Neutron-diffraction studies on liquid, glassy, and crystalline Ca0.4K0.6(NO3)1.4

1995 ◽  
Vol 73 (11-12) ◽  
pp. 748-754 ◽  
Author(s):  
E. Kartini ◽  
M. F. Collins ◽  
B. Collier ◽  
F. Mezei ◽  
E. C. Svensson
Keyword(s):  
Neutron Diffraction ◽  
Time Dependence ◽  
Crystallization Process ◽  
Growth Patterns ◽  
Main Peak ◽  
X Ray Diffraction ◽  
Crystalline Powder ◽  
X Ray ◽  
Heat Treated ◽  
Characteristic Growth

The temperature dependence of neutron diffraction by Ca0.4K0.6(NO3)1.4, in the liquid and glassy states, was measured together with the time dependence of the transformation to the crystalline states. The measurements were performed over the range of Q from 0.2 to 5.5 Å−1 (1 Å = 10−10 m) for temperatures between 300 and 573 K. On cooling, a glass was formed with a glass transition temperature of Tg = 335 K; on heating, two crystalline phases formed at 375 ± 5 K with melting points of 425 and 444 K. As the temperature increased the height of the main peak in the diffraction pattern decreased, its position shifted to lower Q, and its width increases. Each of these parameters varies linearly with temperature. The metastability of the system was exemplified by the crystallization process, which did not occur on cooling, but which did occur on first cooling to 300 K and then on heating to 375 K. The time dependence of the growth of the crystalline powder peaks shows that there are two characteristic growth patterns, with each observed peak coming from one of two compounds. We also report on studies of quenched and heat-treated Ca0.4K0.6(NO3)1.4 by thermal analysis and X-ray diffraction.

Magnetite and Anti-Microbial Properties of Ag2O-CaO-Fe2O3-SiO2 Glass-Ceramic by Sol-Gel Method

2011 ◽  
Vol 399-401 ◽  
pp. 869-872
Author(s):  
Bin Li ◽  
Hai Feng Chen ◽  
Li Hua Wen ◽  
Chen Ma
Keyword(s):  
Glass Ceramic ◽  
Crystallization Process ◽  
Sol Gel ◽  
Frequency Factor ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Heat Treated

Ag2O-CaO-Fe2O3-SiO2glass-ceramic was prepared by the sol-gel method. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were used to investigate crystallization process of Ag2O-CaO-Fe2O3-SiO2glass. The kinetic results show that the values of the activation energy and frequency factor of the glass are 441.991 KJ/ mol and 1.58×1020, respectively. And the dimensionality of crystal growth, n, decreases as the heating rate increases. The crystalline phases of the glass-ceramic are magnetite, wollastonite and minor hematite. The saturation magnetization and coercive force of the heat-treated glass are 0.08 Wb/m2and 14 KA/m at room temperature. The glass-ceramic has some capacity of anti-microbial.

scholarly journals Structural, Thermal and Magnetic Analysis of Fe75Co10Nb6B9 and Fe65Co20Nb6B9 Nanostructured Alloys

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4542
Author(s):  
Albert Carrillo ◽  
Jason Daza ◽  
Joan Saurina ◽  
Lluisa Escoda ◽  
Joan-Josep Suñol
Keyword(s):  
Crystallization Process ◽  
Vibrating Sample Magnetometry ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Rich Phase ◽  
X Ray ◽  
Ferromagnetic Alloys ◽  
Heat Treated ◽  
Magnetic Analysis ◽  
Crystalline Growth

Two nanocrystalline ferromagnetic alloys of the Fe-Co-Nb-B system have been produced by mechanical alloying (MA). Their microstructure, thermal behavior and magnetic response were checked by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and vibrating sample magnetometry (VSM). After 80 h of MA, the alloys were nanostructured (bcc-Fe(Co)-rich phase). As the Co content increases, the density of the dislocations decreases. Besides, a higher concentration of Co causes an increase in the activation energy of the crystallization process. The calculated energies, 267 and 332 kJ/mol, are associated to the crystalline growth of the bcc-Fe-rich phase. The Co content of the samples has no effect on the value of the saturation magnetization, whereas the coercivity is lower in the alloy containing less Co. Samples were compacted and heat-treated. Optimal annealing reduces the coercivity by a factor of two. Results were compared with the data of Fe-Nb-B and Fe-Ni-Nb-B alloys.

