X-ray Diffraction Profile Analysis Research Articles

Dislocation Structure in Hot Deformed Al-Zn-Mg Alloy by X-ray Line Profile Analysis.

The microstructure of extruded Cu-free Al-Zn-Mg alloy is studied. Hot torsion tests are performed on a Cu-free Al-Zn-Mg alloy to investigate the effect of large strain deformation on the dislocation behavior. The dislocation structure is characterized by X-ray diffraction profile analysis, and the effective stress-strain curves are obtained by hot torsion tests. The dislocation density at low deformation temperature is found to be higher than that at high deformation temperature. The dislocation density of the alloy increases gradually up to ε = 1 with increasing strain and does not change significantly during further deformation.

X-ray diffraction (XRD) profile analysis of pure ECAP-annealing Nickel samples

X-Ray Diffraction (XRD) profile of pure equal channel angular pressing (ECAP)-annealing nickel samples has been thoroughly investigated for studying the material structures changes that imply to the mechanical behavior. Nickel-based material can be used for several applications such as biomaterial, gear, and some part of the instrument at nuclear facilities, which require high-grade standard material properties. ECAP is one kind of severe plastic deformation (SPD) techniques to obtain excellent mechanical properties without adding another element. However, the ECAP process generates metastable structures due to some mismatch structure and inhomogeneous stress within the material. This problem can usually be resolved by annealing after the ECAP process. In this article, pure Nickel was processed by ECAP at 423 K for two passes. The post-ECAP annealed will be carried out at the temperature range from 298 K until 1373 K. The microhardness test results indicate that the ECAP process increases the microhardness significantly, which remains stable after annealing until 773 K. At higher annealing temperature, the mechanical properties will drop suddenly and reach the microhardness value of pure pre-ECAP Nickel. This behavior could be explained clearly by the XRD data analysis result, which shows similar behavior structure changes. XRD data initially show peak shifting to lower 2θ value, which indicates an expansion to a higher lattice parameter, then at the higher annealing temperature, the diffraction peaks split gradually. This peak splitting could be indexed as pure pre-ECAP Ni peaks, which could be related to the drop of the microhardness value.

Structural and physical parameters of sol-gel spin coated ZnO thin films: Effect of sol concentration

Zinc oxide thin films are deposited by sol–gel spin coating on glass substrates for varying sol concentrations and the effect is studied on a range of structural and physical parameters which are determined by X-ray diffraction and X-ray peak profile analysis. The diffraction peaks confirms the formation of ZnO with hexagonal wurtzite phase. The film with highest sol concentration shows preferred c-axis orientation. The crystallinity of the films increases with increase in concentration of the sol. The X-ray peak broadening analysis was employed to estimate the physical parameters such as strain, stress and energy density corresponding to major diffraction peaks by the Williamson-Hall (W-H) method with three different models namely uniform deformation model, uniform stress deformation model and uniform deformation energy density model. To the best of our knowledge studies of ZnO thin films deposited with various sol concentrations using these models have not been reported. The deposited ZnO thin films may be used in solar cells to enhance their efficiency.

Photocatalytic and photoluminescent properties of a system based on SmPO4 nanostructure phase

In the present work, we investigate the structural, microstructural, vibrational, photocatalytic and luminescence properties of the system SmPO4 thermally treated at 900 °C. Polycrystalline sample was elaborated using a coprecipitation method. The sample was then characterized using different techniques such as X-ray diffraction, Scanning electron microscopy, Infrared spectroscopy, Raman spectroscopy and photoluminescence analysis under UV excitation. X-ray diffraction profile analysis showed that the pure monoclinic phase P21/n was observed. The scanning electron microscopy experiments showed a homogeneous distribution of morphologies and indicated that SmPO4 was in nano-sized particle. Attributions of Raman and FTIR vibrational modes were proposed. For the photocatalytic activity, UV–visible spectrophotometer has been used to analyze the evolution of photodegradation of rhodamine B (RhB). The photocatalytic degradation of rhodamine B in the presence of SmPO4 photocatalyst has been studied for the first time. Photoluminescence (PL) properties of SmPO4 nanoparticle under UV excitation has been reported and investigated.

The Impact of the Ionic Cross-Linking Mode on the Physical and In Vitro Dexamethasone Release Properties of Chitosan/Hydroxyapatite Beads.

