Effect of Volume Fraction on the Coarsening of Pb Nanophase in Al-Pb Nanocomposite Alloys Prepared by High Energy Ball Milling

The effect of volume fraction on the coarsening of Pb nanophase in Al-Pb nanocomposite alloys prepared by high energy ball milling has been studied by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The coarsening of Pb nanophase with different volume fractions in Al-Pb nanocomposite alloys follows the cubic growth law even though the size of the constituent phase is in nanometer range. The coarsening rate of Pb nanophase increases distinctly as the volume fraction increases, and the variation of coarsening rate is greater than the theoretical prediction in this composition range. The activation energy for coarsening of Pb nanophase does not vary with volume fraction. The coarsening of Pb nanophase is controlled by grain boundary diffusion for solute atoms in solvent matrix.