Mechanical alloying of high-strength copper alloys containing TiB2 and Al2O3 dispersoid particles

Abstract

Considerable effort is being devoted to the development of high strength, high conductivity copper alloys both for applications in electronics as well as in aerospace, where the ability to remove heat and to retain a sufficient strength is of critical importance. Examples of such alloys are Cu-Cr-Zr and Cu-Ni-Sn alloys prepared by rapid solidification and by osprey processing (1-6), in situ fabricated fiber-reinforced Cu-Cr, Fe, or Nb composites (7) and mechanically alloyed Cu-bcc metal mixtures (8-10) . the previously examined mechanically alloyed materials showed good strength after consolidation of the milled powders but showed signs of structural instabilities at high temperatures due to coarsening of the dispersed bcc metal particles. The present study examines alloys prepared by milling and consolidating mixtures of copper with other elements which will produce stable compound phases (TiB2 and Al2O3) either during milling or during subsequent annealing. Such dispersed particles should be more resistant to coarsening than the earlier bcc metal particles and should lead to improved strength and stability after high temperature treatments.