Energy Dispersive X-ray Diffraction Method Research Articles

Novel bulk triaxial residual stress mapping in an additive manufactured bridge sample by coupling energy dispersive X-ray diffraction and contour method measurements

A novel approach for determining triaxial residual stress states by coupling energy dispersive X-ray diffraction and contour method measurements is provided and validated in a Ti‐5Al‐5V‐5Mo‐3Cr additive manufactured (AM) bridge sample. Synchrotron X-ray diffraction (SXRD) can provide relatively fine spatial resolution (on the order of 10–100 µm) for mapping 3D elastic strain fields within a sample. However, for samples with dimensions larger than one or two centimeters the path length can get prohibitive as both constant wavelength and energy dispersive SXRD are based upon transmission measurements. As an example, for a plate-like sample geometry where the thickness is limited (less than a centimeter) it is trivial to measure the longitudinal and height direction elastic strain components with excellent in-plane spatial resolution (∼100 µm) and a somewhat lower through-thickness resolution (10–15 times larger) but obtaining the through thickness component is often not possible as the beam path must be parallel to one of the large dimensions of the plate. While small samples of low Z-number alloys (e.g., Ti or Al) allow determination of the three elastic strain components, this is often not the case for higher Z alloys (e.g., Fe or Ni) or large samples where some strain components can be indeterminable. To overcome these limitations, this work applies a combination of synchrotron X-ray diffraction and the contour method (a mechanical relaxation technique), to determine the triaxial stress state. This novel combination is demonstrated and validated in a relatively small additive manufactured sample where all three orthogonal strain components are accessible via X-ray diffraction for stress determination. The paper also explores methods for determining the strain-free lattice parameter, typically obtained from a small stress-free reference sample. This work shows that a small size AM sample is not stress free, producing unreliable magnitudes of strain and stress. Instead, a strain-free lattice parameter is determined using residual stress equilibrium conditions, which gives consistent strain and stress trends for both X-ray diffraction (alone) and the new diffraction-contour coupling technique. This demonstrates that the coupling technique can be confidently applied to samples to determine stress when path length (size or Z-number) prohibit determination of three orthogonal strain components via diffraction.

Optimisation and analysis of jet impingement erosion behaviour of composite titanium based ENi-P coated naval steel (AH36)

ABSTRACT This paper aims to address the impact of jet impingement on nano titanium-based ENi-P composite coatings deposited through electroless deposition on AH36 steel through Taguchi design of experiments. L9 Taguchi DOE was utilised to synthesise nine coatings by varying the four process parameter combinations suggested by the technique. Jet impingement combined with AFS 50/70 quartz sand erosion experimental run was conducted on the acidic, alkaline and nine ENi-P-TiO2 composite coatings administered through a waterjet erosion tester. The influence of C14-SB type Zwitterionic surfactant and nano TiO2 were discussed along with temperature and bath pH to achieve better resistance against the jet impingement on the surface of the coatings. Analysis of variance, the S/N ratio, and interaction plots were used to determine the optimal bath input parameters to deliver the least weight loss from the erosive environment and identify its use in the marine environment. The proposed optimal coating was validated using a confirmation test, and the weight loss was reduced by more than 35% compared to the initial condition parameter (A2B2C2D2). In addition to mechanical properties, the quality of the deposits was analysed through morphological and chemical composition probed through scanning electron microscope, energy dispersive X-Ray analysis and powder X-Ray diffraction methods. As a result, the Composite Modified Resilience (CMR) value of ENi-P-TiO2 optimal coating was improved by over 41.17%, and its corresponding weight loss was reduced to 35% compared to the initial condition. This experiment paves the way for further study on electroless deposits and their characteristics on AH36 steel generally used for shipbuilding in commercial ships, naval, and marine associated defence applications.

