The powder Cu-Al2O3 composites were produced by high-energy milling. Various combinations of particle size and mixtures and approximately constant amount of Al2O3 were used as the starting materials. These powders were separately milled in air for up to 20 h in a planetary ball mill. https://www.bekindtopets.com/special-deal-Accles-Shelvoke-CASH-22-Caliber-Green-3-Grain-Cartridges-1-000-Box-special-save/