Effects of TiO2 powder morphology on the mechanical response of pure magnesium: 1D nanofibers versus 0D nanoparticulates

A novel attempt is made to study and compare the effects of TiO 2 morphology in the form of nanoparticulates and nanofibers on the physical, mechanical and microstructural properties of pure magnesium. Pure magnesium and Mg (1.98 and 2.5) vol. % TiO 2 nanocomposites are synthesized by powder metallurgy technique coupled with microwave sintering followed by hot extrusion. X-Ray diffraction studies of the synthesized magnesium materials indicated that morphology of ultrafine reinforcements play a vital role in modifying the strong basal texture of pure magnesium. The microstructural characterization of Mg–TiO 2 nanocomposites indicated significant grain refinement of pure Mg with TiO 2 nanoparticulates contributing more effectively exhibiting as high as 22% reduction observed with Mg 2.5 vol. % TiO 2 nanocomposite having TiO 2 in the form of nanoparticulates. Under tensile loading, with addition of 1.98 vol. % TiO 2 nanoparticulates and nanofibers, significant improvement in the tensile fracture stain of pure magnesium of ∼14.5% and ∼13.5%, respectively was observed. Further, marginal changes in the tensile strength of pure magnesium by ∼10 MPa was observed with the addition of TiO 2 reinforcements. Under compression loading, among the synthesized magnesium materials, Mg–TiO 2 nanocomposites containing 1.98 vol. % TiO 2 nanofibers exhibited superior strength properties with a maximum 0.2% compressive yield strength and ultimate compressive strength of ∼90 MPa and ∼300 MPa, respectively. Further, decrease in the tension-compression asymmetry values was found to be more significant in Mg–TiO 2 nanocomposites where TiO 2 was used in the fiber form. The results reveal that TiO 2 nanofiber is more effective in improving the overall mechanical performance of pure magnesium.