Thickness influence on creep properties for Ni-based superalloy M247LC SX

The influence of specimen thickness on creep behavior of coated and uncoated specimens was investigated. Creep experiments were carried out on the single crystal Ni-base superalloy M247LC SX at 980 °C and 1100 °C. Tests were performed at different stress levels for 0.3 mm and 1.0 mm flat specimens in vacuum and ambient air. ease in creep strength with decreasing thickness was observed. Aluminized specimens showed less scatter in creep behavior in terms of both, rupture times and minimum creep rates. If only the initial two-phase area is considered (without interdiffusion zone and coating layer) the influence of specimen thickness on creep behavior were found to be negligible. sults show, that for turbine blade design the influence of wall thickness has to be considered. Thin-walled structures (below 1.0 mm) should be aluminized in order to reduce scatter in material behavior and to minimize the influence of oxidation on matrix/γ′-microstructure in order to form γ′ reduced or γ′ depleted zones.