The Debye Temperature and the Coefficient of Thermal Expansion for V and Nb by X-Ray Diffraction

1970 ◽  
Vol 37 (2) ◽  
pp. K89-K91 ◽  
Author(s):  
M. Linkoaho ◽  
E. Rantavuori
1991 ◽  
Vol 227 ◽  
Author(s):  
C. K Ober ◽  
G. G. Barclay

ABSTRACTNew liquid crystalline thermosets have been prepared from end-functional monomers and oligomers of varying molecular weight. Both triazine and epoxy networks were explored. Of primary interest was the exploitation of the mesophase properties of these networks for developing polymers with high thermal stability and low coefficients of thermal expansion (CTE). Curing was carried out either within the nematic mesophase or the isotropic phase of the prepolymers. Transition temperatures associated with the mesophase were observed to change after curing under these two sets of conditions. The networks with the highest crosslink density were found to exhibit the lowest CTE values. Crosslinking of these thermosets was also carried out in the presence of a 13.5 Tesla magnetic field to determine the effect of orienting fields on the curing of the LC network. Orientation parameters as measured by wide angle x-ray diffraction were as high as 0.6. Values of the coefficient of thermal expansion as low as 15 ppm were achieved in the aligned direction. Of the two resin types, those with the triazine crosslinks had the lowest thermal expansion coefficient. Other thermal properties of these networks will be discussed.


2014 ◽  
Vol 47 (3) ◽  
pp. 819-826 ◽  
Author(s):  
Bastian Brink ◽  
Kenny Ståhl ◽  
Thomas L. Christiansen ◽  
Marcel A. J. Somers

Nitrogen-expanded austenite, γN, with high and low nitrogen contents was produced from AISI 316 grade stainless steel powder by gaseous nitriding in ammonia/hydrogen gas mixtures.In situsynchrotron X-ray diffraction was applied to investigate the thermal expansion and thermal stability of expanded austenite in the temperature range 385–920 K. Evaluation of the diffractograms of the sample with a high nitrogen content, corresponding to an occupancy of the interstitial lattice of 56%, with Rietveld refinement yielded a best convergence after including the stacking fault probability as a fitting parameter. The stacking fault density is constant for temperatures up to 680 K, whereafter it decreases to nil. Surprisingly, a transition phase with compositionM4N (M= Fe, Cr, Ni, Mo) appears for temperatures above 770 K. The linear coefficient of thermal expansion depends on the nitrogen content and is lowest for the sample with a high level of nitrogen.


2016 ◽  
Vol 848 ◽  
pp. 703-708
Author(s):  
Liu Qing Liang ◽  
Ling Min Zeng ◽  
Shu Hui Liu ◽  
De Gui Li ◽  
Ming Qin

The ternary compound DyCo0.67Ga1.33 was synthesized and the thermal expansion of DyCo0.67Ga1.33 was studied in the temperature range of 309–608 K by high temperature powder X-ray diffraction technique. The volumetric coefficient of thermal expansion, , can be represented by . Its magnetic properties were measured between 30 and 300 K, and the magnetic susceptibility of DyCo0.67Ga1.33 was found to follow the Curie–Weiss law in the temperature range of 40–300 K. The effective magnetic moment and paramagnetic Curie temperature were estimated to be 9.86 μB and 40.4 K, respectively. Electrical resistivity of the compound DyCo0.67Ga1.33 was also measured between 5 and 300 K. Temperature variation of the electrical resistivity suggests the metallic character of the compound DyCo0.67Ga1.33 with an anomaly detected at 45 K. The residual resistivity ratio RRR of the compound is about 1.2.


2006 ◽  
Vol 955 ◽  
Author(s):  
Lisa Mercurio ◽  
James H. Edgar ◽  
Li Du ◽  
E. A. Kenik

ABSTRACTTitanium nitride crystals were grown from titanium nitride powder on tungsten by the sublimation-recondensation technique. The bright golden TiN crystals displayed a variety of shapes including cubes, truncated tetrahedrons, truncated octahedrons, and tetrahedrons bounded by (111) and (100) crystal planes. The TiN crystals formed regular, repeated patterns within individual W grains that suggested epitaxy. X-ray diffraction and electron backscattering diffraction revealed that the tungsten foil was highly textured with a preferred foil normal of (100) and confirmed that the TiN particles deposited epitaxially with the orientation TiN(100)‖W(100) and TiN[100]‖W[110], that is, the unit cells of the TiN crystals were rotated 45° with respect to the tungsten. Because of its larger coefficient of thermal expansion compared to W, upon cooling from the growth temperature, the TiN crystals were under in-plane tensile strain, causing many of the TiN crystals to crack.


