Effect of Dopant Element on the Strength and Reliability of Ni-Base Superalloy at High Temperatures

2012 ◽  
Author(s):  
Tomohiro Sano ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
High Temperatures ◽  
Anisotropic Diffusion ◽  
Axial Strain ◽  
Face Centered Cubic ◽  
High Temperature Materials ◽  
Directional Coarsening ◽  
Face Centered ◽  
Dopant Element ◽  
Base Superalloy

In order to assure the reliability of advanced gas turbine systems, it is very important to evaluate the damage of high temperature materials such as Ni-base superalloys under creep and fatigue conditions quantitatively. The mechanism of the directional coarsening (rafting) of the γ′ phase (Ni3Al) of Ni-base superalloys under uni-axial strain at high temperatures was analyzed by molecular dynamics (MD) analysis. The strain-induced anisotropic diffusion of Al atoms perpendicular to the interface between the γ′ phase and the γ phase (Ni-matrix) was observed clearly at a Ni(001)/Ni3Al(001) interface. The strain-induced anisotropic diffusion was validated by the experiment using the stacked thin film structures with the (001) face-centered cubic (FCC) interface. The reduction of the diffusion of Al atoms perpendicular to the interface is thus, effective for improving the creep and fatigue resistance of the alloy. It was found by MD analysis that palladium was one of the most effective elements that restrain Al atoms from moving around the interface under the applied stress. The presence of the interaction between the different dopant elements was also clarified.

High Temperature Damage of Ni-Base Superalloy Caused by the Change of Microtexture due to the Strain-Induced Anisotropic Diffusion of Component Elements

2011 ◽  
Author(s):  
Hideo Miura ◽  
Ken Suzuki ◽  
Yamato Sasaki ◽  
Tomohiro Sano ◽  
Naokazu Murata
Keyword(s):  
High Temperature ◽  
Anisotropic Diffusion ◽  
Axial Strain ◽  
Creep Damage ◽  
Face Centered Cubic ◽  
Directional Coarsening ◽  
Damage Process ◽  
Temperature Damage ◽  
Face Centered ◽  
Base Superalloy

In order to assure the reliability of advanced gas turbine systems, it is very important to evaluate the damage of high temperature materials such as Ni-base superalloys under creep and fatigue conditions quantitatively. Since the micro texture of the gamma-prime (γ′) phase was found to vary during the creep damage process, it is possible, therefore, to evaluate the creep damage of this material quantitatively by measuring the change of the micro texture. The mechanism of the directional coarsening of γ′ phasesof Ni-base superalloy under uni-axial strain at high temperatures, which is called rafting, was analyzed by using molecular dynamics (MD) analysis. The stress-induced anisotropic diffusion of Al atoms perpendicular to the finely dispersed γ/γ′ interface in the superalloy was observed clearly in a Ni(001)/Ni3Al(001) interface structure. The stress-induced anisotropic diffusion was validated by experiment using the stacked thin films structures which consisted of the (001) face-centered cubic (FCC) interface. The reduction of the diffusion of Al atoms perpendicular to the interface is thus, effective for improving the creep and fatigue resistance of the alloy. It was also found by MD analysis that the dopant elements in the superalloy also affected the strain-induced diffusion of Al atoms. Both palladium and tantalum were effective elements which restrain Al atoms from moving around the interface under the applied stress, while titanium and tungsten accelerated the strain-induced anisotropic diffusion, and thus, the rafting phenomenon.

High Temperature Damages of Ni-Base-Superalloy Caused by the Change of Nanotexture Due to Strain-Induced Anisotropic Diffusion

2010 ◽  
Author(s):  
Yamato Sasaki ◽  
Hiroyuki Itoh ◽  
Naokazu Murata ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
High Temperature ◽  
Anisotropic Diffusion ◽  
Axial Strain ◽  
Creep Damage ◽  
Face Centered Cubic ◽  
Gamma Prime ◽  
Directional Coarsening ◽  
Damage Process ◽  
Face Centered ◽  
Base Superalloy

