In-situ X-ray tomography investigation of pore damage effects during a tensile test of a Ni-based single crystal superalloy

2021 ◽  
pp. 111180
Author(s):  
Keli Liu ◽  
Junsheng Wang ◽  
Bing Wang ◽  
Pengcheng Mao ◽  
Yanhong Yang ◽  
...  
Keyword(s):  
Tensile Test ◽  
Single Crystal ◽  
Single Crystal Superalloy ◽  
X Ray

scholarly journals Crack Propagation Behavior of a Ni-Based Single-Crystal Superalloy during In Situ SEM Tensile Test at 1000 °C

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1047
Author(s):  
Wenxiang Jiang ◽  
Xiaoyi Ren ◽  
Jinghao Zhao ◽  
Jianli Zhou ◽  
Jinyao Ma ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Tensile Test ◽  
Single Crystal ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Single Crystal Superalloy ◽  
Propagation Path ◽  
Propagation Behavior ◽  
Crack Propagation Behavior

An in situ scanning electron microscope (SEM) tensile test for Ni-based single-crystal superalloy was carried out at 1000 °C. The stress displacement was obtained, and the yield strength and tensile strength of the superalloy were 699 MPa and 826 MPa, respectively. The crack propagation process, consisting of Model I crack and crystallographic shearing crack, was determined. More interestingly, the crack propagation path and rate affected by eutectics was directly observed and counted. Results show that the coalescence of the primary crack and second microcrack at the interface of a γ/γ′ matrix and eutectics would make the crack propagation rate increase from 0.3 μm/s to 0.4 μm/s. On the other hand, crack deflection decreased the rate to 0.05 μm/s. Moreover, movement of dislocations in front of the crack was also analyzed to explain the different crack propagation behavior in the superalloy.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

Time Dependence of γ/γ' Lattice Mismatch in Creep-Deformed Single Crystal Superalloy SC16 at 1173 K

2007 ◽  
Vol 539-543 ◽  
pp. 3059-3063 ◽  
Author(s):  
G. Schumacher ◽  
N. Darowski ◽  
I. Zizak ◽  
Hellmuth Klingelhöffer ◽  
W. Chen ◽  
...  
Keyword(s):  
Single Crystal ◽  
Lattice Mismatch ◽  
Lattice Misfit ◽  
Peak Position ◽  
Single Crystal Superalloy ◽  
Tensile Creep ◽  
Full Width ◽  
X Ray Diffraction ◽  
X Ray ◽  
Time Period

The profiles of 001 and 002 reflections have been measured at 1173 K as a function of time by means of X-ray diffraction (XRD) on tensile-creep deformed specimens of single crystal superalloy SC16. Decrease in line width (full width at half maximum: FWHM) by about 7 % and increase in peak position by about 3x10-4 degrees was detected after 8.5x104 s. Broadening of the 002 peak profile indicated a more negative value of the lattice misfit after the same time period. The results are discussed in the context of the anisotropic arrangement of dislocations at the γ/γ’ interfaces during creep and their rearrangement during the thermal treatment at 1173 K.

Ultrasound-Promoted Synthesis of Spirocyclopropanes from Switchable Starting Materials via Azomethine Ylide [3+2]-Cycloaddition

Synthesis ◽  
2021 ◽  
Author(s):  
Issa Yavari ◽  
Sara Sheikhi ◽  
Jamil Sheykhahmadi ◽  
Zohreh Taheri ◽  
Mohammad Reza Halvagar
Keyword(s):  
Single Crystal ◽  
Azomethine Ylides ◽  
Azomethine Ylide ◽  
X Ray ◽  
Green Protocol ◽  
Stereogenic Centers ◽  
Quinoxaline Derivatives ◽  
Excellent Selectivity

AbstractAn ultrasound-promoted green protocol to access a new series of spirocyclopropanes from indeno[1,2-b]quinoxaline derivatives and azomethine ylides, generated in situ from the iodine-catalyzed reaction of acetophenones as well as of 2-methylquinoline with pyridine in the presence of a base, is described. These transformations proceed via a spirocyclopropanation reaction followed by elimination of pyridine. Clear evidence for the structure of a spirocyclopropane-linked indenoquinoxaline derivative was obtained from single-crystal X-ray analysis. The most important feature of this reaction is the fact it forms three stereogenic centers, one of which is quaternary, with excellent selectivity.

scholarly journals X-Ray Single Crystal Structural Analysis of Magnetically Oriented Microcrystals

2014 ◽  
Vol 70 (a1) ◽  
pp. C1138-C1138
Author(s):  
Chiaki Tsuboi ◽  
Kazuki Aburaya ◽  
Shingo Higuchi ◽  
Fumiko Kimura ◽  
Masataka Maeyama ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Single Crystal ◽  
Three Dimensional ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Data Set ◽  
Uv Curable ◽  
X Ray

We have developed magnetically oriented microcrystal array (MOMA) technique that enables single crystal X-ray diffraction analyses from microcrystalline powder. In this method, microcrystals suspended in a UV-curable monomer matrix are there-dimensionally aligned by special rotating magnetic field, followed by consolidation of the matrix by photopolymerization. From thus achieved MOMAs, we have been succeeded in crystal structure analysis for some substances [1, 2]. Though MOMA method is an effective technique, it has some problems as follows: in a MOMA, the alignment is deteriorated during the consolidation process. In addition, the sample microcrystals cannot be recovered from a MOMA. To overcome these problems, we performed an in-situ X-ray diffraction measurement using a three-dimensional magnetically oriented microcrystal suspension (3D MOMS) of L-alanine. An experimental setting of the in-situ X-ray measurement of MOMS is schematically shown in the figure. L-alanine microcrystal suspension was poured into a glass capillary and placed on the rotating unit equipped with a pair of neodymium magnets. Rotating X-ray chopper with 10°-slits was placed between the collimator and the suspension. By using this chopper, it was possible to expose the X-ray only when the rotating MOMS makes a specific direction with respect to the impinging X-ray. This has the same effect as the omega oscillation in conventional single crystal measurement. A total of 22 XRD images of 10° increments from 0° to 220° were obtained. The data set was processed by using conventional software to obtain three-dimensional molecular structure of L-alanine. The structure is in good agreement with that reported for the single crystal. R1 and wR2 were 6.53 and 17.4 %, respectively. RMSD value between the determined molecular structure and the reported one was 0.0045 Å. From this result, we conclude that this method can be effective and practical to be used widely for crystal structure analyses.

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