Influence of Cu-Y compound content on the microstructure of Cu-Y₂O₃ dispersion strengthened alloys synthesized by MA and HIP process

Oxide Dispersion Strengthened Cu alloy (ODS-Cu) with Y₂O₃ has great application potential in the field of fusion. In the previous fabrication method by adding metal Y as the source of Y₂O₃, severe sticking occurred during mechanical alloying (MA) and huge Y particles still remained after MA. Considering that Cu-Y compounds are more brittle than pure Y, which is expected to resolve the sticking issue, and have lower Y enrichment, which will make it easier to form uniform Y distribution, ODS-Cu with various content of Y by adding Cu₂Y or Cu₆Y were fabricated through MA and Hot isostatic pressing (HIP) process. A comparative analysis was made for the samples with addition of Cu₂Y and Cu₆Y. The results showed that, compared with Cu₂Y, Cu₆Y is easier to form uniform Y distribution. The most likely reason is that the Cu₆Y is more brittle and less Y abundance than Cu₂Y. The sample with 0.39 wt% Y with Cu₆Y addition has the highest Vickers hardness, possibly because of solution strengthening caused by higher content of interstitial O, and better electrical conductivity than the sample with 1.19 wt% Y with Cu₆Y possibly because of the more uniform formation of Y₂O₃ and the absence of precipitation phases. (author)