Effect of Mg addition on microstructure and mechanical properties of AlSi12 alloy produced by high-pressure casting method

PurposePaper aims to an alloy development study was carried out to increase the mechanical properties of cylinder heads.Design/methodology/approachAlSi12 alloys are used to manufacture the compressor head cylinder by high-pressure casting for easy casting and superior properties. Therefore, 1.1%, 2.4% and 3.1% Mg were added to AlSi12. The microstructures of the produced samples were characterized by optical microscope, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction methods. Hardness and tensile tests as well as Charpy impact tests were performed. Wear tests were also carried out on the pin-on disc tester, and then the wear performance was examined on the tester, which simulates the actual operating condition.FindingsAlSi12 has primary Si and eutectic Si in the Al matrix. However, alloys of Mg with AlSi12 have other intermetallics such as Mg2Si and ß-Fe, as well as primary Si and eutectic Si. Hardness and tensile strength as well as improved wear performance with increased Mg content.Originality/valueIn this study, wear performance test to simulate the operation of the cylinder head produced by high pressure casting from AlSi12 alloy moreover tensile test, hardness test and impact test were performed. Therefore, in this study, the wear performance of the compressor head produced by high-pressure casting method by adding three different amounts of Mg to AlSi12 alloy was investigated.

Characterization of residual stresses in fiber metal laminate interfaces – A combined approach applying hole-drilling method and energy-dispersive X-ray diffraction

Fiber metal laminates (FMLs) can be manufactured by direct bonding of fiber reinforced plastics (FRP) and metals using advanced manufacturing approaches, e.g., the prepreg-press-technology. Such materials gain high interest in lightweight applications as they benefit from the superior characteristics of both materials. However, residual stresses are induced in the manufacturing process mainly due to the difference in thermal expansion coefficients between FRP and metal. These residual stresses can lead to the delamination at the transition zone/ interface between FRP and metal and, thus, detrimentally affect the structural integrity and the durability of the FML structure.The objective of the present work is to introduce reliable experimental approaches to accurately measure the distribution of residual stresses across the thickness of the FML, with a special focus on the interface between metal and FRP. Symmetric FMLs with a specific stacking sequence of FRP/steel/FRP are designed and fabricated for residual stress analysis using different approaches, i.e., relaxation and diffraction methods, as well as for results comparison and validation purposes. The incremental hole drilling method (IHD) is used to determine the residual stresses across the thickness of the FMLs. By choosing FRPs with a relatively small thickness, a reliable measurement using IHD can even be achieved across the transition zone between FRP and metal. The energy-dispersive X-ray diffraction method (ED-XRD), as an advanced non-destructive approach, is employed for in-depth residual stress measurement in the metallic part of the FMLs. Each measurement method is characterized by its own advantages, intrinsic limitations as well as uncertainty sources. The obtained results give confidence that both methods are able to assess the qualitative distribution as well as the absolute magnitudes of residual stresses in the FMLs. Based on the approach detailed the reliability of the two measurement methods is cross-validated.

Effect of Bending Process on Microstructure, Mechanical Properties and Crack Formation of 5% Ni Steel

The 5% Ni steel is often used to make steel storage tanks to store liquefied natural gas (LNG). Herein, the microstructure and mechanical properties of 5% Ni steel samples during bending were studied through combining scanning electron microscopy, energy dispersive spectroscopy, optical microscopy, X-ray diffraction, and electron backscattered diffractometer methods with tensile tests. The outer and inner arcs underwent tensile and compressive stress, respectively, resulting in a severely deformed microstructure with a high density of dislocation, improving both the tensile and yield strengths. The ductility of the 5% Ni steel samples decreased significantly after bending due to the work hardening and dislocation accumulation. During bending, the shear bands occurred at the surface or subsurface, which were caused by strain localization. Amounts of “harder” grains with high TF and more orange and red KAM areas with high local strain at the outer and inner arcs produced a greater stress concentration than that of the mid-thickness, which can induce crack initiation and propagation due to the large deformation during bending.

