Effect of Chromium Content on High Temperature Oxidation Resistance and Room Temperature Mechanical Properties of Ni-10Al-xCr-0.6Y₂O₃ Alloy

Alloys of nominal composition Ni-10Al-xCr-0.6Y₂O₃ (x=5, 10, 15, 20, wt%) were prepared by powder metallurgy method. The effects of chromium content on the phase composition, microstructure, high temperature oxidation resistance and mechanical properties at room temperature of the alloys sintered were investigated. The results show that with the increase of chromium content, the voids in the alloys decreased, the relative density increased, and the hardness and bending strength also increased. The alloy containing 20wt% chromium and sintered at 1 270℃ obtained an optimal performance with the hardness of 352 HV and the bending strength of 1 605 MPa. The relatively high content of chromium improved the formation of continuous and dense Al₂O₃ protective film, which reduced the oxidation rate and improved the high temperature oxidation resistance of the alloy.