Oxide Dispersion Strengthened Nickel and Nichrome by Means of the Spray-dispersion Method

Abstract

WO₃, Al₂O₃, ZrO₂, Y₂O₃ or ThO₂-dispersed nickel and nichrome were produced by the "Spray-Dispersion Method", and their mechanical properties were studied. The main results obtained are summarized as follows:
1) The addition of 1.6 pct. niobium as a "controlling element" was effective in lowering the oxide particle size in nickel. The mean diameter of ThO₂ particles in nichel containing 1.6 pct. niobium reached to about 60 nm.
2) 20 pct. of chromium in nickel also decreased the oxide particle size, and the addition of 0.8 pct. niobium in nickel-20 pct. chromium alloy decreased the mean diameter of Al₂O₃ particles to 79 nm.
3) Tensile strengths at room temperature of oxide spray-dispersed nickels increased with the volume fraction of oxide particles and their increments were maintained even at 1073 K. In the case of oxide spray-dispersed nichromes, their incroments of tensile strength at room temperature were small, but those were multiplied at higher temperature.
4) The fine oxide particles contributed to an increase of creep rupture strength, and this tendency became more pronounced toward longer time. 1273 K-1000 h creep rupture strength of 2 vol pct. ThO₂ spray-dispersed nickel and 3.8 vol pct. Al₂O₃ spray-dispersed nichrome, for instance, were 47 Mpa and 19 Mpa, respectively.
5) The oxidation resistance at high temperature of oxide spray-dispersed nickel and nichrome was improved as compared with non-dispersed ones.
From these results, the oxide dispersion strengthened nickel-base heat-resisting alloy has been able to produce by the "Spray-Dispersion Method".