Texture measurements in Al2O3 using BEKP

1994 ◽  
Vol 52 ◽  
pp. 608-609
Author(s):  
M. D. Vaudin ◽  
J. P. Cline
Keyword(s):  
Neutron Diffraction ◽  
Rapid Method ◽  
Crystallographic Orientation ◽  
Specimen Surface ◽  
X Ray Diffraction ◽  
Anisotropic Crystal ◽  
X Ray ◽  
Verification Method ◽  
Crystal Properties ◽  
Backscattered Electron

The study of preferred crystallographic orientation (texture) in ceramics is assuming greater importance as their anisotropic crystal properties are being used to advantage in an increasing number of applications. The quantification of texture by a reliable and rapid method is required. Analysis of backscattered electron Kikuchi patterns (BEKPs) can be used to provide the crystallographic orientation of as many grains as time and resources allow. The technique is relatively slow, particularly for noncubic materials, but the data are more accurate than any comparable technique when a sufficient number of grains are analyzed. Thus, BEKP is well-suited as a verification method for data obtained in faster ways, such as x-ray or neutron diffraction. We have compared texture data obtained using BEKP, x-ray diffraction and neutron diffraction. Alumina specimens displaying differing levels of axisymmetric (0001) texture normal to the specimen surface were investigated.BEKP patterns were obtained from about a hundred grains selected at random in each specimen.

scholarly journals Stable and Metastable Phase Equilibria Involving the Cu6Sn5 Intermetallic

2021 ◽  
Author(s):  
A. Leineweber ◽  
M. Löffler ◽  
S. Martin
Keyword(s):  
Phase Equilibria ◽  
Electron Backscatter Diffraction ◽  
Metastable Phase ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Ordered Phases ◽  
Backscatter Diffraction ◽  
Kinetics Of

Abstract Cu6Sn5 intermetallic occurs in the form of differently ordered phases η, η′ and η′′. In solder joints, this intermetallic can undergo changes in composition and the state of order without or while interacting with excess Cu and excess Sn in the system, potentially giving rise to detrimental changes in the mechanical properties of the solder. In order to study such processes in fundamental detail and to get more detailed information about the metastable and stable phase equilibria, model alloys consisting of Cu3Sn + Cu6Sn5 as well as Cu6Sn5 + Sn-rich melt were heat treated. Powder x-ray diffraction and scanning electron microscopy supplemented by electron backscatter diffraction were used to investigate the structural and microstructural changes. It was shown that Sn-poor η can increase its Sn content by Cu3Sn precipitation at grain boundaries or by uptake of Sn from the Sn-rich melt. From the kinetics of the former process at 513 K and the grain size of the η phase, we obtained an interdiffusion coefficient in η of (3 ± 1) × 10−16 m2 s−1. Comparison of this value with literature data implies that this value reflects pure volume (inter)diffusion, while Cu6Sn5 growth at low temperature is typically strongly influenced by grain-boundary diffusion. These investigations also confirm that η′′ forming below a composition-dependent transus temperature gradually enriches in Sn content, confirming that Sn-poor η′′ is metastable against decomposition into Cu3Sn and more Sn-rich η or (at lower temperatures) η′. Graphic Abstract

Investigation of Residual Strains of the Second Kind in Plastically Deformed Metallic Materials

1994 ◽  
Vol 376 ◽  
Author(s):  
M. Vrána ◽  
P. Klimanek ◽  
T. Kschidock ◽  
P. Lukáš ◽  
P. Mikula
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Stacking Faults ◽  
Metallic Materials ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Diffractometer ◽  
Residual Strains ◽  
Good Agreement

ABSTRACTInvestigation of strongly distorted crystal structures caused by dislocations, stacking-faults etc. in both plastically deformed f.c.c. and b.c.c. metallic materials was performed by the analysis of the neutron diffraction line broadening. Measurements were realized by means of the high resolution triple-axis neutron diffractometer equipped by bent Si perfect crystals as monochromator and analyzer at the NPI Řež. The substructure parameters obtained in this manner are in good agreement with the results of X-ray diffraction analysis.

PREPARATION OF ANTIMONY-PLATINUM SURFACE ALLOY ELECTRODE BY ATOM DIFFUSION IN THE SOLID PHASE

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3999-4004
Author(s):  
HIROSHI MATSUI ◽  
KAZUFUMI WATANABE
Keyword(s):  
Diffraction Pattern ◽  
Low Temperatures ◽  
Solid Phase ◽  
Electrochemical Measurement ◽  
X Ray Diffraction ◽  
Platinum Surface ◽  
X Ray ◽  
Atom Diffusion ◽  
Heat Treated ◽  
Titanium Substrates

