Performance of new dispersion‐precipitation strengthened copper‐ceramic materials made by mechanical alloying

Abstract

AbstractThe dispersion strengthened copper alloys obtained by mechanical alloying (MA) followed by elevated temperature treatment are attractive due to their excellent combination of thermal and electrical conductivities, strength and microstructural stability. The strengthening of pure copper is provided by mechanical milling with 0.5% of ZrB2 and 1 or 0.5 vol.% of ZrC as fine dispersants. The alloyed powders are hot consolidated by an uniaxial pressing at 923 K and rolling with a 25% of reduction at 1073 K. Microstructural characterization of consolidated samples are by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffraction (XRD). The hot consolidation process resulted in fully dense MMCs materials with an adequate tensile strength as high as 650 MPa and electrical conductivity up to 48% IACS. The effect of milling process on microstructure and mechanical properties observed has been related to the collection of iron, chromium, carbon and oxygen, with Fe‐Cr oxicarbides and cuprospinel particles of size about 5‐15 nm, which are precipitated during hot consolidation. The electron microscopy studies revealed that the strength of consolidated metal matrix composites, Copper‐Zirconium ceramics are consistent with approximations based on Orowan and Hall‐Petch strengthening mechanisms. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)