Cu-ThO₂,Cu-Al₂O₃,Cu-W分散強化方焼結合金の強度

抄録

The influences of the kind of dispersed phase on the mechanical properties of dispersion stregthened copper alloys were discussed. The specimens were prepared by ball mill mixing of electrolytic copper powder (-325 mesh) with dispersed powder, followed by compacting, sintering, hot extruding and cold drawing, and annealed at 600°C for 1hr in vacuum before testing. Thoria, alumina and tungsten powders were used for the dispersion particle. For comparison, two kinds of pure copper were prepared, -one was of the sintered electrolytic copper powder compact and the other of the ingot of vacuum melted cathode copper. The experimental results showed that the strength of dispersion strengthened alloys could be determined by the interfacial energy between copper matrix and dispersed phase, the adhesion of the dispersed phase to the matrix, the degree of dispersion of particles in matrix, and the thermal stability of the dispersed phase. Copper-thoria alloy was the most excellent among the three dispersion strengthened alloys.
The grain size of the metal matrix of the dispersion strengthened alloy was progressively smaller with an increase in the amount of dispersed phase. In the case of pure metal or solid solution alloy, it has been shown in general that the smaller the grain size, the higher the strength was. For the dispersion strengthened alloy, the strength was affected much more by dispersion strengthening mechanism of dispersed particles themselves than by the grain size of the matrix.