Effect of Y2O3 contents on oxidation resistance at 1150 °C and mechanical properties at room temperature of ODS Ni-20Cr-5Al alloy

Abstract Ni-20Cr-5Al alloy with Y 2 O 3 addition (i.e., 0, 0.2, 0.4, 0.6, 0.8, 1.0, 3.0 and 5.0 wt%) are used to prepare oxide dispersion strengthening (ODS) Ni-based superalloy by powder metallurgy technology. The effect of Y 2 O 3 particles on oxidation resistance at 1150 °C and mechanical properties at room temperature of Ni-20Cr-5Al alloy was investigated. The results show that the oxidation resistance of alloys is improved when the content of Y 2 O 3 is under 0.6 wt%. The oxidation resistance of alloys decreased obviously when the content of Y 2 O 3 is over 0.8 wt%. It is due to the small amount of Y 2 O 3 is conducive to form stable oxide scale, and improves the adhesion of oxide scale and matrix. While Y 2 O 3 content is too high, it is easier to result in segregation of Y 2 O 3 , which create defects in matrix and decrease exfoliation resistance of oxide scale. Continuous and compact Al 2 O 3 oxide scale can effectively protect matrix. The relative density of alloys can be significantly increased with Y 2 O 3 addition which is 0.2–0.6 wt%, it’s speculated that distribution of Y 2 O 3 in matrix is benefit to promote rearrangement and densification of grains during process of sintering. While Y 2 O 3 content is more than 0.8 wt%, Y 2 O 3 will hinder viscous flow and reduce relative density due to its strong thermal stability.