Diffraction Techniques Research Articles

Structural and dielectric features of (Bi0.5Na0.5)1−xBaxTiO3 lead-free ferroelectric ceramics: An approach to the phase diagram

(Bi0.5Na0.5)1−xBaxTiO3 lead-free ferroelectric ceramics were synthesized via the conventional solid-state reaction method. Structural and dielectric properties were investigated as a function of the doping concentration, considering x = 0, 2, 5, 8, 10, 12, 16, and 18 at. % Ba. The structural analyses were carried out from the x-ray diffraction technique, including the Rietveld refinement method, and Raman spectroscopy. Results confirmed the formation of the perovskite structure, revealing different crystalline symmetries, depending on the Ba2+ concentration: the single rhombohedral ferroelectric phase (R3c) for x = 0 and 2 at. %; coexistence of both rhombohedral ferroelectric (R3c) and tetragonal antiferroelectric (P4bm) phases for x = 5 at. % Ba; the single tetragonal antiferroelectric phase (P4bm) for x = 8 at. % Ba; coexistence of two tetragonal phases (antiferroelectric P4bm and ferroelectric P4mm) for x = 10 at. % Ba; and the single tetragonal ferroelectric phase (P4mm) for x = 12, 16, and 18 at. % Ba. The characteristics of the phases’ transition, investigated from dielectric analysis, revealed the presence of two dielectric anomalies, which indeed have been associated to different phases’ transitions, one of them showing relaxor-like characteristics. The obtained results offer new insights for a better understanding on the features of the phase diagram for the studied ceramic system, according to the different observed crystalline symmetries (ferroelectric and antiferroelectric) in a very wide doping concentration. In the light of the obtained results, a new phase diagram has been proposed considering a wider compositional range than those reported in the literature.

GEOTECHNICAL AND MINERALOGICAL CHARACTERISTICS OF LATERITIC SOIL AND LOCUST BEAN (PARKIA BIGLOBOSA) PODS ASH AS CONSTRUCTION SOIL

African locust bean (Parkia Biglobosa) has been in great demand and consequently yielding large amounts of the pods which could be a potential hazard to the environment. Converting the pods to ash that would be utilized as construction material is another way of handling them properly. The effects of the mineralogy of the soil on its geotechnical characteristics when the soil is treated with locust bean pod ash have been given very little attention. Therefore, this study considered the effects of locust bean pod ash (LBPA) and the mineralogy of lateritic soil on some geotechnical properties necessary for it to be used as subgrade or foundation soil. The determination of the chemical constituents of the LBPA was carried out using Atomic Absorption Spectrometer. The lateritic soil was characterized by identifying the clay minerals as well as non-clay minerals present in the soil using the x-ray diffraction technique and preliminary tests were also carried out to properly rate the soil. The soil was treated by applying dosages of LBPA 0 – 25% at intervals of 5% and the percentages were measured by weight of the dry soil. The tests conducted on the prepared soil samples with LBPA were specific gravity, consistency indices, compaction (British Standard Light), California bearing ratio and direct shear box test. The LBPA was found to be an acceptable pozzolanic material for the treatment of the lateritic soil. The lateritic soil was observed to belong to soil groups A-2-6(0) in the AASHTO and poorly graded sand (SP) in USCS ratings. It was also observed that the non-clay minerals present in the soil were quartz, feldspar and mica whereas the clay minerals present were kaolinite, iolite, vermiculite and chlorite which had a significant influence on the geotechnical characteristics of the soil. The specific gravity of the LBPA was relatively low and the additions of LBPA reduced the specific gravity of the soil. The consistency indices also dropped and subsequently increased with the further addition of LBPA. The increase in LBPA contents caused increments in the optimum moisture content while the maximum dry density and shear strength parameters reduced. The strength characteristics like the California Bearing Ratio of the lateritic soil improved by 173.91% at the addition of 5% LBSA content which was determined to be the optimum dosage.

Facile encapsulation of a cobalt complex inside the micropores of ZIF-8 through the bottle around the ship method: A novel heterogeneous catalyst for epoxidation of alkenes

A novel and stable heterogeneous catalyst for alkene epoxidation reaction, named as CoDMG@ZIF-8, has been synthesized by facile encapsulation of Co(III) complex i.e. [Co(DMGH)(DMGH2)Cl2] (abbreviated as CoDMG, DMGH2 denotes for dimethylglyoxime and DMGH denotes for dimethylglyoxime mono anion) inside the ZIF-8 micropores via a solvothermal process. Based on the results of fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) technique and field emission scanning electron microscopy (FE-SEM), it was observed that the catalyst has maintained the structure, crystallinity and morphology of the parent ZIF-8 as well. Furthermore, CHN, DRS (diffuse reflectance spectra), energy dispersive X-ray (EDX), induced coupled plasma (ICP-OES), thermal gravimetric (TGA) and nitrogen adsorption-desorption (BET method) analyses have confirmed the encapsulation of the CoDMG complex. The epoxidation reaction was performed using tert‑butyl hydroperoxide (TBHP) in CH3CN solvent in the presence of catalyst. By optimizing the reaction parameters, a total conversion of 96 % with 82 % selectivity towards the epoxide product, was achieved. It was found that both CoDMG complex and ZIF-8 exhibited lower efficiency individually, while the encapsulation of this complex inside the ZIF-8 micropores has resulted to superior activity. Finally, the epoxidation of various alkenes such as cyclohexene, 2-norbornene, α-pinene, styrene and 1-hexene under the optimized reaction condition, have been studied and the catalytic mechanism was also proposed.

