scholarly journals Fabrication and Characterization of the Newly Developed Superalloys Based on Inconel 740

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2362 ◽  
Author(s):  
Małgorzata Grudzień-Rakoczy ◽  
Łukasz Rakoczy ◽  
Rafał Cygan ◽  
František Kromka ◽  
Zenon Pirowski ◽  
...  
Keyword(s):  
Solidus Temperature ◽  
Chemical Compositions ◽  
Scanning Calorimetry ◽  
Dendritic Microstructure ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Fabrication And Characterization ◽  
The Difference

The chemical composition of standard Inconel 740 superalloy was modified by changes in the Al/Ti ratio (0.7, 1.5, 3.4) and addition of Ta (2.0, 3.0, 4.0%). Remelted Inconel 740 (A0) and nine variants with various chemical compositions were fabricated by lost-wax casting. The microstructure, microsegregation, phase transformation temperatures, thermal expansion coefficients and hardness of the superalloys were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, differential scanning calorimetry, dilatometry and Vickers measurements. Typical dendritic microstructure was revealed with microsegregation of the alloying elements. Segregation coefficient ki for Ti, Nb and Ta did not exceed unity, and so precipitates enriched mainly in these elements were found in interdendritic spaces. The Nb-rich blocky precipitates, MC carbides, MN nitrides, oxides, and fine γ’ was in all modified castings. Presence of other microstructural features, such as Ti-rich needles, eutectic γ-γ’ islands, small Al-rich and Cr-rich precipitates depended on the casting composition. The lowest solidus and liquidus temperatures were observed in superalloys with a high Al/Ti ratio. Consequently, in A7–A9 variants, the solidification range did not exceed 100 °C. In the A0 variant the difference between liquidus and solidus temperature was 138 °C. Hardness of all modified superalloys was at least 50% higher than for the remelted Inconel 740 (209 HV10).

X-ray powder diffraction characterization of the elusive tetraphosphine Si(CH2PPh2)4 silane

2007 ◽  
Vol 22 (1) ◽  
pp. 55-58 ◽  
Author(s):  
Norberto Masciocchi ◽  
Simona Galli ◽  
Mona Bogza ◽  
Janet Blümel
Keyword(s):  
Powder Diffraction ◽  
Soft Materials ◽  
Molecular Structures ◽  
Tetragonal Symmetry ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Full Profile ◽  
Expansion Coefficients ◽  
Cp Mas Nmr

X-ray powder diffraction data for the tetraphosphinic Si(CH2PPh2)4 silane are reported. Its crystal and molecular structures were determined by simulated annealing and full-profile Rietveld refinement methods. Si(CH2PPh2)4 was found to have tetragonal symmetry with P-421c space group. The lattice parameters were determined to be a=17.211(2) Å, c=7.553(1) Å, V=2237.5(5) Å3. The crystal structure was found to contain isolated Si(CH2PPh2)4 molecules. In each Si(CH2PPh2)4 molecule, the central Si atom was fixed at the −4 symmetric position bearing four CH2PPh2 branches. This environment was confirmed by 31P CP/MAS NMR measurements. Thermo-diffractometric measurements in the 20–120 °C range were also used to estimate the linear and volumetric thermal expansion coefficients (∂ ln V/∂T=1.8×10−4 K−1), typical for very “soft” materials.

Growth and Thermal Characterization of Yb:Y0.923Lu0.071VO4

2013 ◽  
Vol 709 ◽  
pp. 192-196
Author(s):  
Shi Ming Zhang ◽  
Bing Teng ◽  
De Gao Zhong ◽  
Bing Tao Zhang ◽  
Shu Jie Zhuang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Diffusion Coefficients ◽  
Laser Crystal ◽  
Thermal Characterization ◽  
Czochralski Method ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Structure Density

A new mixed laser crystal, Yb0.006Y0.923Lu0.071VO4, has been successfully grown using the Czochralski method. X-ray powder diffraction analysis shows that the crystal has ZrSiO4 structure. Density, thermal expansion coefficients, specific heat and thermal diffusion coefficients were measured, and the thermal conductivity coefficients were determined.

Strained Linbo3/Sapphire Heterostructures Grown by Pulsed Laser Deposition

1995 ◽  
Vol 397 ◽  
Author(s):  
Yoshihiko Shibata ◽  
Naohiro Kuze ◽  
Masahiro Matsui ◽  
Masaki Kanai ◽  
Tomoji Kawai
Keyword(s):  
Diffraction Analysis ◽  
Pulsed Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Thermal Expansion Coefficients ◽  
Transmission Electron ◽  
Expansion Coefficients ◽  
The Difference ◽  
Deposited Films

ABSTRACTThin LiNbO3 films are deposited on (001) sapphire substrates by Ar F pulsed laser ablation. The films are evaluated by X-ray diffraction analysis at various temperatures, as well as high-resolution transmission electron microscopy (TEM). The deposited films are highly epitaxial but that are strained, that is, the a-axis is longer and the c-axis is shorter than those of LiNbO3 single crystals. X-ray diffraction analysis at deposition temperature, as well as TEM show that the strain is caused by the difference in thermal expansion coefficients between LiNbO3 and sapphire substrates.