Investigation of the Tracking and Erosion Resistance of a Ceramifiable Filler System for Silicone Rubber Composites

Improving the tracking and erosion resistance of silicone rubber (SiR) is of great significance to outdoor SiR insulators. In this work, a feasible method to enhance the antitracking performance of SiR by a ceramifiable system is investigated. Through scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), and other characterization methods, the mechanism that aluminum hydroxide (ATH) and low-melting glass (LMG) powder synergistically improve the tracking resistance of SiR is proposed. In this ceramifiable system, ATH plays a role in absorbing heat and serves as a precursor under the synergy with LMG, which promotes the formulation of dense mullite ceramic layer on the surface of SiR at the high temperature generated by dry band arc discharges, thereby the internal SiR is protected from degradation. Hydrophobicity and mechanical properties of ATH/LMG/SiR composites are also investigated, revealing that ATH/LMG improves the mechanical properties and hydrophobicity compared with one filler filled with the same amount. The ceramifiable system exhibits a good effect that the antitracking performance, mechanical properties, and hydrophobicity of SiR composites are improved at the same time. This system provides a new method for the research of antitracking SiR materials applied in outdoor SiR insulators.

Experimental Investigation on Isothermal Sections at 1273 and 1473 K in the Co–Ti–W System

The microstructures of 25 annealed alloys and XRD patterns of partial critical alloys in the Co–Ti–W system were investigated by using scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS) and X-ray diffraction (XRD) methods. The isothermal sections at 1273 and 1473 K of the Co–Ti–W system were established. Five three-phase regions and five two-phase regions at 1273 K and eight three-phase regions and two two-phase regions at 1473 K were experimentally determined. The maximum solubilities of W in Co3Ti, αCo2Ti, βCo2Ti and CoTi were determined to be ∼7.9 at%, ∼1.5 at.%, ∼5.9 at.% and ∼1.8 at.% at 1273 K, respectively. The maximum solubilities of Ti in Co7W6 and Co3W were determined to be ∼11.9 at.% and ∼15.2 at.% at 1273 K, respectively. The compound Co3Ti with L12 crystal structure was found to be stable at 1473 K in the Co–Ti–W system owing to the addition of W element, which confirmed that W can improve the stability of γ′ with L12 crystal structure in the Co-based superalloys. The composition range of W in Co3Ti was measured to be ∼7.4–10.4 at.% at 1473 K. In addition, the maximum solubilities of Ti in Co7W6 and W in βCo2Ti and CoTi were ∼15.4 at.%, ∼7.6 at.% and ∼3.1 at.% at 1473 K, respectively. No ternary compounds were found in the Co–Ti–W system at 1273 and 1473 K.

Chitosan functionalized with N,N-(2-aminoethyl)pyridinedicarboxamide for selective adsorption of gold ions from wastewater

The recovery of gold from wastewater has always been a research hotspot. Here, a novel chitosan-based adsorbent (CS-DPDM) was successfully synthesized by functionalizing chitosan with (N, N-(2-aminoethyl))-2,6-pyridinedicarboxamide. The adsorbent was analyzed by fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H NMR), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and zeta potential method (Zeta). To investigate the adsorption performance of CS-DPDM for Au(III), the effects of pH, temperature, adsorption time and initial concentration were discussed. The maximum adsorption capacity of CS-DPDM for Au(III) at pH 5.0 is 659.02 mg/g at 318 K. The adsorption is a spontaneous endothermic behavior, and the adsorption process follows the quasi-second-order kinetic and Langmuir isotherm models, indicating that a single layer of chemical adsorption may have occurred on the surface of the adsorbent. The competitive adsorption and repetitive experiments show that CS-DPDM has considerable selectivity and reusability for Au(III). X-ray photoelectron spectroscopy (XPS) results show that N and O functional groups adsorb Au(III) on the surface of CS-DPDM through electrostatic, chelation and reduction. These results indicate that CS-DPDM has broad application prospects in recovering gold ions from aqueous solutions.

