Stress-rupture behavior of a Ni-based Re-containing single crystal superalloy in [001] and [111] orientations at 1100 °C

Turbine blades, due to their intricate geometry, are exposed to multiaxial stresses during operation. Consequently, it is imperative to examine the anisotropy of their stress-rupture behavior across various testing scenarios, particularly under high-temperature conditions. Stress-rupture behavior of a Ni-based single crystal superalloy was investigated under a load varying from 100 MPa to 137 MPa at 1,100 °C for both [001]- and [111]-orientated specimens. Results demonstrate that the rupture behavior of [111]-orientated specimens exhibits obviously higher sensitive to applied stress compared to [001]-orientated specimens. This difference is primarily attributed to the orientation dependent γ′ coarsening behavior and distinct dislocation interactions at γ/γ′ interfaces. In [001]-oriented specimens, plate-like γ/γ′ rafts rapidly form alongside well-developed interfacial dislocation networks, where the γ/γ′ misfit stress dominates the microstructural evolution. In contrast, the [111]-orientated specimens exhibit retained, coarsened γ′ precipitates embedded within the γ matrix, accompanied by poorly developed interfacial dislocation networks.