Mechanical properties of Al7075 alloy with nano-ceramic oxide dispersion synthesized by mechanical milling and consolidated by equal channel angular pressing

Abstract

An Al-alloy matrix composite with a dispersion of nano-TiO2 has been sysnthesized in powder form b mechanical milling of pre-alloyed Al7075 alloy and nano-TiO2 powder blend. XRD and Tem analyses of the milled powder confirm the particle/crystallite size in nanometer range. The composite powder was consolidated by equal channel angular pressing (ECAP) at ambient temperature and 473 K at speed of 5mm/min. Microstructural analysis of consolidated compacts compacts of Al7075 alloy with nano-TiO2 dispers-ion was carried out using both scanning and transmission electron microscopy. The compacts prepared by ECAP possess reasonably good density (90% of theoretical density), excellent hardness (3.72 GPa/344 VHN) and high stiffness (Young’s modulus of 92 GPa). Furthermore, the compacts cons-olidated by 4 ECAP passes at 473 K exhibit, beside the highest density, an extremely high compressive stren-gth (1.7 GPa). Conspicuously the above properties are independent of structural orientation as texture analysis shows almost random texture even after ECAP consolidation.