Estimation of crystallite size and lattice strain in nano-sized TiC particle-reinforced 6005A aluminium alloy from X-ray diffraction line broadening

Abstract

Nanostructured AA6005A alloy reinforced with 3 vol% of nano-size TiC particles (ranging in size from 20 to 30 nm) of average crystallite size 55–65 nm was successfully synthesized by high-energy ball milling (HEBM) process for 10 h following a conventional powder metallurgy route. Microstructural changes produced during HEBM, such as crystallite size, lattice strain, lattice deformation stress, and strain energy density of Al lattice were determined using the three simple Williamson–Hall (W–H) models from X-ray diffraction line broadening: uniform deformation model, uniform stress deformation model, and uniform energy density deformation model. The results of estimated average crystallite size by W–H plot methods were compared with TEM results and it is found that both are in good agreement. The three W–H models present a correlation coefficient R2 near the unit indicating the validity of the three models to determine the average crystallite size and the micro-strain of the crystalline network of the nanocomposite obtained and, therefore, indicating that the uniform deformation model is sufficiently accurate. The as-milled unreinforced AA 6005A average crystallite size from well fitted uniform deformation model was 66 nm, therefore, this little difference observed in the calculated average crystallite size of the unreinforced Al alloy and the nanocomposite powders, seems to confirm the hypothesis that the diffuse scattering effect on the broadening of XRD by the addition of nano reinforcing particles is minimum.