Sealing performance of tempered vacuum glazing with silver oxide system low melting solder

In this paper, the safe sealing temperature range of tempered glass was determined to be no more than 300 °C by experiments. On this basis, the feasibility of silver oxide system low melting solder (SOSLMS) used in tempered vacuum glazing (TVG) sealing was explored by sealing strength experiment, scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and other test methods. The results of sealing strength experiment showed that the bonding strength of the sealing layer was inversely proportional to the sealing temperature. The bonding strength of the sealing layer in the range of 260 °C–290 °C met the standard requirements (not less than 0.6 MPa) except for the failure of the sample sealing at 300 °C. The observation results of SEM showed that when the sealing temperature was 260 °C and 270 °C, the solder layer had uniform fusion and dense structure, and the sealing layer was tightly bonded. With the increase of sealing temperature, the solder layer began to produce large holes, and there was obvious open gap between solder layer and glass substrate after stretching. The analysis results of EDS showed that the Ag and V elements all diffused into the glass at each sealing temperature, the difference of diffusion concentration and distribution was not significant. The analysis results of XRD showed that when the sealing temperature was in the range of 260 °C–270 °C, there was no crystallization phenomenon in the SOSLMS. When the sealing temperature was in the range of 280 °C–300 °C, Ag2VO2PO4 crystals began to precipitate, and with the increase of temperature, the higher the crystallinity was, the greater the crystal content was. In conclusion, in the range of 260 °C–270 °C, the SOSLMS showed good sealing performance, which was suitable for TVG sealing.

Experimental investigation and thermodynamic description of the Fe–Mo–Zr system

The phase relations at 1273 K and liquidus surface projection of the Fe–Mo–Zr system were investigated by means of electron probe micro-analyzer (EPMA), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD) methods. The composition range of C14 Laves phase was determined at 1273 K. The maximum solubility of Mo in C15–Fe2Zr, Mo in Fe23Zr6, Fe in C15–Mo2Zr and Zr in μ phase is about 4.8, 0.6, 17.7 and 4.6 at.% at 1273 K, respectively. The isothermal section at 1273 K of the Fe–Mo–Zr system on the whole composition ranges was constructed using 30 annealed alloys. In the liquidus surface projection, the primary solidification phase regions of bcc(Fe), C15–Fe2Zr, C14, μ, R, σ, bcc(Zr), C15–Mo2Zr and bcc(Mo) were experimentally confirmed using 31 as-cast alloys. Based on the experimental data in literature and the present work, the Fe–Mo–Zr system was optimized using CALPHAD method, and a set of self-consistent reliable thermodynamic parameters was obtained.

Segregation in squeeze casting 6061 aluminum alloy wheel spokes and its formation mechanism

Segregation can seriously damage the mechanical properties of the aluminum alloys. 6061 aluminum alloy wheel spokes were prepared by squeeze casting. To investigate the formation mechanism of segregation, the microstructure of the alloy was observed using scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction and electron microprobe analysis methods. The Gibbs energy of each phase during solidification was calculated by JMatPro. Results show that the segregation phases in the R-joint of the wheel spokes are mainly composed of Mg2Si, β-AlFeSi and Al5Cu2Mg8Si6 intermetallics. During the solidification of the 6061 aluminum alloy wheels, Mg2Si and α-AlFeSi phases precipitate in the mushy zone at first. With the decrease of temperature, α-AlFeSi transforms into β-AlFeSi, while Al5Cu2Mg8Si6 precipitates from the solid-state aluminum alloy after solidification. Segregation at the R-joint of wheel spokes is mainly caused by insufficient cooling, so the cooling during alloy solidification should be enhanced to avoid segregation.