Thermal Stability of the Structural and Electronic Properties of Strain Symmetrized Sim Gen Superlattices and Ungraded, Nearly Relaxed Si1−x Gex

1992 ◽  
Vol 281 ◽  
Author(s):  
P. A. Dafesh ◽  
P. M. Adams ◽  
V. Arbet-Engels ◽  
K. L. Wang
Keyword(s):  
Thermal Expansion ◽  
Energy Shift ◽  
Buffer Layers ◽  
X Ray ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Structural And Electronic Properties ◽  
Expansion Coefficients ◽  
The Difference ◽  
Anneal Temperature

ABSTRACTIn this study, photoreflectance (PR) spectroscopy and x-ray rocking curves measurements were used to study the variation in strain configuration, defect propagation, structural properties and direct electronic transition energies in Sim Gen superlattices (SL) and nearly relaxed Si1−x Gex buffer layers grown on < 100 > Si as a function of annealing temperature. The in-plane (a│) and perpendicular (a┴) lattice constants of the alloy buffer layers are found to vary only slightly with anneal temperature, TA, up to a temperature To. For TA To, the in-plane strain changed from roughly zero a│ ≈ a┴ (relaxed) or a┴ > a│ (compressive) to a┴ > a│ (tensile). This change in strain configuration is believed to be caused by the difference in thermal expansion coefficients between the epilayer and the Si substrate. The anneal temperature T0 is also correlated with the disappearance of higher order x-ray harmonics from the SL. This point was also correlated with a large energy shift and broadening of the PR spectra from the SL. The shift in energy of the PR spectra is explained in terms of the interdiffusion of Si and Ge at SL heterointerfaces, and to a lesser degree, the strain induced by the above mentioned difference in thermal expansion coefficients. The PR spectra of the alloy E0 transitions are also observed to shift to higher energy with increasing TA.

THE EFFECT OF ANNEALING TEMPERATURES ON THE MICROSTRUCTURE OF La0.5Ca0.5MnO3 FILMS

2002 ◽  
Vol 16 (27) ◽  
pp. 1049-1059 ◽  
Author(s):  
X. M. CHEN ◽  
Y. WANG ◽  
C. X. LIU ◽  
Y. N. ZHAO ◽  
M. LI ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Film Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Thermal Expansion Coefficients ◽  
Atomic Force ◽  
Different Temperatures ◽  
Expansion Coefficients ◽  
The Difference

La 0.5 Ca 0.5 MnO 3 (LCMO) thin films grown by pulsed laser deposition (PLD) and annealed at different temperatures were investigated by high angle X-ray diffraction, atomic force microscope (AFM), scanning electron microscope (SEM), and energy dispersive spectroscopy (SEM-EDS). The lattice parameters, surface morphology as well as the metal compositions of the films were obtained. It was found that the surface morphology of the films strongly depends on the annealing temperatures. The difference of the thermal expansion coefficients between the film and the substrate plays an important role in determining the morphology of the film surface. It induces an in-plane compressive stress in the LCMO films. The strains in the film can be relaxed by nanoscale grains and cracks.

Studies on the Preparation, Characterization and Solubility of -Cyclodextrin-Roxythromycin Inclusion Complexes

2009 ◽  
Vol 2 (2) ◽  
pp. 523-530
Author(s):  
D. Nagasamy Venkatesh ◽  
S. Karthick ◽  
M. Umesh ◽  
G. Vivek ◽  
R.M. Valliappan ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Inclusion Complexes ◽  
Phase Solubility ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ir Studies ◽  
Poorly Soluble ◽  
Poorly Soluble Drug

Roxythromycin/ β-cyclodextrin (Roxy/ β-CD) dispersions were prepared with a view to study the influence of β-CD on the solubility and dissolution rate of this poorly soluble drug. Phase-solubility profile indicated that the solubility of roxythromycin was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Physical characterization of the prepared systems was carried out by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and IR studies. Solid state characterization of the drug β-CD binary system using XRD, FTIR and DSC revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement of dissolution rate.