In this study, the effect of the ionic cross-linking mode on the ability to control physical properties and in vitro release behavior of the dexamethasone (DEX) drug from chitosan (CS) and chitosan/hydroxyapatite (CS/HA) beads was investigated. CS solutions without and with HA and DEX were dripped into two coagulation solutions, prepared with a non-toxic ionic crosslinker (sodium tripolyphosphate, TPP) and distilled water, one at pH = 9.0 and other at pH = 6.0. Optical microscopy (OM) and scanning electron microscopy (SEM) results showed changes on the surface topology of the beads, with a reduction of roughness for beads prepared at pH = 6.0 and an increase for the one prepared at pH = 9.0. The diameter and sphericity of the beads prepared at pH = 6.0 proved more uniform and had a larger pore size with a good interconnectivity framework. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) suggested a higher crosslinking degree for beads prepared at pH = 6.0, corroborated by X-ray diffraction profiles (XRD) analysis that indicated a decrease in the crystalline structure for such beads. In in vitro drug release data, all beads presented a sustained release during the studied period (24 h). The drug release rate was affected by the pH of the coagulation solution used in the preparation of the beads. The in vitro kinetics of the release process was of the Peppas–Sahlin model, controlled by both diffusion and relaxation of polymer chains or swelling (anomalous transport mechanism). Our results suggest that DEX-loaded CS/HA beads, crosslinked in TPP coagulation solution at pH = 9.0, led to a decrease in the DEX release rate and prolonged the release period. Thus, this composition might have prospective as a functional material for bone and cartilage tissue engineering.

Synthesis, characterization and luminescence properties of manganese phosphate Mn3(PO4)2

Abstract A great deal of research has concerned the study of the photoluminescent properties of new materials. These studies are motivated by many potential applications in a wide variety of fields such as optical telecommunications, lasers, lighting, radiation detection and photovoltaic. In the present work, we investigate the structural, microstructural, vibrational and luminescence properties of the system Mn3(PO4)2 as a new luminescent material. Polycrystalline sample was elaborated using a coprecipitation technique. The sample was then characterized using X-ray diffraction, scanning electron microscopy, Infrared spectroscopy and luminescence analyses. X-ray diffraction profile analyses showed that the monoclinic crystal cell, was observed. The scanning electron microscopy experiments showed a homogeneous distribution of morphologies and crystallite sizes. The functional groups were indicated by Fourier transform infrared spectroscopy. The Luminescence experiments were performed under UV–visible light irradiation (364 and 633 nm). The integrated intensity of luminescence showed a maximum value in the presence of the powder Mn3(PO4)2.

In-situ High-Resolution Transmission Electron Microscopy and X-ray Diffraction Studies on Nanostructured β-SiC and Its Promising Feature for Photocatalytic Hydrogen Production

The ruin of energy and environmental pollution has led to the pursuit of novel technologies for green energy productions. For hydrogen energy itself, the search for the photocatalytic-based nanostructured β-SiC is one of the main research focus during the last few years. Herein, we reported the successful magnesiothermic reduction at low temperature, i.e., 700 °C, using an argon gas tubular furnace to fabricate β-SiC with a particle size below 10 nm. The X-ray diffraction (XRD) data collection and Rietveld refinement showed the single phase of moissanite β-SiC formation having cubic structure with lattice constants of a = b = c = 4.3523(50) Å and α = β = γ = 90°. The formation of the nanostructured β-SiC was well confirmed by the high-resolution transmission microscopy (HRTEM) image. The equivalent crystallite size produced by the XRD profile analysis was 4.2(8) nm, and extracted from the HRTEM image was about 6 nm. The d-spacing for (111) plane met a reliable agreement between the XRD and HR-TEM data. The energy dispersive X-ray spectroscopy in scanning transmission electron microscopy (STEM-EDS) also brought a good capture for the nearly 50:50 concentration of Si:C in our sample. Furthermore, in-situ heating experiments via HR-TEM were also conducted. In brief, carbon nanolayers were initiated on the surface of the nanostructured β-SiC. All these fine-tuned crystallographic properties assigned the as synthesized β-SiC to be the promising candidate for photocatalytic hydrogen production.