Sorption of Pt(IV) ions on poly(m-aminobenzoic acid) chelating polymer: Equilibrium, kinetic and thermodynamic studies

In this work, poly(m-aminobenzoic acid) (PABA) chelating polymer was synthesized and its sorption behaviors for Pt(IV) ions have been investigated. The PABA polymer was prepared by the reaction of m-aminobenzoic acid with ammonium peroxydisulfate. Fourier transform-infrared spectroscopy (FT-IR), thermal analysis (TG and DTA), field emission-scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and surface porosity analytical methods were used in the characterization of the polymer. The FE-SEM images showed that the particles of the synthesized PABA polymer were about 2–10 μm. The PABA polymer is thermally stable up to 320 °C. The zero charge point of the polymer was found at pH 3.50. Batch adsorption experiments were used to examine the effects of pH, initial Pt(IV) concentration, contact time and temperature. The best adsorption values were obtained at pH 4, in which is above the zero charge point of the polymer. The equilibrium, kinetics and thermodynamics of Pt(IV) adsorption on the PABA polymer were examined. The Pt(IV) maximum adsorption capacity of the polymer is 2362 μg/g. The adsorption kinetic data fitted best to pseudo-second order kinetic model. The calculations with intra-particle diffusion and the Elovich models showed that the adsorption was controlled by intra-particle diffusion and chemisorption. The adsorption data fitted well to the Langmuir isotherm. It was found that the adsorption followed the pseudo-second-order kinetic model. In the thermodynamic calculations, the Gibbs free energies (ΔG°: (−10.98)–(−17.38) kJ/mol), the enthalpy (ΔH°:70.07 kJ/mol) and the entropy (ΔS°: 215.3 kJ/mol) change values of the adsorption were calculated. The column adsorption–desorption and reusability studies of the PABA polymer were also performed. The results showed that Pt(IV) sorption on the PABA polymer is endothermic and chemical adsorption process which is governed by both ionic interaction and chelating mechanisms.

Evaluation of high-temperature pyrolysis and CO2 gasification performance of bituminous coal in an entrained flow gasifier

This study used an entrained flow gasifier to assess the pyrolysis and gasification performance of Bangladeshi Barapukurian bituminous coal. The pyrolysis and CO2 gasification were conducted at temperatures of 1000°C–1400 °C under atmospheric pressure. The carbon conversion, syngas yield and pollutant emissions of coal using two different particle size of 90–106 and 250–300 μm have been analysed under CO2 concentration of 10–80 vol%. Solid residue (char/ash) was analysed by using scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX) and X-ray diffraction (XRD) methods. Results show that the release of volatile matter increases up to the temperature of 1200 °C. However, the temperature needs to increase at 1400 °C for the complete carbon conversion. Based on the CO/H2 ratio, syngas conditioning is required while using a temperature of 1200 °C or above, especially over the stoichiometric CO2 concentrations. Considering the heating value of syngas for power generation, the use of CO2 should be limited to less than 20% at a temperature of 1200–1400 °C. Particle size is important for carbon conversion but there is no significant impact on the heating value of syngas. Installation of the syngas cleaning system is required to drop the pollutants emission from the ppmv range to the ppbv range.

Effects of residual stress and plastic strain on hydrogen embrittlement of a stretch-formed TRIP-aided martensitic steel sheet

Hydrogen assisted cracking on hemispherically-stretch-formed specimens of transformation induced plasticity-aided martensitic steel was investigated. Hydrogen charging induced cracking around the foot of the impression formed on the steel sheet, and the cracks propagated along the radial direction toward the hillside and the plains. Distributions of stress, plastic strain and volume fraction of retained austenite were analyzed employing the energy-dispersive X-ray diffraction method utilizing the synchrotron X-ray radiation at SPring-8. It was notable that the crack initiation took place in the region where the measured tensile stress was the highest. Influences of plastic strain and resulted martensitic transformation were also suggested.

