Synthesis and Characterization of Al-4.5%Cu Alloy Powder Using Mechanical Alloying

Abstract

The present work aims to improve the mechanical properties of Duralumin (Al-4.5 wt. % Cu) alloy produced by mechanical alloying and consolidated using conventional isotactic hydraulic compressor. A uniform dispersion of SiC and TiO2 reinforcements tends to improve the mechanical properties of the present alloys. The current alloys show xtraordinary hardness values which are 1-1.5 times higher than the conventional duralumin alloys. For this purpose, pure elemental powders of Al and Cu were blended and milled in a planetary ball mill and sintered at 550°C for 1 hour in Argon atmosphere. XRD and SEM of samples collected at different stages during milling and after sintering were done to determine the phase evolution and microstructural morphology of the current alloys. The crystallite size, lattice strain and lattice parameters were analyzed by Williamson-Hall method. The crystallite size decreases rapidly up to 7 hours of milling and becomes almost constant with further milling. Addition of SiC (5 and 10 vol. %) and TiO2 (5 and 10 vol. %) as reinforcements in the matrix improves the hardness. Addition of SiC reinforcement leads to better dispersion than TiO2 as evident from the hardness values. This is due to the higher modulus of elasticity of SiC which is almost double than that of TiO2.