Structural Study of Novel Nanocrystalline fcc Ti-Ta-Sn Alloy

This report discussed the microstructural features of fcc Ti-13Ta-6Sn alloy synthesized using mechanical ball milling at 100 hours. The X-ray diffraction profile analysis was discussed using Rietveld, modified Williamson-Hall and Warren-Averbach methods. Two important conditions, high plastic deformation and nanocrystalline size range to satisfy the stable face-centered cubic (fcc) phase were achieved. The X-ray diffraction profile analysis and TEM images proved that the crystallite size and dislocation density of 6.6 nm and 1016 m−2, respectively.

Strengthening mechanisms of 2A14 aluminum alloy with cold deformation prior to artificial aging

The introduction of cold deformation prior to aging is an important strengthening method of aluminum alloy. However, it is unclear how many mechanisms of strengthening take effect, and how those mechanisms affect each other during aging process. In this paper, the precipitation kinetics parameters of θ′′ phase, θ′ phase in aging process after cold deformation were obtained by Differential Scanning Calorimeter（DSC）combined with JMA equation. Dislocation densities of the cold deformed specimens were successfully estimated from X-Ray Diffraction (XRD) profile analysis using the modified Williamson-Hall equation. A comprehensive quantitative model for the strengthening of 2A14 aluminum alloy due to precipitation strengthening, solid solution strengthening, grain/subgrain strengthening and dislocation strengthening was presented. The model revealed the evolution law of these four strengthening mechanisms during aging process, and predicted the combined effects and competitive relationship of four strengthening mechanisms on the yield strength of 2A14 aluminum alloys. The accuracy of the model prediction was verified through experiments when the cold deformations were smaller than or equal to 6% and can be used to design aging process of 2A14 aluminum alloy.

Structure and defect interaction mediated transport mechanism of mixed di-tri valent cation containing ceria-based Ionic conductors

The aim of this study is to investigate structure and electrical response of mixed di-tri valent cation containing Ce1-xHo0.1SrxO2-δ (x = 0.02–0.1) ionic conductor. The Rietveld analysis of X-ray diffraction profiles confirms the solubility limit of Sr2+ ions into ceria lattice upto x = 0.06 and the co-existence of secondary phase SrCeO3 afterwards. With the increase of Sr2+ ions into ceria, formation of defect cluster increases and concentration of free oxygen vacancies decreases. The composition x = 0.06 shows lowest conductivity due the highest association energy of defect clusters. The dielectric constant plays a crucial role for the formation of defect clusters and conductivities of the compositions. The presence of SrCeO3 and depletion of oxygen vacancies at grain boundary region enhance the grain boundary resistances. The dielectric constant of grain boundary region affects the grain boundary conductivity.

Crystalline Phase Analysis and Thermal Expansion Coefficient Calculation of Quartz-Sand/Corundum Composites

Quartz-sand/corundum composites have been successfully produced by a simple solid-state reaction approach. The composites with corundum weight fractions of 10%, 20%, and 30% were prepared through grinding mixtures of purified Indonesian quartz sand and commercial high purity corundum for a half-hour with an addition of 3% polyvinyl alcohol. The composites were shaped into discs and pressed prior to the sintering at 950 °C and 1050 °C to form compact ceramic composites. The crystalline phase verification within the samples was conducted by means of X-ray diffraction (XRD). The coefficient of thermal expansion (CTE) of the composites was semi-theoretically evaluated, after being taken into consideration the XRD data analysis results, by means of Halpin-Tsai formula. The detected major crystalline phases within the sintered samples, based on the XRD profiles analysis, were quartz-SiO2 and corundum-Al2O3. Meanwhile, the minor crystalline phases were wollastonite-CaSiO3 (below 7%) for all samples and cristobalite-SiO2 (around 1%) for the composite with 1050 °C sintering temperature. Generally, the addition of corundum into the quartz-sand/corundum composites reduced the CTE, having the value from 10.5 to 11.5 ppm/°C.

