treatment to develop a two-phase or composite microstructure of nano-aluminide dispersion in amorphous matrix. The results indicate that the present ternary system is akin to our previously reported results on Al-Cu-Ti system in developing completely/partially amorphous and/or nano-aluminide dispersed Al-rich nanocrystalline or amorphous matrix composites by controlled mechanical alloying and/or subsequent annealing