Development of Nano Y2O3, TiO2, ZrO2 dispersed W-Ni-Nb-Mo alloys by Mechanical

Abstract

W79Ni10Nb5Mo5 based 1.0 wt.% Y2O3 (alloy A), TiO2 (alloy B), ZrO2 (alloy C) oxide dispersed strengthened (ODS) alloys has been synthesized by mechanical alloying with 10:1 and 5:1 ball to powder weight ratio (BPR) for 20 h. The Spark Plasma Sintering of 20 h milled powders has been carried out at 1100, 1200 °C with 65 MPa pressure and 5 min holding time at the sintering temperature. The effect of various dispersions on microstructure, density, mechanical (micro-hardness, compressive strength) and wear properties has been studied. X-ray diffraction (XRD) analysis reveals the occurrence of intermetallics (NiNb, Ni10Zr7, MoNi) which are responsible for improving the strength of the alloys. Minimum grain size for alloy A sintered at 1100°C at 10:1 BPR is .25 µm while for sample sintered at 1200°C at 10:1 BPR is 0.19 µm. Maximum texture intensity has been achieved in alloy A which contributes enhanced strengthening of the alloy. Maximum % relative sintered density of 98.58% is evaluated for alloy A with 10:1 BPR and at 1200 °C. The maximum hardness, compressive strength and %compressive strain at maximum load of 15.54 GPa, 1.98 GPa, 16.2 % respectively and enhanced wear resistance is achieved in alloy A with 10:1 BPR and 1200 °C sintering temperature.