Development of Y₂O₃ Dispersion-Strengthened Copper Alloy by Sol-Gel Method

In this study, oxide dispersion-strengthened Cu alloy with a Y₂O₃ content of 1 wt.% was fabricated through citric acid sol-gel synthesis and spark plasma sintering (SPS). The citric acid sol-gel method provides molecular mixing for the preparation of precursor powders, which produces nanoscale and uniformly distributed Y₂O₃ particles in an ultrafine-grained Cu matrix. The effects of nanoscale Y₂O₃ particles on the microstructure, mechanical properties and thermal conductivity of the Cu-1wt.%Y₂O₃ alloy were investigated. The average grain size of the Cu-1wt.%Y₂O₃ alloy is 0.42 μm, while the average particle size of Y₂O₃ is 16.4 nm. The unique microstructure provides excellent mechanical properties with a tensile strength of 572 MPa and a total elongation of 6.4%. After annealing at 800 °C for 1 h, the strength of the alloy does not decrease obviously, showing excellent thermal stability. The thermal conductivity of Cu-1wt.%Y₂O₃ alloy is about 308 Wm^-1K^-1 at room temperature and it decreases with increasing temperature. The refined grain size, high strength and excellent thermal stability of Cu-1wt.%Y₂O₃ alloys can be ascribed to the pinning effects of nanoscale Y₂O₃ particles dispersed in the Cu matrix. The Cu-Y₂O₃ alloys with high strength and high thermal conductivity have potential applications in high thermal load components of fusion reactors.