Microstructure and compressive behavior of Al-Y2O3 nanocomposites prepared by microwave-assisted mechanical alloying

Abstract

In this study, Al–Y2O3 nanocomposites were synthesized via mechanical alloying and microwave-assisted sintering. The effect of different levels of yttrium oxide on the microstructural and mechanical properties of the Al–Y2O3 nanocomposites were investigated. The density of the Al–Y2O3 nanocomposites increased with increasing Y2O3 volume fraction in the aluminum matrix, while the porosity decreased. Scanning electron microscopy analysis of the nanocomposites showed the homogeneous distribution of the Y2O3 nanoparticles in the aluminum matrix. X-ray diffraction analysis revealed the presence of yttria particles in the Al matrix. The mechanical properties of the Al–Y2O3 nanocomposites increased as the addition of yttria reached to 1.5 vol. % and thereafter decreased. The microhardness first increased from 38 Hv to 81 Hv, and then decreased to 74 ± 4 Hv for 1.5 vol. % yttria. The Al–1.5 vol. % Y2O3 nanocomposite exhibited the best ultimate compressive strength and yielded a strength of 359 ± 7 and 111 ± 5 MPa, respectively. The Al–Y2O3 nanocomposites showed higher hardness, yield strength, and compressive strength than the microwave-assisted mechanically alloyed pure Al.