Martensitic transformation of Ni2.18Mn0.82Ga single crystal observed by neutron diffraction and synchrotron radiation white X-ray diffraction

2006 ◽  
Vol 438-440 ◽  
pp. 131-135 ◽  
Author(s):  
K. Inoue ◽  
Y. Yamaguchi ◽  
K. Ohsumi ◽  
Y. Noda ◽  
H. Kimura ◽  
...  
2005 ◽  
pp. 2017-2020
Author(s):  
Kazuko Inoue ◽  
Yasuo Yamaguchi ◽  
Kazumasa Ohsumi ◽  
Katsuhiro Kusaka ◽  
Takeshi Nakagawa

2005 ◽  
Vol 46 (6) ◽  
pp. 1425-1432 ◽  
Author(s):  
Kazuko Inoue ◽  
Yasuo Yamaguchi ◽  
Kazumasa Ohsumi ◽  
Katsuhiro Kusaka ◽  
Takeshi Nakagawa

2005 ◽  
Vol 475-479 ◽  
pp. 2017-2020
Author(s):  
Kazuko Inoue ◽  
Yasuo Yamaguchi ◽  
Kazumasa Ohsumi ◽  
Katsuhiro Kusaka ◽  
Takeshi Nakagawa

A Heusler-type Ni2.18Mn0.82Ga single crystal shows a shape memory effect. It makes a thermo-elastic martensitic transformation at around 340 K, which is coincident with a Curie temperature. We made a synchrotron radiation white X-ray diffraction of the single crystal by changing the temperature from 400 K to 103 K. We observed the change of Laue spots following the transformation. As a result of experiment, the single crystal shows one cubic Heusler structure at 400 K. The direction of the crystal growth is along cubic [010] direction. In the process of decreasing temperature, many tetragonal structures with small volume of different axial direction become to appear. At room temperature the transformation almost finishes and two tetragonal Heusler structures which are twin each other remain. One of them is nearly the same as the structure at the beginning room temperature. The direction of the crystal growth is [010] of this tetragonal structure. We found that the twinning plane of the tetragonal structure is (011) plane.


2017 ◽  
Vol 81 (4) ◽  
pp. 917-922
Author(s):  
Peter Elliott

AbstractThe crystal structure of the copper aluminium phosphate mineral sieleckiite, Cu3Al4(PO4)2 (OH)12·2H2O, from the Mt Oxide copper mine, Queensland, Australia was solved from single-crystal X-ray diffraction data utilizing synchrotron radiation. Sieleckiite has monoclinic rather than triclinic symmetry as previously reported and is space group C2/m with unit-cell parameters a = 11.711(2), b = 6.9233(14), c = 9.828(2) Å, β = 92.88(3)°, V = 795.8(3) Å3and Z = 2. The crystal structure, which has been refined to R1 = 0.0456 on the basis of 1186 unique reflections with Fo > 4σF, is a framework of corner-, edge- and face- sharing Cu and Al octahedra and PO4 tetrahedra.


2013 ◽  
Vol 772 ◽  
pp. 193-199 ◽  
Author(s):  
Carsten Ohms ◽  
Rene V. Martins

Bi-metallic piping welds are frequently used in light water nuclear reactors to connect ferritic steel pressure vessel nozzles to austenitic stainless steel primary cooling piping systems. An important aspect for the integrity of such welds is the presence of residual stresses. Measurement of these residual stresses presents a considerable challenge because of the component size and because of the material heterogeneity in the weld regions. The specimen investigated here was a thin slice cut from a full-scale bi-metallic piping weld mock-up. A similar mock-up had previously been investigated by neutron diffraction within a European research project called ADIMEW. However, at that time, due to the wall thickness of the pipe, stress and spatial resolution of the measurements were severely restricted. One aim of the present investigations by high energy synchrotron radiation and neutrons used on this thin slice was to determine whether such measurements would render a valid representation of the axial strains and stresses in the uncut large-scale structure. The advantage of the small specimen was, apart from the easier manipulation, the fact that measurement times facilitated a high density of measurements across large parts of the test piece in a reasonable time. Furthermore, the recording of complete diffraction patterns within the accessible diffraction angle range by synchrotron X-ray diffraction permitted mapping the texture variations. The strain and stress results obtained are presented and compared for the neutron and synchrotron X-ray diffraction measurements. A strong variation of the texture pole orientations is observed in the weld regions which could be attributed to individual weld torch passes. The effect of specimen rocking on the scatter of the diffraction data in the butt weld region is assessed during the neutron diffraction measurements.


Author(s):  
Giulia Novelli ◽  
Charles J. McMonagle ◽  
Florian Kleemiss ◽  
Michael Probert ◽  
Horst Puschmann ◽  
...  

The crystal structure of the monoclinic polymorph of the primary amino acid L-histidine has been determined for the first time by single-crystal neutron diffraction, while that of the orthorhombic polymorph has been reinvestigated with an untwinned crystal, improving the experimental precision and accuracy. For each polymorph, neutron diffraction data were collected at 5, 105 and 295 K. Single-crystal X-ray diffraction experiments were also performed at the same temperatures. The two polymorphs, whose crystal packing is interpreted by intermolecular interaction energies calculated using the Pixel method, show differences in the energy and geometry of the hydrogen bond formed along the c direction. Taking advantage of the X-ray diffraction data collected at 5 K, the precision and accuracy of the new Hirshfeld atom refinement method implemented in NoSpherA2 were probed choosing various settings of the functionals and basis sets, together with the use of explicit clusters of molecules and enhanced rigid-body restraints for H atoms. Equivalent atomic coordinates and anisotropic displacement parameters were compared and found to agree well with those obtained from the corresponding neutron structural models.


1999 ◽  
Vol 55 (5) ◽  
pp. 726-735 ◽  
Author(s):  
N. Ishizawa ◽  
Y. Matsushima ◽  
M. Hayashi ◽  
M. Ueki

The fluorite-related cubic structure of yttria-stabilized zirconia, Zr0.75 8Y0.24 2O1.87 9, has been studied by single-crystal X-ray diffraction using synchrotron radiation and by EXAFS. Two diffraction data sets obtained at X-ray energies of 512 and 10 eV below the Y K edge revealed that in the average structure Zr atoms are displaced from the origin of the space group Fm3¯m along 〈111〉 by 0.19 Å, while Y atoms reside at the origin. Approximately 48% of the O atoms occupy the ideal position in the fluorite-type structure, while 43% of O atoms are displaced from the ideal position along 〈001〉 by 0.31 Å. The remaining 9% of O atoms are presumably sited at interstitial positions. Local structures around Zr and Y are investigated by combining the results of single-crystal X-ray diffraction and EXAFS studies.


2010 ◽  
Vol 163 ◽  
pp. 295-298 ◽  
Author(s):  
Jan Drahokoupil ◽  
Petr Haušild ◽  
Vadim Davydov ◽  
P. Pilvin

Kinetics of deformation induced martensitic transformation in metastable austenitic AISI 301 steel was characterized by several techniques including classical light metallography, X-ray diffraction, neutron diffraction and electron back scattered diffraction. In order to characterize the martensitic transformation, several specimens were tensile pre-deformed to 5%, 10% and 20% of plastic deformation and compared with non-deformed state. During straining, the volume fraction of α’-martensite rapidly prevails over the volume fraction of original austenite and reach the value circa 70%.


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