Performance of New Dispersion-Precipitation Strengthened Copper-Ceramic Materials made by Mechanical Alloying

摘要

A new high temperature strength, high-conductivity copper base alloys were developed to achieve improved performance. For elevated temperature, dispersion strengthened copper alloys obtained by mechanical alloying( MA) 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 alloying 30 h of milling with 0,5% of ZrB_2 and 1% or 0,5%by vol. of ZrC as fine dispersoids. The alloyed powders were hot consolidated by uniaxial pressing at 923 K and rolling with a 25% of reduction at 1073 K. Consolidated samples were microstructural characterized by X-Ray Diffraction (X-RD), and scanning (SEM) and transmission (TEM) electron microscopy. Hot consolidation process produced fully density MMCs materials with a satisfactory tensile strength as high as 650 MPa and electrical conductivity up to 48 % IACS. The effect of milling process on the microstructure and mechanical properties observed has been related to the pick up of iron, chromium, carbon and oxygen, with Fe-Cr oxicarbides and cuprospinel particles of size about 5-15nm, precipitated during hot consolidation. TEM and SEM revealed that the strength of consolidated metal matrix composites Cu-Zr ceramics is consistent with estimates based on Orowan and Hall-Petch strengthening mechanisms.