Characterisation of the Structure of Single-Crystal Nickel-Base Superalloys

2010 ◽  
Vol 638-642 ◽  
pp. 2227-2232 ◽  
Author(s):  
Alexander Epishin ◽  
Thomas Link ◽  
Udo Brückner
Keyword(s):  
Single Crystal ◽  
Dendritic Structure ◽  
Experimental Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nickel Base Superalloys ◽  
Nickel Base ◽  
Kinetics Of ◽  
Morphology Changes ◽  
Sem Investigation

New experimental methods developed by the authors for characterisation of the structure of single-crystal nickel-base superalloys are presented: X-ray diffraction at defined areas of the dendritic structure, none destructive SEM investigation of ’-morphology changes for different creep stresses and times with one specimen, and high resolution SEM investigations of dislocations in the ’-interfaces. Application of these techniques allowed to obtain new results, e.g. about the mosaicity of dendritic subgrains, distribution of the ’-misfit within a single dendrite and kinetics of rafting during creep in the superalloy CMSX-4 in wide temperature and stress ranges.

A Powder Diffractometry Study of γ'-Phase Formation

1991 ◽  
Vol 6 (2) ◽  
pp. 66-69
Author(s):  
S. Ariely ◽  
G. Kimmel ◽  
S. F. Dirnfeld ◽  
M. Bamberger ◽  
B. Prinz
Keyword(s):  
Phase Formation ◽  
Early Stage ◽  
Pure Nickel ◽  
X Ray Diffraction ◽  
Type Alloy ◽  
Optimal Program ◽  
X Ray ◽  
Nickel Base ◽  
Kinetics Of ◽  
Base Superalloy

AbstractThe kinetics of γ'-phase formation in a Ni-base superalloy were studied. The data (pairs of cps and 2θ) were processed by the deconvolution program (Wiedemann, Unnam and Clark, 1987), which was rewritten in FORTRAN and installed on an IBM/VM and a VAX/VMS host computer. Optimal program parameters were found. Pure nickel was used as a standard. The only evidence obtained from the raw data is that the early stage of the aging process is accompanied by broadening. Deconvolution resolved the peaks into three kinds of diffraction lines: Ni(γ), precipitate (γ'), and undefined lines which have been interpreted as satellites. The results show that our X-ray diffraction lines are composed of the main diffraction lines of nickel-base A1 type alloy and additive satellites. In an advanced stage of aging the satellites assume the typical diffraction pattern of γ' phase.

In Situ Imaging of High Cycle Fatigue Crack Growth in Single Crystal Nickel-Base Superalloys by Synchrotron X-Radiation

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Liu Liu ◽  
Naji S. Husseini ◽  
Christopher J. Torbet ◽  
Divine P. Kumah ◽  
Roy Clarke ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Single Crystal ◽  
Real Time ◽  
Crack Growth ◽  
Fatigue Cracks ◽  
X Ray ◽  
Ultrasonic Fatigue ◽  
Nickel Base Superalloys ◽  
Nickel Base

A novel X-ray synchrotron radiation approach is described for real-time imaging of the initiation and growth of fatigue cracks during ultrasonic fatigue (f=20kHz). We report here on new insights on single crystal nickel-base superalloys gained with this approach. A portable ultrasonic fatigue instrument has been designed that can be installed at a high-brilliance X-ray beamline. With a load line and fatigue specimen configuration, this instrument produces stable fatigue crack propagation for specimens as thin as 150μm. The in situ cyclic loading/imaging system has been used initially to image real-time crystallographic fatigue and crack growth under positive mean axial stress in the turbine blade alloy CMSX-4.

Highly luminescent crystals of a novel linear π-conjugated thiophene–phenylene co-oligomer with a benzothiadiazole fragment

2019 ◽  
Vol 75 (6) ◽  
pp. 1076-1085 ◽  
Author(s):  
Valery A. Postnikov ◽  
Nataliya I. Sorokina ◽  
Artem A. Kulishov ◽  
Maria S. Lyasnikova ◽  
Vadim V. Grebenev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Liquid Crystalline ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
Growth From Solutions ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Kinetics Of ◽  
Thermal Stability Of

The synthesis, growth from solutions and structure of crystals of a new linear thiophene–phenylene co-oligomer with a central benzothiadiazole fragment with a conjugated core, (TMS-2T-Ph)2-BTD, are presented. Single-crystal samples in the form of needles with a length of up to 7 mm were grown and their crystal structure was determined at 85 K and 293 K using single-crystal X-ray diffraction. The conformational differences between the crystal structures are insignificant. The parameters of melting and liquid crystalline phase transitions of (TMS-2T-Ph)2-BTD were established using differential scanning calorimetry and the thermal stability of the crystals was investigated using thermogravimetric analysis. The optical absorption and photoluminescence spectra of the solutions and crystals of (TMS-2T-Ph)2-BTD were obtained, and the kinetics of their photodegradation under the action of UV radiation were studied.

