Effect of pre-strain on oxidation behaviour of nickel-based superalloys in air at 700 degrees C

Abstract

The effect of pre-strain on oxidation behaviour of nickel-based superalloys was analysed using alloys 263 and 740H. Both alloys were subjected to tensile tests followed by oxidation tests at 700 degrees C in air. At higher pre-strain, both alloys exhibited higher oxidation rates and more oxide spallation. Microstructures were examined using various techniques (XRD, SEM, EBSD, and TEM). It was found that the pre-strain accelerated the formation of internal oxides. The defects that formed during the tensile tests apparently acted as oxygen diffusion channels from the oxide/metal interface to the inside of the metal substrate.