Fabrication of Al-20Â wt%Si powder using scrap Si by ultra high-energy milling process

► High energy ball milling process has been successfully employed to produce Al-20Si alloy using scrap Si powders. ► Fully finer and homogenous structure could be achieved after 60 min of milling time. ► Si particles were not dissolved but uniformly dispersed in the Al matrix in a milled state. ► The hardness of as-milled Al-20Si powder increased steadily with the increase of milling time. ► Grain size and dispersion strengthening are two mechanisms being responsible for hardness increment.