Effect of nano-Y2O3 on microstructure and mechanical properties of W-Ni-Cu alloys

The mechanical properties and microstructures of the W-Ni-Cu-Y2O3 alloys with different Y2O3 contents through cold pressing/sintering were investigated. The results demonstrated that the W-Ni-Cu-Y2O3 alloys mainly included the W, (Ni, Cu) and Y2O3 phases. As the Y2O3 content increased, the wrapped W crystals of the W-Ni-Cu-(≤0.4%)Y2O3 alloys were refined. When the Y2O3 content increased to 0.5%, the W crystals began to grow and the pores increased in amount. The densification, the bending strength and the micro-hardness of the W-Ni-Cu-Y2O3 alloys were higher compared to the W-Ni-Cu alloy. The refined and denser microstructure could enhance the mechanical properties of the W-Ni-Cu-Y2O3 alloys, while the Y2O3 aggregation would weaken the corresponding mechanical properties.