Effect of shot-peening on the oxidation of alloy 800H exposed to supercritical water and cyclic oxidation

Incoloy alloy 800H is an important engineering material for a variety of applications. However, the extensive oxide exfoliation of this material may suppress its life-span and potential applications. This paper presents the effect of shot-peening on the oxidation behavior of alloy 800H following exposure to supercritical water at 500 degrees C and 25 MPa and cyclic oxidation at 850 degrees C in air. The analysis indicates that the shot-peening processing produced an ultrafine-grained surface resulting in an enhanced Cr diffusivity to form Cr and Cr-rich oxides. The shot-peening processing is an effective approach, which not only improved oxidation resistance, but also mitigated oxide exfoliation on alloy 800H. (C) 2008 Elsevier Ltd. All rights reserved.