Fabrication and characterization of nano-Y 2 O 3 dispersed W-Ni-Nb alloys

Abstract The present research work comprises fabrication of nano Y 2 O 3 ( 79 Ni 10 Nb 10 (Y 2 O 3 ) 1 (alloy A), W 78 Ni 10 Nb 10 (Y 2 O 3 ) 2 (alloy B) and W 72 Ni 10 Nb 15 (Y 2 O 3 ) 3 (alloy C) (all in wt%) by mechanical alloying for 20 h and consolidation by conventional pressureless sintering at 1500 °C for 2 h. The mechanically alloyed powders and consolidated alloys have been characterized by X-ray diffraction, Scanning electron microscopy, Energy dispersive Spectroscopy and Transmission Electron Microscopy. Minimum crystallite size of 20.4 nm has been achieved in alloy C. The formation of NbNi intermetallic phases is evident in the sintered alloys. The bimodality of grains enhances with increases in Y 2 O 3 addition. Maximum % densification of 93.38% and mean hardness of 5.59 GPa has been recorded in alloy C. The wear depth decreases with increase in Y 2 O 3 content upto 2 wt%, however further increase results in enhancement of wear depth and wear loss. Preliminary investigation shows that Y 2 O 3 dispersion upto 1 wt% is effective in providing enhanced oxidation resistance at 900 °C as compared to other alloys.