Evaluation of Interface between Alumina Dispersion Strengthened Copper Composite and Precipitation Strengthened Copper

Alumina dispersion strengthened copper (ADSC) is nowadays well-researched material. Its properties make it an excellent candidate for use in electrical engineering applications such as material for welding electrodes. The subject of this study was a joint of ADSC and precipitation-strengthened Cu-Cr alloy. ADSC was prepared by powder metallurgy method using Spark Plasma Sintering (SPS). While SPS allows the preparation of low porosity compacts it's limited by the size and shape of compacts it can prepare. This work aimed to prepare different joints between ADSC and Cu-Cr alloy and examine their properties as well as chemical composition and microstructures. Three types of joints were tested. A joint made by pressing ADSC into Cu-Cr sleeve shows the forming of oxides in the joint as well as the hardening of Cu-Cr on the contact surface due to deformation strengthening. Joint made by SPS flash sintering showing the formation of relatively big cavities and the formation of oxides on the materials interface. The in-situ joint was produced using a method where a Cu-Cr sleeve replaced the bottom punch in SPS compaction. The In-situ interface shows very little change in chemical composition and seemingly made a diffusion connection. However, these samples show higher porosity of composite compared to regularly SPS prepared compacts.