Phase evolution in Al-Ni-(Ti, Nb, Zr) powder blends by mechanical alloying

Abstract

Mechanical alloying of Al-rich Al-Ni-ETM (ETM = Ti, Nb, Zr) elemental powder blends by planetary ball milling yielded amorphous and/or nanocrystalline products after ball milling for suitable duration. Powder samples collected at different stages of ball milling have been examined by X-ray diffraction, differential scanning caloremetry and high-resolution transmission electron microscopy to examine the solid-state phase evolution. Powder blends having nominal composition of Al₈₀Ni₁₀Ti₁₀ and Al₈₀Ni₁₀Nb₁₀ yielded predominantly amorphous products, while the other alloys formed composite microstructures comprising nanaocrystalline and amorphous solid solutions. The amorphous Al₈₀Ni₁₀Ti₁₀ alloy was mixed with different amounts of Al powder, and subjected to warm rolling after consolidation within the Al-cans with or without intermediate annealing for 10 min at 500 K to obtain sheet of 2.5 mm thickness. Notable improvement in mechanical properties has been achieved for the composite sheets in comparison to the pure Al.