Study of (AgxCu1−x)2ZnSn(S,Se)4 monograins synthesized by molten salt method for solar cell applications

The open circuit voltage (VOC) deficit of Cu2ZnSn(S,Se)4 (CZTSSe) kesterite solar cells is higher than that of the closely related Cu(InGa)Se2 solar cells. One of the most promising strategies to overcome the large VOC deficit of kesterite solar cells is by reducing the recombination losses through appropriate cation substitution. In fact, replacing totally or partially Zn or Cu by an element with larger covalent radius one can significantly reduce the concentration of I–II antisite defects in the bulk. In this study, an investigation of the impact of partial substitution of Cu by Ag in CZTSSe solid solution monograins is presented. A detailed photoluminescence study is conducted on Ag-incorporated CZTSSe monograins and a radiative recombination model is proposed. The composition and structural quality of the monograins in dependence of the added Ag amount are characterized using Energy Dispersive X-ray Spectroscopy and X-Ray Diffraction method, respectively. The Ag-incorporated CZTSSe monograin solar cells are characterized by temperature dependent current-voltage and electron beam induced current methods. It was found, that low Ag contents (x ≤ 0.02) in CZTSSe lead to higher solar cell device efficiencies.

A joint experimental and theoretical study on the structural, electronic and optical properties of malayaite and Chromium‐doped malayaite structures as pigments

Ceramic pigments due to their properties of thermal stability and suitable optical characteristics are widely used in industries. Hence, the theoretical study of pigments based on density functional theory (DFT) is valuable to predict the structural, electronic, optical and especially colorimetric properties of them. We have synthesized the malayaite (CaSnSiO5) and chromium-doped malayaite with variable chromium concentration by the conventional ceramic route. Also, we have modeled these structures and performed DFT/TDDFT calculations by using the Quantum ESPRESSO package and YAMBO code. We studied the structural, electronic and optical properties of the structures. The role of chromium in the malayaite structure is determined by Energy Dispersive Spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy methods. For the Cr-doped samples, it is shown that main XRD and Raman peaks have been shifted and it has explained the reason for the resonance-enhancement of vibrational modes of the samples. In the electronic property calculations, it is indicated that the gap and Fermi energies of the theoretical samples with increasing the doping concentration are decreased. In the optical properties section, UV–Vis spectroscopy and CIE L*a*b* colorimetry methods are used and the correspondence of the absorption spectra and colorimetric results for all samples is shown. Also, the gap energy of the experimental samples is compared to the theoretical samples. The results indicate the advantage of the DFT method for ceramic pigments.

Titanium carbide’s effects on coatings formed on D16T aluminum alloy by plasma electrolytic oxidation

Purpose The preferable concentration of titanium carbide was optimized and added as an additive to the micro-arc oxidation electrolyte to produce a high corrosion-resistant coating on D16T aluminum alloy. Design/methodology/approach Ceramic coatings were deposited on D16T aluminum alloy by plasma electrolytic oxidation in alkaline silicate electrolytes with micron titanium carbide particle suspending at different concentrations. Influences of additive concentration on morphology, elemental and phase composition and corrosion resistance of doped PEO coatings were evaluated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and electrochemical methods, respectively. Findings Results revealed that suspending titanium carbide additives incorporated into ceramic coatings through discharging channels and chemically transformed into amorphous stage. The content of titanium in the doped coatings increased with the increasing concentration of suspending micron additive. Compared with the coating without particle addition, the corrosion resistance of the coating produced in 8 g/L titanium carbide suspension increased more than 20 times. The result indicated that the incorporation of titanium into the PEO coatings formed on the D16T aluminum alloy could effectively improve the corrosion resistance. Originality/value The mechanism of corporation of TiC and the mechanism of improving the corrosion resistance of the coating were proposed.

