Investigations of mechanical, microstructural and tribological properties of Al2024 nanocomposite reinforced by TiO2 nanoparticles

Abstract

Using aluminum metal matrix nanocomposites has recently gained increased attention in the industry due to their high strength and ductility. In this paper, TiO2 nanoparticles in three volume percentages of 0.5, 1 and 1.5 were added to Al2024 alloy using stir casting method. TiO2 nanoparticles were added to the matrix using a novel Powder injection system. The influence of TiO2 content on the mechanical properties, porosity, microstructure and wear resistance of the samples was investigated. SEM images showed that TiO2 nanoparticles uniformly distributed into the metal matrix. This was due to increased wettability of nanoparticles as a result of their controlled injection using the new system. By increasing the percentage of nanoparticles, dendrite size decreased while the hardness of samples increased. At 1.5 volume percentage of nanoparticles the Rockwell B hardness was increased by 31.57%. The elongation of samples was reduced with increasing the nanoparticles content. The sample with 1.5 volume percentage of TiO2 showing 13.8% reduction in elongation compared to the unreinforced sample. Mechanical strength increased with increasing the nanoparticles content until 1% (14.6% higher than the unreinforced sample), while at 1.5% TiO2 was 6.6% higher than the unreinforced sample. The results of the wear test showed that wear resistance significantly increasing with increasing the nanoparticle content and wear mechanism changes from adhesive into abrasive.