2013 ◽  
Vol 46 (2) ◽  
pp. 550-553 ◽  
Author(s):  
Z.A. Jones ◽  
P. Sarin ◽  
R. P. Haggerty ◽  
W. M. Kriven

The coefficient of thermal expansion analysis suite (CTEAS) has been developed to calculate and visualize thermal expansion properties of crystalline materials in three dimensions. The software can be used to determine the independent terms of the second-rank thermal expansion tensor usinghklvalues, correspondingdhkllistings and lattice constants obtained from powder X-ray diffraction patterns collected at different temperatures. UsingCTEAS, a researcher can also visualize the anisotropy of this essential material property in three dimensions. In-depth understanding of the thermal expansion of crystalline materials can be a useful tool in understanding the dependence of the thermal properties of materials on temperature when correlated with the crystal structure.


2018 ◽  
Vol 281 ◽  
pp. 389-394
Author(s):  
Yuan Yuan Song ◽  
Yuan Yuan Zhou ◽  
Yang Wang ◽  
Lan Li ◽  
Fu Tian Liu

Ceramics with the formula Ca1-xSrxZr4(PO4)6 (x=0.4, 0.45, 0.5, 0.55) have been synthesized by coprecipitation method, an. their structures, phase transitions, thermal expansion properties have been studied by differential sanning calorimetry, scanning electron microscope, X-ray diffraction and dilatometer. The results show that Ca1-xSrxZr4(PO4)6 ceramics sintered at 1400°C had good sintering condition. Unit cell volume basically had no change with substitution of Ca by Sr. The coprecipitation method saved energy and time. It was introduced to increase the relative density of Ca0.5Sr0.5Zr4(PO4)6 ceramic. The coefficient of thermal expansion was about 1.447×10-6/°C.


2019 ◽  
Vol 946 ◽  
pp. 336-340
Author(s):  
Svetlana A. Gudkova ◽  
Danil A. Uchaev ◽  
D.A. Vinnik

Strontium hexaferrite is a well-known material, due to its application in microelectronics. This paper is devoted to strontium hexaferrite single crystals, obtained by the spontaneous crystallization technique with sodium based flux. SrFe12O19 crystals were grounded, pressed to the tablets, and crystals cell parameters were measured by thermal X-ray diffraction technique. Coefficient of thermal expansion calculated from the X-ray thermal diffraction data is in a good agreement with dilatometric measurements.


2018 ◽  
Vol 25 (02) ◽  
pp. 1850059
Author(s):  
QIANG FENG ◽  
JIA SHE ◽  
YONG XIANG ◽  
XIANYUN WU ◽  
CHENGXI WANG ◽  
...  

The depth profiles of residual stresses and lattice parameters in the surface layers of shot peened duplex stainless steel at elevated temperature were investigated utilizing X-ray diffraction analysis. At each deformation depth, residual stress distributions in both ferrite and austenite were studied by X-ray diffraction stress analysis which is performed on the basis of the sin[Formula: see text] method and the lattice parameters were explored by Rietveld method. The results reveal that difference changes of depth residual compressive stress profiles between ferrite and austenite under the same annealing condition are resulted from the diverse coefficient of thermal expansion, dislocation density, etc. for different phases in duplex stainless steel. The relaxations of depth residual stresses in austenite are more obvious than those in ferrite. The lattice parameters decrease in the surface layer with the extending of annealing time, however, they increase along the depth after annealing for 16[Formula: see text]min. The change of the depth lattice parameters can be ascribed to both thermal expansion and the relaxation of residual stress. The different changes of microstructure at elevated temperature between ferrite and austenite are discussed.


2013 ◽  
Vol 380-384 ◽  
pp. 4303-4306
Author(s):  
Ya Jing Zhang ◽  
Li Xin Li

The structure and thermal parameters of biomedical used Ni20Pd80 alloy were studied using X-ray diffraction (XRD) technique. The diffraction experiments performed in the temperature range of 308-1100 K revealed that the alloy forms a face centered cubic (fcc) A1-type structure. The temperature dependence of the lattice parameters was investigated using the Bragg line displacement method shows that the lattice parameter increases with the increase of temperature. The mean linear thermal expansion (MLTE (%)), coefficient of thermal expansion (CTE) α, the characteristic Debye temperature (ΘD) and mean square amplitudes of vibration were determined from the XRD data. The value of Debye temperature was found to be 253 K. It was found that temperature factor was independent of the static displacements.


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