Microstructure and mechanical property of Y2O3 dispersion-strengthened copper alloy for fusion reactor prepared by spray drying

Y 2 O 3 dispersion-strengthened copper alloy prepared by mechanical alloying (MA) exhibits a high potential to be used as heat-sink materials in the fusion reactor. However, the feasibility of mass-production of the alloy by MA is still suspicious due to the low efficiency and the introduction of impurity elements. In this work, we prepared Y 2 O 3 dispersion-strengthened copper alloy by spray drying, a method suitable for large-scale production with almost no introduction of impurities. Microstructural investigations found that high-density Y 2 O 3 nanoparticles with the size of ∼9 nm are successfully introduced into the copper matrix by spray drying, which greatly refines the grain and inhibits the recrystallization behavior of the alloy. Moreover, most Y 2 O 3 nanoparticles share a coherent interface with the matrix, and as the Y 2 O 3 particles grow, the coherent interfaces transform into semi-coherent interfaces, with an orientation relationship of (11−1) Cu //(422) Y2O3 . The introduction of Y 2 O 3 nanoparticles greatly enhances the strength of the copper matrix by inhibiting the moving of the dislocations and grain boundaries, and a good combination of hardness (114 HV), strength (326.5 MPa), ductility (8.5 %) and electrical conductivity (85.3 %IACS) was achieved in the Cu-2Y 2 O 3 (wt%) alloy. This work proves the feasibility of introducing nano-scale Y 2 O 3 particles into the copper matrix by spray drying, however, the experimental parameters need to be carefully controlled to prevent agglomeration of Y 2 O 3 dispersoids . Large-scale production of ODS-Cu alloys for the fusion reactor may be realized through spray drying in the future.