Search

To refine the dispersive Y2O3 particles and to explore the optimum Y2O3 content, reducing the Y2O3 addition from 1.5 wt% to 0.5 wt% for Cu6Y sourced Cu-Y2O3 was investigated. It was found that reducing the Y2O3 addition had little influence on the number density, while reducing the size of the Y2O3 particles. Compared with the Y2O3 addition, the nucleation point is expected to be more important for the number density of the Y2O3 by the in-situ fabrication method. Moreover, reducing the Y2O3 addition indeed thinned the prior particle boundaries with O enrichment and contamination, thereby improving the mechanical performance and thermal conductivity. It was calculated that dispersion strengthening made great a contribution to the increment of the yield strength for ODS-Cu. While, the large particles with contamination on the prior particle boundaries induced the dimples and the premature micro-cracks, deteriorating the tensile performance. Therefore, the performance of Cu6Y sourced ODS-Cu can be improved once further reduces the introduction of contamination and suppresses the growth of MA powders during MA process.

Dispersion-strengthened (DS) copper alloys with Y2O3 particles are known as high strength and high thermal conductivity materials having potential for heat sink materials of fusion devices. In the previous study on mechanical alloying (MA) and hot isostatic pressing (HIP) processing of DS-Cu alloys, the MA powders showed various morphology and size distribution which influenced the properties of the MA-HIP samples. In this study, the MA alloyed powders with 3 wt% Y2O3 particles were classified by their size and characterized. The particles ranged from fine particles of under 46 μm to coarse particles of 212 μm over, and a wide particle size distribution was confirmed. The peeled Cu-O fragments from coarser MA powders are the main source of finer grain with 46 μm. The finer grains had oxide-like behavior as microstructural and mechanical properties. On the other hand, the coarser powder having over 212 μm had metal-like behavior as microstructural and mechanical properties. We thought that the classification of the MA powder before HIP process was one of the suitable process to optimize the microstructure and several properties of ODS-Cu alloy.

• ODS-Cu alloy with Y 2 O 3 was successfully produced using the Cu 6 Y compound as the Y source for Y 2 O 3 nano-particles through the MA-HIP process. • Cu 2 O addition on the MA-HIP process promoted to form Y 2 O 3 nano-paritcles with size of 30 nm and number density of 1.7 × 103/μm3. • The Vickers hardness was enhanced by the both the increase of Y 2 O 3 nano-paritcles and the finer sized Cu grain formation. A copper-based material is the recent main trend of advanced heat sink materials for the solid divertor systems, providing an optimal combination of excellent mechanical strength and superior thermal conductivity under severe neutron irradiation environment. In particular, oxide dispersion strengthened Cu (ODS-Cu) alloy with yttrium oxide (Y 2 O 3) nano-particles is one of the promising materials because of the lower influence of the particles on thermal conductivity and the higher resistance to coarsening of the particles due to their thermodynamic stability. The metal Y as the Y 2 O 3 source has been used to fabricate ODS-Cu alloys in the previous work. In this study, we used the Cu 6 Y intermetallic compound as the new Y source material to form Y 2 O 3 particles during mechanical alloying (MA) followed by hot isostatic pressing (HIP) process, and successfully fabricated ODS-Cu alloy with Y 2 O 3 nano-particles using the Cu 6 Y compound. The effects of Cu 2 O addition in this process as the oxidant material were also investigated. Y 2 O 3 nano-particles with typical size of 30 nm were successfully formed into the Cu intra-grains and around grain boundaries, and the density of the Y 2 O 3 nano-particles increased by the Cu 2 O addition. Cu 2 O addition promoted the oxidation of Y from the Cu 6 Y compound, forming Y 2 O 3 nano-particles. [ABSTRACT FROM AUTHOR]