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

Abstract

An attempt was made to synthesize amorphous and/or nanocrystalline Al-based alloys from elemental powder blends with the stoichiometry Al₆₅Cu_35-xNb_x (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.