On the comparative assessment of ratcheting-induced dislocation density in 42CrMo4 steel by X-ray diffraction profile analysis and hardness measurement

ABSTRACTThe phenomenon of ratcheting occurs under the influence of non-zero mean stress during cyclic loading; it singificantly reduces the low cycle fatigue life of engineering structures. The present investigation deals with a detailed comparison on the estimation of dislocation densities in the 42CrMo4 steel induced by ratcheting using two different methods, i.e. X-ray diffraction (XRD) profile analysis and hardness. The dislocation densities in the ratcheted specimens were assessed using XRD profile analysis following the modified Williamson–Hall method as well as hardness measurements following the modified Nix and Gao model. The results showed that dislocation density increased in the ratcheted specimens as compared to the unratcheted ones and increase in accumulation of ratcheting strain was correlated with the increase in dislocation densities in the ratcheted specimens. It was established that both hardness and X-ray diffraction profile analysis methods can very effectively be used to assess the dislocation densities in the ratcheted specimens.

Dislocation, crystallite size distribution and lattice strain of magnesium oxide nanoparticles

The oxide of magnesium nanoparticles synthesized using sol-gel method and analysis of the structural properties was conducted. The functional groups of nanoparticles has been analysed by Fourier Transform Infrared Spectroscopy (FT-IR). Dislocations, average size of crystal, strain, stress, the energy density of crystal, crystallite size distribution and morphologies of the crystals were determined based on X-ray diffraction profile analysis. The morphological of the crystal was analysed based on the image resulted from SEM analysis. The crystallite size distribution was calculated with the contention that the particle size has a normal logarithmic form. The most orientations of crystal were determined based on the textural crystal from diffraction data of X-ray diffraction profile analysis. FT-IR results showed the stretching vibration mode of the Mg-O-Mg in the range of 400.11-525 cm−1 as a broad band. The average size crystal of nanoparticles resulted is 9.21 mm with dislocation value of crystal is 0.012 nm−2. The strains, stress, the energy density of crystal are 1.5 x 10−4; 37.31 MPa; 0.72 MPa respectively. The highest texture coefficient value of the crystal is 0.98. This result is supported by morphological analysis using SEM which shows most of the regular cubic-shaped crystals. The synthesis method is suitable for simple and cost-effective synthesis model of MgO nanoparticles.

Fabrication of electrospun Mn1−xZnxMoO4 (x = 2.5%, 5%, and 10% Zn) nanofibers: Microstructure parameters, surface morphology and Kramers-Kronig (KK) analysis

Electrospun Mn1−xZnxMoO4 nanofibers (x = 2.5%, 5% and 10%), have been prepared by controlling the Zn concentration of a polymeric solution followed by calcination. The effects of Zn doping on structural, morphological, chemical characterization, and optical properties of the manganese molybdate nanofibers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive analysis of X-rays (EDAX), BJH pore size and volume analysis, Fourier Transform Infrared (FTIR), and Reflectance spectrum in the wave length range of 200–1200nm. XRD studies revealed the diffraction peaks are mainly assigned to the orthorhombic structure of the MoO3 phase. The microstructural investigation of the calcinated nanofibers has been achieved from the size-strain plot (SSP) model using X-ray diffraction profile analysis. The SEM images exhibit Zn-doped manganese molybdate ceramic nanofibers with diameters ranged from 60 ± 10 to 90 ± 10nm after calcination at 400°C. The optical property of the prepared nanofibers was also proposed according to the Kramers-Kronig model.

Temperature effect on the structure and characteristics of ZnS-based quantum dots

The synthesis of zinc sulfide (ZnS) quantum dots (QDs) by microwave heating in a water-ethanol medium is proposed. The effect of the synthesis temperature (80 °C, 100 °C, 120 °C, and 150 °C) on the QD characteristics is examined. Based on the analysis of X-ray diffraction profiles the conclusion is drawn that the hexagonal ZnS phase of wurtzite type with an average nanocrystal size of 2.6-3.7 nm forms in the synthesized QDs. The nanocrystallite size is found to increase with the QD synthesis heating temperature. The analysis of X-ray absorption spectra (XANES) at the zinc K-edge indicates a higher crystallinity of the QD samples prepared at higher synthesis temperatures. The combined analysis of X-ray diffraction profiles, optical diffuse reflectance spectra, and X-ray absorption spectra implies the following possible QD structure: the pure hexagonal ZnS phase of wurtzite type in the bulk of nanoparticles and the amorphous ZnO phase in the surface layer of nanoparticles.

