Effect of Zr on nanocrystalline Al-4.5 wt.% Cu alloy and its strengthening mechanisms prepared by mechanical alloying

Synthesis and characterization of Al, Al99.5Zr0.5, Al99Zr1 and Al97Zr3 nanostructures developed by high energy ball milling have been carried out in the present study. Mixtures of Aluminium and Zirconium were added to Tungstan carbide vial (Spex Sample Prep) in the desired quantities. The powder mixtures were milled in a Spex 8000 mixer/mill for 500 min to prepare the required nanocrystalline material. Milled powders were compacted in a cylindrical (8 mm dia) tool steel die under an uniaxial applied pressure 99.5 Mpa in a hydraulic pellet press. The compacted milled powders (pellet) were annealed under 2% H-2 (bal. Ar) for 1 h at temperatures from 350 to 500 degrees C and holding at the same temperature for 1 h. The extents of alloying, structural and morphological changes of the nanocrystalline material in the powder form were analyzed and studied using X-ray diffractometer. X-ray diffraction data was analyzed by using X'Pert highscore plus for the calculation of crystallite size and lattice microstrain (%). The Vickers microhardness of all samples was also measured. (C) 2019 Elsevier Ltd. All rights reserved.