Freckle Defect Formation near the Casting Interfaces of Directionally Solidified Superalloys

Freckle Defect Formation near the Casting Interfaces of Directionally Solidified Superalloys

Freckle defects usually appear on the surface of castings and industrial ingots during the directional solidification process and most of them are located near the interface between the shell mold and superalloys. Ceramic cores create more interfaces in the directionally solidified (DS) and single crystal (SX) hollow turbine blades. In order to investigate the location of freckle occurrence in ...

ON THE FORMATION OF STRAY GRAINS IN DIRECTIONALLY-SOLIDIFIED NI-BASED SUPERALLOYS WITH VARYING CROSS SECTIONS

Formation of stray grain defects particularly around re-entrant features of the turbine blade airfoils is one of the major problems in directional and single crystal solidification processes. In this work, directional solidification tests of the GTD-111 Ni-based superalloy were conducted at different withdrawal velocities of 3, 6 and 9 mm.min-1 using various stepped cylindrical and cubic design...

Corrosion Resistance of Directionally Solidified Casting Zinc-Aluminum Matrix

A Thermomechanical Fatigue Crack Initiation Model for Directionally-solidified Ni-base Superalloys

Nickel-base superalloys have been used extensively in power generation applications due to their high strength at temperatures up to 1093°C. When the material is subjected to complex mechanical loading superimposed with thermal loading, fatigue interacts with either creep and/or oxidation. Directionallysolidified (DS) materials are often used in place of polycrystalline (PC) materials since the...

Thermomechanical Fatigue Behavior of a Directionally Solidified Ni-Base Superalloy

A continuum crystal plasticity model is used to simulate the material behavior of a directionally solidified Ni-base superalloy, DS GTD-111, in the longitudinal and transverse orientations. Isothermal uniaxial fatigue tests with hold times and creep tests are conducted at temperatures ranging from room temperature (RT) to 1038°C to characterize the deformation response. The constitutive model i...