Stress states in the creep deformed single crystal nickelbase superalloy SC 16

Abstract

The nickelbase superalloy SC 16 is the single crystalline successor of polycrystalline IN 738 LC used as stationary gas turbine blade material. Profiting from the anisotropy of the single crystal structure, an improvement of the creep resistance in [001]-direction at higher temperatures is achieved. Experimental results presented up to now give evidence for different strains parallel and perpendicular to the external load axis and in most recent investigations strain states in different matrix channels could be distinguished. These diffraction experiments, however, were limited in angular resolution and only relative changes between the lattice parameters of the {gamma} and {gamma}{prime} phases could be analyzed. In this paper, a full three dimensional analysis of the strain and stress states in the {gamma}-matrix and in the {gamma}{prime}-particles is presented. The X-ray diffraction experiments were performed using SC 16 samples creep deformed under different external stresses.