The production system and structural characterization of CAMNi-xTIxO3 with x values ranging from 0.0 to 1.0 are investigated

In this work, we report the production of new composite perovskite manganite system CaMn ,Ti,O, with doping x = 0.25, 0.5 and 0.75, reaction sintering method solid state. Structural characterization was performed using the technique of X-ray Diffraction (XRD) and the Rietveld method, obtaining a tetragonal structure, with Prima spatial group (# 62) (a=5.3586a y a=5.2997A: b=7.5041 A y b=7.5526a; c+5.3l82& y c=5.3278A). In this paper takes the discussion on possible structural changes with changes in the system titanium CaMn, ,Ti,O,.

Effect of oxygen-ion implantation on the local electronic structures of strontium-titanate single crystals: An investigation using synchrotron-based x-ray diffraction and x-ray photoemission techniques

Effect of oxygen-ion implantation on the local electronic structures of strontium-titanate single crystals: An investigation using synchrotron-based x-ray diffraction and x-ray photoemission techniques

Investigation of structural, photo and thermoluminescence properties of YAGG:Ce nanogarnet for medical dosimetry application

Cerium-doped yttrium aluminum gallium garnet (YAGG:Ce3+) nanophosphors were synthesized using the sol-gel method. Mixed garnet of Y2.97Al5-xGaxO12:Ce0.03 was prepared with varying gallium content: x = 0, 1, 2 and 3 Ga. The effect of gallium substitutions on the structural, photo and thermoluminescence properties of the prepared nanophosphors were studied by X-ray diffraction (XRD), photoluminescence (PL) and thermoluminescence (TL) techniques. XRD results indicated that the single and pure cubic crystal phase was formed for all nanophosphor samples regardless of the Ga content. The PL spectra of all the samples exhibited a green-yellow emission band centered at 522 nm attributed to the 5d → 4f transitions of Ce3+ ions. The TL glow curve spectra recorded after β-particle irradiation showed a strong dependence in terms of position, shape and intensity, of all temperature peaks with the Ga content. The highest TL sensitivity was observed for the sample prepared with x = 2 Ga, with main peak arising at low temperature (85 °C). The sample prepared at x = 1 Ga exhibited also high TL sensitivity with a simple glow curve spectrum showing a main peak at high temperature (∼158 °C). Thus, the linear dose response of this sample has been investigated in the wide dose range from 0.125 to 100 Gy in order to evaluate the potentiality of this material for radiation dosimetry applications.

Xenon Nanobubbles and Residual Defects in Annealed Xe‐Implanted Si(001): Analysis by the Combination of Advanced Synchrotron X‐Ray Diffraction and Transmission Electron Microscopy Techniques

AbstractResidual crystalline defects on the subsurface of Xe‐implanted Si(001) and post‐annealed substrates are investigated by advanced X‐ray diffraction and transmission electron microscopy techniques. Local characterization highlights the features of recrystallization and structural evolution induced by thermal treatments resulting from the formation of gaseous Xe nanobubbles embedded in a heavily twinned surrounding Si matrix. Both mappings of conventional reciprocal space and X‐ray multiple‐beam diffraction exhibited different aspects from the kinematical and dynamical X‐ray theories, respectively, contributing to a better understanding and description approach of residual damage in ion‐beam implanted materials. A simple layered model is proposed based on the experimental Q‐Scans profiles and computational calculations, distinguishing host matrix structural strain artifacts from the Xe‐bubbles pressure probed by a Xe M4,5‐edge blue shift in EELS spectra. Bubble pressure is determined by extrapolating the equation of state for xenon at high temperatures. The study also supports an experimental constant CXeM‐edge for the ∆E ≅ C n theoretical expression.

High pressure neutron diffraction study of magnetic ordering in erbium

We have studied magnetic ordering in polycrystalline erbium at high pressures up to 32 GPa and low temperatures down to 10 K using neutron diffraction techniques at the Spallation Neutron Source at Oak Ridge National Laboratory, USA. For the hexagonal close-packed (hcp) phase, strong nuclear and magnetic satellite intensities permit a simultaneous refinement of the nuclear and magnetic structures. At 1 GPa of applied pressure, a modulation vector q=γc∗ with γ≈2/7 for the c-axis modulated and cycloidal phases is consistent with prior single-crystal studies at low pressures. At 6.7 GPa in the hcp phase, we find γ≈0.31, indicating a reduction in the period of the magnetic structure with respect to the crystal lattice. The magnetic ordering temperature at 6.7GPa is slightly above 60 K. At 32 GPa in the double hexagonal close-packed phase, the magnetic scattering constrains the magnetic ordering temperature to 25±5 K. Our neutron diffraction study demonstrates that the magnetic ordering persists in the high-pressure double hexagonal close-packed phase of erbiumto the highest pressure of 32 GPa.