Oxidation Behavior of Rh-xTi Refractory Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 721-724
Author(s):  
Rabindra Mahapatra ◽  
A.W. Davis
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Complex Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Refractory Alloys ◽  
Nickel Base Superalloys ◽  
Nickel Base ◽  
Xrd Techniques ◽  
Lower Oxidation

In this paper we report the oxidation behavior of Rh-xTi (x = 15 & 20 atomic percent) alloys isothermally exposed in air between 1000 and 1300 oC up to a period of 312 hours. The weight gain of arc-melted Rh-15Ti and Rh-20Ti alloys as a function of time was monitored. Results indicate that the oxidation resistance of Rh-15Ti and Rh-20Ti alloys at 1000 and 11000 C is similar to that of advanced nickel-base superalloys. However, these alloys show excellent oxidation resistance beyond the operational limit for nickel-base superalloys. Optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) techniques were used to study the microstructure and morphology of the oxides. These alloys oxidize by forming TiO2 and Rh2O3 complex oxides. The Rh-20Ti alloys displayed lower oxidation resistance than Rh-15Ti alloys.

scholarly journals Lattice Misfit of High Refractory Ruthenium Containing Nickel-Base Superalloys

2011 ◽  
Vol 278 ◽  
pp. 60-65 ◽  
Author(s):  
Steffen Neumeier ◽  
J. Ang ◽  
R.A. Hobbs ◽  
Catherine M.F. Rae ◽  
Howard J. Stone
Keyword(s):  
Lattice Misfit ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Matrix ◽  
Coherency Stress ◽  
Matrix Lattice ◽  
Chemical Segregation ◽  
Nickel Base Superalloys ◽  
Nickel Base

The influence of Ru, Co, Mo and W on the lattice misfit of eight highly alloyed Re containing single crystal nickel-base superalloys was investigated. High resolution X-ray diffraction (XRD) was used to relate the elemental partitioning behavior and the Vegard coefficients of the elements under investigation to the measured lattice parameter of the  and  phase. The residual chemical segregation and especially the coherency stress-induced tetragonal distortion of the  matrix lattice in the high Mo containing alloys results in the observation of two different lattice parameters for the  matrix phase. This leads to three overlapping, but clearly distinguishable {002} X-ray reflections.

Inclusion compounds of a diol host with xylidines: controlled stoichiometries

2002 ◽  
Vol 58 (2) ◽  
pp. 251-259 ◽  
Author(s):  
Luigi R. Nassimbeni ◽  
Hong Su
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Crystallization Temperature ◽  
Inclusion Compounds ◽  
Dsc Analysis ◽  
X Ray Diffraction ◽  
Thermal Stabilities ◽  
X Ray ◽  
Kinetics Of

The diol host, 1,1′-bis-(4-hydroxyphenyl)cyclohexane (DHPC) and a number of xylidine isomers as guests formed a series of inclusion compounds that gave rise to various host:guest ratios controlled by crystallization temperatures. For the host DHPC with a particular xylidine isomer, the number of guests included generally decreases as the crystallization temperature increases. The crystal structures of these host–guest compounds were elucidated using single-crystal X-ray diffraction. Their thermal stabilities were characterized by TG and DSC analysis. The selectivity of enclathration by the host was measured by carrying out a series of competition experiments. The kinetics of guest decomposition were studied using isothermal and non-isothermal methods and reconciled with the crystal structures.

scholarly journals In-situ X-ray diffraction snapshotting: Determination of the kinetics of a photodimerization within a single crystal

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Fei-Long Hu ◽  
Shu-Long Wang ◽  
Jian-Ping Lang ◽  
Brendan F. Abrahams
Keyword(s):  
Single Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Kinetics Of

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

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