As the working temperature of aero-engine turbine continues to rise, the inner cavity structure of turbine blades becomes more and more complex. Such hollow air-cooled thin-wall structure requires the very thin wall of turbine blades, while the performance of thin-wall sample may be different compared with standard sample. The stress rupture properties and the fracture character of the second generation directionally solidified alloy DZ406 at 900℃ and 1030℃were studied by using the round bar specimen and three thin-walled specimens with different thicknesses. Results show that the thin-wall effect was very obvious, and under the same test condition, the smaller the wall of the specimen, the more serious the decline of the life. The fracture analysis indicate that the fracture mechanism of DZ406 superalloy by the coalescence of the ‘surface oxidation-crack initiating-crack growth' and ‘inside creep damage'．The relationship between effective stress and oxidation thickness indicates that the surface oxidation had great influence on the durability of the thin-wall specimens.

thin wall effect  /  stress rupture  /  fracture mechanism  /  directionally solidified superalloy