In order to assure the reliability of advanced gas turbine systems, it is very important to evaluate the damage of high temperature materials such as Ni-base superalloys under creep and fatigue conditions quantitatively. Since the micro texture of the gamma-prime (γ′) phase was found to vary during the creep damage process, it is possible, therefore, to evaluate the creep damage of this material quantitatively by measuring the change of the micro texture. The mechanism of the directional coarsening of γ′ phases (rafting) of Ni-base superalloy under an uni-axial strain at high temperatures was analyzed by molecular dynamics (MD) analysis. The stress-induced anisotropic diffusion of Al atoms perpendicular to the initially finely dispersed γ/γ′ interface in the superalloy crystal was observed clearly in a Ni(001)/Ni3Al(001) interface structure. The stress-induced anisotropic diffusion was validated by experiment using the stacked thin films structures which consisted of the (001) face-centered cubic (FCC) interface. The reduction of the diffusion of Al atoms perpendicular to the interface is thus, effective for improving the creep and fatigue resistance of the alloy. It was also found by MD analysis that the dopant elements in the superalloy also affected the strain-induced diffusion of Al atoms. Palladium was one of the most effective elements which restrain Al atoms from moving around the interface under the applied stress.

scholarly journals Creep and Fatigue Damages of Ni-Base-Superalloy Caused by Strain-Induced Anisotropic Diffusion of Component Elements

2009 ◽  
Vol 417-418 ◽  
pp. 261-264
Author(s):  
Hideo Miura ◽  
Ken Suzuki ◽  
Hiroyuki Ito ◽  
Tatsuya Inoue
Keyword(s):  
Molecular Dynamics ◽  
Fatigue Resistance ◽  
Anisotropic Diffusion ◽  
Axial Strain ◽  
Interface Structure ◽  
Directional Coarsening ◽  
Base Superalloy

The mechanism of the directional coarsening of ' phases (rafting) of Ni-base superalloy under an uni-axial strain was analyzed by molecular dynamics (MD) analysis. The stress-induced anisotropic diffusion of Al atoms perpendicular to the interface was observed clearly in a Ni(001)/Ni3Al(001) interface structure, The reduction of the diffusion of Al atoms perpendicular to the interface is thus, effective for improving the creep and fatigue resistance of the alloy. It was also found that the dopant elements in the superalloy also affected the strain-induced diffusion of Al atoms. Pd was one of the most effective elements which restrain Al atoms from moving around the interface.

Electron diffraction detection of ordliking in annealed PbTe thin film

1990 ◽  
Vol 48 (4) ◽  
pp. 1018-1019
Author(s):  
Karimat El-Sayed
Keyword(s):  
Thin Film ◽  
Electron Diffraction ◽  
Lead Telluride ◽  
Structural Basis ◽  
Face Centered Cubic ◽  
X Ray ◽  
Polycrystalline Thin Films ◽  
Stage Process ◽  
Diffraction Patterns ◽  
Face Centered

Lead telluride is an important semiconductor of many applications. Many Investigators showed that there are anamolous descripancies in most of the electrophysical properties of PbTe polycrystalline thin films on annealing. X-Ray and electron diffraction studies are being undertaken in the present work in order to explain the cause of this anamolous behaviour.Figures 1-3 show the electron diffraction of the unheated, heated in air at 100°C and heated in air at 250°C respectively of a 300°A polycrystalline PbTe thin film. It can be seen that Fig. 1 is a typical [100] projection of a face centered cubic with unmixed (hkl) indices. Fig. 2 shows the appearance of faint superlattice reflections having mixed (hkl) indices. Fig. 3 shows the disappearance of thf superlattice reflections and the appearance of polycrystalline PbO phase superimposed on the [l00] PbTe diffraction patterns. The mechanism of this three stage process can be explained on structural basis as follows :

Interface structure of face-centered-cubic-Ti thin film grown on 6H–SiC substrate

2000 ◽  
Vol 15 (10) ◽  
pp. 2121-2124 ◽  
Author(s):  
Y. Sugawara ◽  
N. Shibata ◽  
S. Hara ◽  
Y. Ikuhara
Keyword(s):  
Thin Film ◽  
Orientation Relationship ◽  
High Resolution Electron Microscopy ◽  
Electron Beam Evaporation ◽  
Face Centered Cubic ◽  
High Adhesion ◽  
Resolution Electron ◽  
Face Centered ◽  
Relationship Of ◽  
High Degree

A titanium thin film was deposited on the flat (0001) face of a 6H–SiC by electron beam evaporation at room temperature in a vacuum of 5.1 × 10−8 Pa. The Ti film was epitaxially grown on the surface, and the interface between Ti and SiC was characterized by high-resolution electron microscopy. It was found that the structure of the deposited titanium is face-centered cubic (fcc), although bulk titanium metal usually has a hexagonal close-packed or body-centered cubic crystal structure. We believe that the unusual fcc structure of Ti thin film is due to the high adhesion of the film to the substrate and the high degree of coherency between them. The orientation relationship of the fcc-Ti/6H–SiC interface was (111)fcc-Ti//(0001)6H–SiC and [110]fcc-Ti//[1120]6H−SiC. Preliminary calculations indicate that this orientation relationship maximizes the lattice coherency across the interface.

