The size dependence of microstructure and hardness on the MA powders for the MA-HIP processed Cu-Y₂O₃ dispersion-strengthened alloys

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.