Increment of activity of Pd(OH)2/C catalyst in order to improve the yield of high performance 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (HNIW)

ABSTRACTCL-20 [2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (HNIW)] is a well-known high performance explosive. The reductive debenzylation of hexaazaisowurtzitane (HBIW) over supported palladium catalyst produces 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (TADB). The effects of precipitation conditions of Pd(OH)2 and the porosity of the activated carbon support on the activity of synthesized Pd(OH)2/C catalysts in the debenzylation of HBIW are investigated here. The activity of Pd(OH)2/C catalyst is considerably affected by the porosity of the activated carbon. The surface morphology of the synthesized catalysts is studied by X-ray diffraction (XRD) profile analysis and transmission electronic microscope (TEM). Metal dispersion of Pd(OH)2/C catalysts is changed by precipitation conditions of Pd(OH)2.

Luminescent properties under X-ray excitation of Ba(1−x)PbxWO4 disordered solid solution

A series of polycrystalline barium-lead tungstate Ba1-xPbxWO4 with 0 ≤ x ≤ 1 was synthesized using a classical solid-state method with thermal treatment at 1000°C. These materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Raman (FT-Raman) spectroscopy. X-ray diffraction profile analyses were performed using Rietveld method. These materials crystallized in the scheelite tetragonal structure and behaved as quasi ideal solid solution. Raman spectroscopy confirmed the formation of the solid solution. Structural distortions were evidenced in X-ray diffraction profiles and in vibration Raman spectra. The scanning electron microscopy experiments showed large and rounded irregular grains. Luminescence experiments were performed under X-ray excitation. The luminescence emission profiles have been interpreted in terms of four Gaussian components, with a major contribution of blue emission. The integrated intensity of luminescence reached a maximum value in the composition range x = 0.3–0.6, in relation with distortions of crystal lattice.

Dislocation Density of Plastically Deformed Oxygen-Free Copper

The dislocation density of plastically deformed oxygen free copper (OFC) was evaluated by X-ray diffraction profile analysis with synchrotron radiation. The modified Williamson-Hall and modified Warren-Averbach methods were applied to the analysis. The dislocation densities of OFC samples with compressive plastic strains of 1 % and 4 % were 5.1×1014 m-2 and 9.2×1014 m-2, respectively.

Dislocation density and mechanical threshold stress in OFHC copper subjected to SHPB loading and plate impact

The dislocation density and mechanical threshold stress (MTS) of oxygen-free high-thermal-conductivity (OFHC) copper loaded at strain rates in the range of 102 to 106s−1 were measured. Moderate-strain-rate (102 to 104s−1) experiments were performed using a Split Hopkinson Pressure Bar (SHPB). A steel collar was placed around each specimen to control the maximum loading strain. High-strain-rate (105 to 106s−1) experiments were carried out using a 57-mm-bore single-stage gas gun. The radial release effect was eliminated using the momentum trapping technique. The loaded samples were recovered, and the dislocation characteristics and dislocation density were determined by X-ray diffraction profile analysis. The fraction of the screw dislocation was found to decrease with increasing loading strain and strain rate. The dislocation density was found to lie between 1.8×1014 and 2.2×1015m−2. Quasi-static reload compression tests were performed on the recovered samples at room temperature. The mechanical threshold stress (or the flow stress at 0K) was obtained by fitting the reload stress–strain data to the MTS model. The results of analysis of the equivalent strain, mechanical threshold stress, and dislocation density measurements suggest that the relation between the mechanical threshold stress and the dislocation density can be described well by the Taylor relationship.

Estimation of microstructure and corrosion properties of peened nickel aluminum bronze

In this study, the effects of shot peening on the residual stress, microstructure and corrosion properties of nickel aluminum bronze were evaluated by using X-ray stress analyzer, X-ray diffraction profile analysis, transmission electron microscopy and electrochemical tests. Shot peening improved the hardness and compressive residual stress of the surface layer. A thin layer of nanometer-scaled domain formed at the top surface and the domain size raised constantly with depth until it reached nearly the value of matrix. The micro-strain and dislocation density dropped gradually with the increasing distance toward interior. Moreover, the samples treated by shot peening with different intensities all showed superior corrosion resistance than that of unpeened ones. However, further improving the peening density resulted in a poor corrosion performance, which was mostly ascribed to the increased surface roughness due to the raised deformation.