Antimony-platinum bilayers were prepared on titanium substrates by the two-step electrodeposition in the usual baths, and then surface alloys were formed by the atom diffusion in the solid phase. The simple antimony layer was little influenced by the substrate in both the measurements of X-ray diffraction and the i - E characteristic in a sulfuric acid solution. Regarding the bilayers, the catalytic activity in hydrogen evolution reaction was very sensitive to the presence of platinum, while the hydrogen adsorbability was quite insensitive. An interaction between antimony and platinum was confirmed by the appearance of a new dissolution wave in the electrochemical measurement and the occurrence of a new diffraction in the X-ray diffraction pattern after the heat-treatment of about 400°C. Although the new diffraction disagreed with any of the reported alloys, clear diffraction pattern of PtSb 2 alloy was observed, when the bilayers were heat-treated at about 600°C for one hour. Considering the penetration depth of X-ray, the alloying of antimony and platinum seems to occur also at low temperatures at least at the top surface.

Crystallization of Zn-rich and P-rich amorphous Zn3P2 thin films

1988 ◽  
Vol 66 (5) ◽  
pp. 373-375 ◽  
Author(s):  
C. J. Arsenault ◽  
D. E. Brodie
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Activation Energy ◽  
Electrical Properties ◽  
Structural Properties ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Conductivity Activation Energy ◽  
X Ray

Zn-rich and P-rich amorphous Zn3P2 thin films were prepared by co-evaporation of the excess element during the normal Zn3P2 deposition. X-ray diffraction techniques were used to investigate the structural properties and the crystallization process. Agglomeration of the excess element within the as-made amorphous Zn3P2 thin film accounted for the structural properties observed after annealing the sample. Electrical measurements showed that excess Zn reduces the conductivity activation energy and increases the conductivity, while excess P up to 15 at.% does not alter the electrical properties significantly.

Investigation of Residual Stress/Strain and Texture in a Large Dissimilar Metal Weld Using Synchrotron Radiation and Neutrons

2013 ◽  
Vol 772 ◽  
pp. 193-199 ◽  
Author(s):  
Carsten Ohms ◽  
Rene V. Martins
Keyword(s):  
Synchrotron Radiation ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Large Scale ◽  
High Energy ◽  
X Ray Diffraction ◽  
Butt Weld ◽  
X Ray ◽  
Component Size ◽  
Thin Slice

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.

Influence of High Temperature Annealing on Microstructure Evolution of Ni-24Fe-14Cr-8Mo Superalloy

2021 ◽  
Vol 904 ◽  
pp. 117-123
Author(s):  
Yi Cui ◽  
Yun Fei Zhang ◽  
Yan Guang Han ◽  
Da Lv
Keyword(s):  
High Temperature ◽  
Microstructure Evolution ◽  
Testing Machine ◽  
Aging Treatment ◽  
Growth Patterns ◽  
High Temperature Annealing ◽  
Rockwell Hardness ◽  
Hardness Testing ◽  
X Ray Diffraction ◽  
X Ray

The effect of high temperature annealing on microstructure evolution of Ni-24Fe-14Cr-8Mo alloy was investigated through Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Rockwell Hardness Testing Machine. Three kinds of grain growth patterns were found at different annealing temperatures due to carbides precipitation and dissolution. After a combination of high temperature annealing and aging treatment, the hardness versus time curves performed a parabolic pattern. The highest hardness was achieved under 1070°C/60 minutes treatment, and the desirable annealing time should be 60 minutes to 90 minutes.

Hardening of Selective Laser Melted M2 Steel

2021 ◽  
Author(s):  
Mei Yang ◽  
Yishu Zhang ◽  
Haoxing You ◽  
Richard Smith ◽  
Richard D. Sisson
Keyword(s):  
Heat Treatment ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
High Hardness ◽  
Steel Part ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Near Net Shape

Abstract Selective laser melting (SLM) is an additive manufacturing technique that can be used to make the near-net-shape metal parts. M2 is a high-speed steel widely used in cutting tools, which is due to its high hardness of this steel. Conventionally, the hardening heat treatment process, including quenching and tempering, is conducted to achieve the high hardness for M2 wrought parts. It was debated if the hardening is needed for additively manufactured M2 parts. In the present work, the M2 steel part is fabricated by SLM. It is found that the hardness of as-fabricated M2 SLM parts is much lower than the hardened M2 wrought parts. The characterization was conducted including X-ray diffraction (XRD), optical microscopy, Scanning Electron Microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) to investigate the microstructure evolution of as-fabricated, quenched, and tempered M2 SLM part. The M2 wrought part was heat-treated simultaneously with the SLM part for comparison. It was found the hardness of M2 SLM part after heat treatment is increased and comparable to the wrought part. Both quenched and tempered M2 SLM and wrought parts have the same microstructure, while the size of the carbides in the wrought part is larger than that in the SLM part.

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