Effects of alloyed aluminum and titanium on the oxidation behavior of INCONEL 740 superalloy

An attempt has been made to improve the oxidation resistance of the INCONEL 740 nickel-base superalloy by altering its composition. The effects of aluminum and titanium were studied in particular. Electron microscopy was utilized to characterize and quantify the oxides. The addition of aluminum up to 2.4 wt.% at low titanium contents provides the lowest mass gain. Aluminum internal and grain boundary oxidation, especially at nickel high-angle boundaries, was observed. The surface oxide consists of predominantly Cr2O3. The oxide thickness and defect density increase with the increasing titanium content. (C) 2015 Elsevier B.V. All rights reserved.