内部酸化したCu-Misch Metal系共晶合金の機械的性質

Abstract

Internal oxidation experiments of Cu+Misch Metal eutectic alloys and Cu+Al solid-solution alloys were carried out using the Rhines packing method at 550 to 850°C for 1 to 100 hr under the oxygen partial pressures of decomposition of Cu2O. Tensile properties of internally oxidized specimens are then measured using MICROMACHINE type Mi-34. Relationships between tensile properties and internal oxidation conditions are measured and discussed with respect to the internal oxidation thickness (=penetration depth: P), assuming that the specimen is composed of two-layered composite materials. Finally, oxidation mechanism of the above-mentioned alloys is analyzed and the activation energies for internal oxidation and diffusion of oxygen, Q1 and Q2 are calculated using the Arrhenius equation. The results obtained are summarized as follows:(1) Proof stress of internally oxidized eutectic alloys (Cu+Misch metal) are decreased with increasing oxidation time and temperature and dispersion-hardening effect could not be observed.(2) Measured proof stress of internally oxidized specimens is in good agreement with the strength calculated based upon two-layered composite materials.(3) Internal oxidation processes are controlled by the diffusion of oxygen and have the activation energies of 40 kcal/mol for Cu+Misch metal alloys and of 53 kcal/mol for Cu+Al alloys.