Investigation of Creep Behavior of CNT Reinforced Ti6Al4V Under Dynamic Loads

This study investigates the effects of addition of Carbon nanotube (CNT) at different volume ratios (0.5- 5%) into Ti6Al4V matrix by mechanical alloying in terms of the density, microstructure, hardness and creep under dynamic load. As a result of the good bonding of carbon nanotubes powders with the main matrix, Ti-6Al-4V/CNT composites have experienced change both in microstructure and mechanical properties (such as hardness, density) and, correspondingly, qualitatively creep behaviour of Ti-6Al - 4V matrix alloy has been improved compared to the lean one. The density of CNT reinforced Ti6Al4V composites sintered at 1300and#176;C for 3h decreases with increasing CNT content. The hardness tests indicated that the hardness of composites increased with CNT addition. In addition, although creep strain is decreased continually with CNT content until 5%, creep life increased with increasing CNT content until 4% of CNT but decreased above 4%. After sintering at 1300 and#176;C under vacuum for 3 hours the density of the composite material reached to a level of 98.5 %, the microhardness to 538 HV and the creep behaviour was improved. The characterization of Ti6Al4V / CNT composites after mechanical alloying was carried out using scanning electron microscopy (SEM), energy dispersive x-rays spectroscopy (EDS) analysis and X-ray diffraction (XRD) methods. Although Ti–6Al–4V alloys are used as biomaterial, this study aimed at using MWCNTs containing Ti-6Al-4V composites at high temperature applications. Because MWCNTs reinforced Ti-6Al-4V composites are cheaper and have lower weight than the other materials used in this kind of applications.

Investigation of Creep Behavior of CNT Reinforced Ti6Al4V Under Dynamic Loads

This study investigates the effects of addition of Carbon nanotube (CNT) at different volume ratios (0.5- 5%) into Ti6Al4V matrix by mechanical alloying in terms of the density, microstructure, hardness and creep under dynamic load. As a result of the good bonding of carbon nanotubes powders with the main matrix, Ti-6Al-4V/CNT composites have experienced change both in microstructure and mechanical properties (such as hardness, density) and, correspondingly, qualitatively creep behaviour of Ti-6Al - 4V matrix alloy has been improved compared to the lean one. The density of CNT reinforced Ti6Al4V composites sintered at 1300and#176;C for 3h decreases with increasing CNT content. The hardness tests indicated that the hardness of composites increased with CNT addition. In addition, although creep strain is decreased continually with CNT content until 5%, creep life increased with increasing CNT content until 4% of CNT but decreased above 4%. After sintering at 1300 and#176;C under vacuum for 3 hours the density of the composite material reached to a level of 98.5 %, the microhardness to 538 HV and the creep behaviour was improved. The characterization of Ti6Al4V / CNT composites after mechanical alloying was carried out using scanning electron microscopy (SEM), energy dispersive x-rays spectroscopy (EDS) analysis and X-ray diffraction (XRD) methods. Although Ti–6Al–4V alloys are used as biomaterial, this study aimed at using MWCNTs containing Ti-6Al-4V composites at high temperature applications. Because MWCNTs reinforced Ti-6Al-4V composites are cheaper and have lower weight than the other materials used in this kind of applications.

A sensitive determination of tramadol using a voltammetric platform based on antimony oxide nanoparticles

A novel voltammetric platform has been developed with nanoparticles of antimony oxide (Sb2O3NPs) and multiwalled carbon nanotubes (MWCNTs). Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction method (XRD) were used for the characterization of the novel composite material (Sb2O3NPs/MWCNTs). The proposed composite material was used for the modification of a glassy carbon electrode (GCE). The proposed modified electrode (Sb2O3NPs/MWCNTs/GCE) was applied to the electro-oxidation of tramadol (TRA). A high catalytic activity was observed towards the oxidation of TRA using the proposed voltammetric platform. In addition, the electrode presented a large enhancement in the peak current when compared to several other electrodes. A selective detection of TRA was also observed in the presence of paracetamol (PAR) with large peak to peak separation. The peak current exhibited a linear dependence on the concentration of TRA in a dynamic range of 4 × 10−8–3.0 × 10−5 with a detection limit of 9.5 × 10−9 M. A successful procedure of the determination of TRA in pharmaceuticals makes the novel voltammetric platform of high interest for monitoring its therapeutic use.