Thermal Behaviour of Candesartan Active substance and in pharmaceutical compounds

2017 ◽  
Vol 68 (8) ◽  
pp. 1895-1902
Author(s):  
Ioana Cristina Tita ◽  
Eleonora Marian ◽  
Bogdan Tita ◽  
Claudia Crina Toma ◽  
Laura Vicas
Keyword(s):  
Thermal Behaviour ◽  
Active Substance ◽  
Pharmaceutical Research ◽  
Pharmaceutical Product ◽  
Nitrogen Atmosphere ◽  
Pure Substance ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ft Ir

Thermal analysis is one of the most frequently used instrumental techniques in the pharmaceutical research, for the thermal characterization of different materials from solids to semi-solids, which are of pharmaceutical relevance. In this paper, simultaneous thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) were used for characterization of the thermal behaviour of candesartan cilexetil � active substance (C-AS) under dynamic nitrogen atmosphere and nonisothermal conditions, in comparison with pharmaceutical product containing the corresponding active substance. It was observed that the commercial samples showed a different thermal profile than the standard sample, caused by the presence of excipients in the pharmaceutical product and to possible interaction of these with the active substance. The Fourier transformed infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRPD) were used as complementary techniques adequately implement and assist in interpretation of the thermal results. The main conclusion of this comparative study was that the TG/DTG and DSC curves, together with the FT-IR spectra, respectively X-ray difractograms constitute believe data for the discrimination between the pure substance and pharmaceutical forms.

scholarly journals New Insights into the Crystal Chemistry of Elpidite, Na2Zr[Si6O15]·3H2O and (Na1+YCax□1−X−Y)Σ=2Zr[Si6O15]·(3−X)H2O, and Ab Initio Modeling of IR Spectra

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2160
Author(s):  
Alexander Bogdanov ◽  
Ekaterina Kaneva ◽  
Roman Shendrik
Keyword(s):  
Ir Spectra ◽  
Structural Models ◽  
Chemical Characterization ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Special Group ◽  
X Ray ◽  
Influence Of Water ◽  
Radioactive Species

Elpidite belongs to a special group of microporous zirconosilicates, which are of great interest due to their capability to uptake various molecules and ions, e.g., some radioactive species, in their structural voids. The results of a combined electron probe microanalysis and single-crystal X-ray diffraction study of the crystals of elpidite from Burpala (Russia) and Khan-Bogdo (Mongolia) deposits are reported. Some differences in the chemical compositions are observed and substitution at several structural positions within the structure of the compounds are noted. Based on the obtained results, a detailed crystal–chemical characterization of the elpidites under study was carried out. Three different structure models of elpidite were simulated: Na2ZrSi6O15·3H2O (related to the structure of Russian elpidite), partly Ca-replaced Na1.5Ca0.25ZrSi6O15·2.75H2O (close to elpidite from Mongolia), and a hypothetical CaZrSi6O15·2H2O. The vibration spectra of the models were obtained and compared with the experimental one, taken from the literature. The strong influence of water molecule vibrations on the shape of IR spectra of studied structural models of elpidite is discussed in the paper.

Influence of Magnetoelastic Anisotropy on Properties of Nanostructured Microwires

2013 ◽  
Vol 646 ◽  
pp. 59-66 ◽  
Author(s):  
Arcady Zhukov ◽  
Margarita Churyukanova ◽  
Lorena Gonzalez-Legarreta ◽  
Ahmed Talaat ◽  
Valentina Zhukova ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Hysteresis Loops ◽  
Magnetic Behaviour ◽  
Soft Magnetic ◽  
Magnetoelastic Anisotropy ◽  
Thermal Expansion Coefficients ◽  
Magnetoelastic Energy ◽  
Expansion Coefficients ◽  
The Difference ◽  
Magneto Resistance

We studied the effect ofthe magnetoelastic ansitropy on properties of nanostructured glass-coated microwires with soft magnetic behaviour (Finemet-type microwires of Fe70.8Cu1Nb3.1Si14.5B10.6, Fe71.8Cu1Nb3.1Si15B9.1 and Fe73.8Cu1Nb3.1Si13B9.1 compositions) and with granular structure (Cu based Co-Cu microwires). The magnetoelastic energy originated from the difference in thermal expansion coefficients of the glass and metallic alloy during the microwires fabrication, affected the hysteresis loops, coercivity and heat capacity of Finemet-type microwires. Hysteresis loops of all as-prepared microwires showed rectangular shape, typical for Fe-rich microwires. As expected, coercivity, HC, of as-prepared microwires increases with decreasing of the ratio ρ defined as the ratio between the metallic nucleus diameter, d to total microwire diameter, D. On the other hand we observed change of heat capacity in microwires with different ratio ρ. In the case of Co-Cu microwires ρ- ratio affected the structure and the giant magneto-resistance of obtained microwires.

scholarly journals Fabrication and characterization of Si-based soft x-ray mirrors

1991 ◽  
Author(s):  
Bernt Schmiedeskamp ◽  
Bernhard Heidemann ◽  
Ulf Kleineberg ◽  
Andreas Kloidt ◽  
Mikhael Kuehne ◽  
...  
Keyword(s):  
X Ray ◽  
Fabrication And Characterization
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