Fabrication of Oxide Dispersion Strengthened Copper Alloy Powders by Atmosphere-Controlled Gas Atomization

In order to develop a new oxide-dispersion strengthened Cu alloy for heat sinks of fusion helical reactors, Cu alloy powders containing Ti, Fe and Y were prepared by atmosphere controlled gas atomization, and the effect of oxygen was investigated. The microstructure of the Cu alloy powder had a typical solidification structure regardless of the alloying element and gas species. The Fe atom was uniformly solid-soluted in the matrix, while the Ti and Y atoms were swept out from the matrix to the grain boundaries and particle surfaces during solidification. The average particle size and aspect ratio of the obtained powders decreased with the use of the N2+O2 gas mixture. This is due to the lower surface tension of Cu in the oxygen atmosphere, suggesting that the frequency of the strip breakage stage in the gas atomization process was suppressed due to the formation of oxide film on the particle surface.