Posted 28 Dec 2010 19:09
Cr2O3 prepared by internal oxidation dispersion strengthened copper composite process the following main parts: ?Cu-Cr alloy powders: Cu-Cr alloy smelting, the use of nitrogen gas atomization or water atomization, the melt powdered ; ?into oxygen source: the made of Cu-Cr alloy powder mixed with the oxygen source; ?Preparation of internal oxidized powder: The powder mixture is heated to high temperature and control the partial pressure of oxygen, because Cu is easily produced than Cr oxide, the Cr was first oxidized to Cr2O3; ?powder metallurgy internal oxidation: the oxidation of the powder by forming, sintering, extrusion, etc. made of the required profiles. Cr2O3 dispersion strengthened copper composite material can maintain a high electrical conductivity, thermal conductivity, also has high strength and hardness, which is the presence of Cr2O3 particles are inseparable. As a strengthening phase dispersed Cu composite Cr2O3 on the performance of the major contributions in: (1) Cr2O3 particles as a dislocation source, an increase of dislocation density, the strength of the composite was improved. (2) Cr2O3 particles impede the dislocation in the grain sector, the sub-grain boundary movement in order to hinder the growth of grains, the dislocation pinning played a role. Orowan strengthening model (Orowan) mechanism: Cr2O3 particles encountered in the dislocation line, can not directly, in the role of external forces, the dislocation line will be bent around the Cr2O3 particles, and finally left in the Cr2O3 particles around a bit dislocation loops and make way for the wrong pass. Bend the dislocation line will increase the impact zone of dislocation lattice distortion energy, which increases the resistance movement of the dislocation line, the sliding resistance increases, thus increasing the composite strength. (3) Cr2O3 particles can inhibit the presence of dynamic recrystallization, dispersion strengthened copper composite materials not only in the Cr2O3 particles pinning the dislocation, but also pinning grain boundaries, subgrain boundaries, materials, work in the copper melting point, the nail bundle pinning the grain boundary dislocation than the strengthening effect of the material even more. Preparation of internal oxidation is currently Cr2O3 progress of dispersion strengthened copper composite materials maximum, one of the most active. In the future, including the preparation of Cr2O3 oxide dispersion strengthened copper composite materials research focused on the following aspects: (1) optimize the oxidation process. Superior performance in ensuring the products under the premise of simplifying the preparation process and reduce costs, to further explore the microscopic mechanisms of internal oxidation, internal oxidation of the media and optimize the process parameters of internal oxidation. (2) microstructure. Cr2O3 particles are dispersed, of different size of Cr2O3 and copper-based interface structure, the design process is also important. (3) improve the mechanical properties. Particle size of Cr2O3, concentration and distribution of copper-based composites at room temperature strength, high temperature strength, resistance to softening temperature, the recrystallization temperature, composition and optimization of guidance material to improve performance are of great significance. (4) trend of industrialization. Optimize process performance, applied to actual production, the Cr2O3 dispersion strengthened copper composite materials for new areas, and the implementation of industrial production, to improve the effectiveness of industry-related industries.