The Study of Superalloy Oxide Scale Stress

Abstract

Stress is the essential factor to cause surface oxide scale exfoliation to lose oxidation resistance for superalloys. In this paper, a new kind of experimental technique, rectangle wedge slice moment method, was studied to test in situ the real time oxide scale stress of ferro based superalloy GH2036 during high temperature oxidation. Having been oxidated for 10 hours at 800°C, the oxide scale stress σ versus time t was regressed to follow the power function σ=179.1745t 0.0714 . The scale stress goes up with oxidation time, but its gain decreases, reducing the exfoliation tendency and benefitting the protecting. New born oxides growing at the interface of matrix and scales generate the oxide scale stress. More oxides bring thicker scales, bigger stress and higher oxidation resistance.