Effect of Y₂O₃, TiO₂, ZrO₂ dispersion on oxidation resistance of W–Ni–Nb–Mo alloys

Abstract 1.0 wt.% Y 2 O 3 (alloy S Y ), TiO 2 (alloy S T ), ZrO 2 (alloy S Z ), dispersed 79W–10Ni–5Nb–5Mo (in weight%) alloys have been produced by mechanical alloying with 5:1 ball to powder weight ratio (BPR) for 20 h at 300 rpm in toluene medium. The powders were consolidated by spark plasma sintering at 1,100 °C for 5 min and at 65 MPa pressure. Oxidation study of the consolidated alloys was carried out at 1,000 °C for 10 h to establish the sustainability at elevated temperature. The study shows that alloys S Y, S T exhibit compressive residual stress and alloy S Z evidences tensile residual stress in the oxidized condition. The oxidation rate is significantly lower in alloy S Y due to passive layer formation facilitated by Y 2 O 3 and Ni. The oxidation kinetic study also suggests substantial reduction in rate constant in alloy S Y . The present study also provides interesting inputs regarding development of oxidation resistant alloys for high temperature applications.