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. (paper)