Turbine blades with controlled textures such as directionally solidified and single crystal structures have proven to have much improved ductility and longer thermal and fatigue life. It has been further reported that the benefits of single-crystal over conventionally cast as well as directionally solidified components critically depend on avoiding the introduction of defects, such as stray gra...

Orientation and temperature dependence of yield stress or CRSS (Critical Resolved Shear Stress) and tension/compression anisotropy of the yield stress or CRSS have been shown by Shah and Duhl (1), Heredia and Pope (2), and Miner et al. (3). Tension/compression asymmetry in the yield strength of Ni-based superalloys has been explained in terms of the “core width effect” (4). Shah and Duhl (5) ob...

Decades of research has been focused on improving the high-temperature properties of nickel-based superalloys, an essential class of materials used in the hot section of jet turbine engines, allowing increased engine efficiency and reduced CO2 emissions. Here we introduce a new 'phase-transformation strengthening' mechanism that resists high-temperature creep deformation in nickel-based superal...

Creep deformation and rupture experiments are conducted on samples of the Ni-base superalloy directionally solidified GTD-111 tested at temperatures between 649°C and 982°C and two orientations (longitudinally and transversely oriented). The secondary creep constants are analytically determined from creep deformation experiments. The classical Kachanov–Rabotnov model for tertiary creep damage i...

At the last two Superalloy meetings at Seven Springs, work on the development of thermodynamic modelling tools for application to multi-component Ni-based superalloys has been presented. Such modelling has become quite widespread, providing significant benefit. However, its applicability often falls short from directly providing the information that is actually required and, by itself, cannot b...

The classic Kachanov-Rabotnov isotropic creep damage constitutive model has been used in many situations to predict the creep deformation of high temperature components. Typically, the secondary creep behavior is determined by analytical methods; however, the tertiary creep damage constants are found using a mixture of trial and error and numerical optimization. These methods require substantia...

The fatigue-limit model studied here contains an unknown fatigue limit parameter. Under this model, specimens tested below this fatigue-limit level of stress will never fail. The model also allows the standard deviation of fatigue life to be a function of stress. Researchers can use this model to describe the standard deviation and stress dependence in fatigue data. To illustrate its applicatio...

The effect of solidification behavior on the microstructures and mechanical properties of Ni-Cr-Fe superalloy investment casting is given. Metallographic and image analysis have been used to quantitatively examine the microstructures' evolution. For the parts with the thickness of 3 mm and 24 mm, the volume fraction and maximum equivalent radius of the Laves phase increases from 0.3% to 1.2%, f...

A Ni-based superalloy CMSX-6 was directionally solidified at various drawing speeds (5–20 μm·s−1) and diameters (4 mm, 12 mm) under a 0.5 T weak transverse magnetic field. The results show that the application of a weak transverse magnetic field significantly modified the solidification microstructure. It was found that if the drawing speed was lower than 10 μm·s−1, the magnetic field caused ex...

The most important microstructural processes involved in shock consolidation are identified and illustrated for a nickel-based superalloy and silicon carbide. Interparticle melting, vorticity, voids, and particle fracture are observed. Various energy dissipation processes are identified and analyzed: plastic deformation, interparticle friction, microkmetic energy, defect generation. An analytic...