Oxidation Behavior of Pre-Strained Polycrystalline NiAl-Based Superalloy.

The harsh service environment of aeroengine hot-end components requires superalloys possessing excellent antioxidant properties. This study investigated the effect of pre-strain on the oxidation behavior of polycrystalline NiAl-based superalloys. The growth behaviors of oxidation products were analyzed by scanning electron microscope, transmission electron microscope, X-ray Photoelectron Spectroscopy and Raman spectroscopy. The results indicated that the 5% pre-strained alloys exhibited lower mass gain, shallower oxidation depth and more compact oxide film structures compared to the original alloy. This is mainly attributed to the formation of rapid diffusion paths for Al atoms diffusing to the surface under 5% pre-strain, which promotes the faster formation of protective AlO film while continuing to increase the pre-strain to 25% results in less protective transient oxidation behavior being aggravated due to the increase in dislocation density within the alloy, which prevents the timely formation of the protective AlO film, resulting in uneven oxidation behavior on the alloy.