Electrodeposition of CuI Thin Film for Perovskite Solar Cells

2020 ◽  
Vol 979 ◽  
pp. 180-184
Author(s):  
I. Karuppusamy ◽  
K. Ramachandran ◽  
S. Karuppuchamy
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Solar Cells ◽  
Applied Voltage ◽  
Perovskite Solar Cells ◽  
Face Centered Cubic ◽  
Applied Potential ◽  
Cathodic Electrodeposition ◽  
Cubic Structure ◽  
Face Centered

The CuI thin film has been successfully prepared by using cathodic electrodeposition method. The synthesized film was characterized using advanced techniques such as XRD, SEM-EDX and UV measurements. The films are crystallized in face centered cubic structure. The crystallinity is increasing for the applied potential of-0.3 V and the crystallinity deteriorates on increasing the potential above - 0.3 V. It was also observed that the applied voltage plays an important role. Homogeneously distributed triangular faceted morphology was observed from SEM. This is consistent with the result of XRD that electrodeposited CuI thin films grow preferential orientation along the (111) crystal plane.

Effect of Annealing Conditions on Microstructure Evolution of NiMnFeGa Shape Memory Thin Film

2010 ◽  
Vol 150-151 ◽  
pp. 1745-1749
Author(s):  
Hai Bo Wang ◽  
Li Ma ◽  
Wei Cai
Keyword(s):  
Thin Film ◽  
Shape Memory ◽  
Microstructure Evolution ◽  
Face Centered Cubic ◽  
Free Standing ◽  
Annealing Conditions ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Face Centered ◽  
Ferromagnetic Shape Memory

The microstructure evolution of sputtered polycrystalline Ni54.75Mn13.25Fe7Ga25 ferromagnetic shape memory thin film annealed under different conditions is studied. Microstructure of different annealed films was studied using Transmission Electron Microscope (TEM) and corresponding selected area electron diffraction (SAED) patterns. The result shows that in the microstructure of as-deposited Ni54.75Mn13.25Fe7Ga25 free-standing film, after annealed at 1073 K for different time, the crystalline grain grows up with the increase of the annealing time. By analysis of the SAED patterns, the structure of the thin films change from face-centered cubic austenite to orthorhombic structure martensite compared between the film annealed at 1073 K for 10 mins, 1hr, 4 hrs, and 24 hrs respectively. It indicated that the heat treatment is an effective method of crystallizing behavior for the thin film.

Optical Constants Retrieval from a Thin Film at Elevated Temperatures Using Emittance

2021 ◽  
Author(s):  
Jui-Yung Chang ◽  
Yi-Hua Yang ◽  
Vikas Yadav ◽  
Yu-Bin Chen
Keyword(s):  
Thin Film ◽  
Refractive Index ◽  
Thermal Radiation ◽  
Optical Constants ◽  
Elevated Temperatures ◽  
Emission Angle ◽  
Face Centered Cubic ◽  
Hexagonal Close Packed ◽  
Phase Temperature ◽  
Face Centered

Abstract Refractive index and extinction coefficient (optical constants) are essential in photonic design and thermal radiation utilization. These constants vary with the material phase, temperature, wavelength, and subject dimension. Precisely retrieving these constants of a thin film is thus challenging at elevated temperatures. To tackle this challenge, a methodology for retrieval using emittance at different emission angle θ has been developed here. The method contains four steps and takes advantages of an emissometry. The method is firstly validated using simulation and then demonstrates its feasibility by retrieving optical constants of a phase change germanium-antimony-tellurium (Ge2Sb2Te5, GST) film. Emittance from samples at 100°C, 200°C, 300°C, and 400°C is measured at θ = 0°, 15°, and 30°. The spectral range of retrieval covers from 4 μm to 18 μm where thermal radiation dominates. The investigated film phase considers amorphous, face-centered cubic (FCC), and hexagonal close packed (HCP). The retrieved constants exhibit temperature and substrate independence, but they show up significant phase reliance.

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