Copper Matrix Strengthening in Cu-Al2O3 System by Mechanical Alloying and Milling of Pure Copper and Prealloyed Copper Powders

Abstract

Mechanical alloying of Cu+3wt.% A12O3 powder mixture and milling of pure and prealloyed copper powder with 3.5wt.%Al (CuA13.5) have been performed in planetary ball mill in air up to 2oh. All powders have been then treated in H2 at 400 °C for lh, in order to eliminate formed oxides. Hot pressing was used for compaction (800 °C, 3h, Ar, 35 MPa). The copper matrix strengthening was estimated by microhardness measurements. The microhardness of pure copper powder and prealloyed CuA13.5 powder showed 5 times, and Cu+3% A12O3 powder mixture 4 times greater values respectively, in comparison to the pure untreated copper powder. The strengthening effect in Cu compacts is due to grain refinement and increased dislocation density. The hardness of CuA13.5 powder and Cu+3% A12O3 powder mixture is additionally influenced by of A12O3 dispersoids presence.