Change in Hydrogen Trapping Characteristics and Influence on Hydrogen Embrittlement Sensitivity in a Medium-Carbon, High-Strength Steel: The Effects of Heat Treatments.

Medium-carbon, high-strength steels are widely used in the field of hydrogen energy because of their good mechanical properties, and they can be readily tailored by heat treatment processes such as the normalizing-tempering (N&T) and quenching-tempering (Q&T) methods. The hydrogen embrittlement (HE) susceptibility of a medium-carbon, high-strength steel was investigated utilizing microstructural characterization with scanning electron microscopy (SEM), the electron backscatter diffraction (EBSD) technique, and transmission electron microscopy (TEM). A study was also conducted on the steel's hydrogen transport behavior as affected by the N&T and Q&T treatments. The steel contained more hydrogen traps, such as dislocations, grain boundaries, lath boundaries, and carbide interfaces, after the Q&T process, which was associated with a lower HE sensitivity when comparing the two treatments. In comparison, the N&T process produced larger-size and lesser-density carbides distributed along the grain boundaries, and this resulted in a relatively higher HE susceptibility, as revealed by the slow-strain-rate tensile (SSRT) tests of the hydrogen-charged steels and by the fractographic study of the fracture surface.

Microstructure, mechanical properties and corrrosion behavior of Al-Zn-Mg-Cu wire under different annealing conditions

Al-Zn-Mg-Cu aluminum alloy wires were annealed at 404 °C and then cooled at 10–100 °C/h. On the basis of the cooling speed of 10 °C/h, a second stage of 232 °C annealing was added and held for 4–8 h. The differences in grain organization, grain boundary precipitation phase, electrical conductivity, mechanical properties and intergranular corrosion properties of Al-Zn-Mg-Cu aluminum alloy wires with different annealing processes were comparatively investigated by using electron backscatter diffraction (EBSD) technique, transmission electron microscope (TEM), electronic tensile tester, conductivity meter. It is found that the grain size of Al-Zn-Mg-Cu wire after different annealing processes has not grown significantly, and the grain orientation has not changed obviously. As the cooling speed decreased from 100 °C/h to 10 °C/h, the precipitated η phase continued to merge and grow, from chain distribution to independent distribution, and the Cu element in η phase increase. The Cu content of η phase increases to 14.7 wt% by adding a second annealing stage. The conductivity of the alloy increases to 48.6 %IACS and the tensile strength is reduced to 168 MPa. In addition, the maximum corrosion depth of the alloy is reduced to 16 μm. It shows good mechanical properties and excellent corrosion resistance.

The Role of Microstructure in the Gradient of Tensile Properties through Thickness in 7449 Aluminium Alloy Thick Plate

AbstractIn this article, the yield strength, tensile strength, and the microstructure of the wrought aluminium alloy 7449 rolled thick plate have been studied through thickness under different temper conditions. For all heat treatments, it has been proven that the yield strength and tensile strength values increase from the surface to the centre. The largest difference between the centre and the surface, in both properties, occurs in the case of a sample aged at room temperature for 120 h (TTA temper). The sample artificially aged at 120 °C for 24 h (TTB temper) shows the best strength-gradient relationship of the tensile properties through the thickness. Metallographic characterisation carried out by optical and scanning electron microscopy shows much finer elongated grains in the region near the surface of the plate than in the centre, with incipient recrystallisation in the area near the surface. In addition, electron backscattered diffraction technique, used for micro-texture analysis, has proven the presence of a gradient of crystallography texture in the plate. This explains the yield strength gradient, since the rate of change of the Taylor factor through thickness correlates with the rate of the change of yield strength in the longitudinal direction for the samples studied.

Provenance of the Bronze Age lapis lazuli pieces from the Early Urban Center of Konar Sandal, Jiroft, Southern Iran

The sources of lapis lazuli objects found in the Bronze Age of the Iranian Plateau and its trade routes have been a subject of interest and a research question. Four archaeological pieces of lapis lazuli recovered from a stone-working workshop in the Bronze Age site of Konar Sandal South (Jiroft Plain), southern Iran, were analyzed using X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) techniques to characterize the mineralogical composition and the possible provenance of raw materials. Results showed that these objects are identical based on their composition, presenting diopside and specific trace element proportions as provenance markers. Comparison with available data from Iranian archaeological sites and ancient resources from Central Asia revealed that these finds may have been imported from lapis lazuli mines located at Badakhshan in Afghanistan, as they were supplied raw materials for ancient lapis lazuli objects of Iran.

New frontiers in thermal energy storage: An experimental analysis of thermophysical properties and thermal stability of a novel ternary chloride molten salt

It has been always a daunting task to develop thermal systems with a wide range of thermochemical properties and high stability. It presents a significant challenge, especially when aiming to utilize them for heat storage and transfer applications. In this regard, the thermal characteristics and thermal stability behaviour of molten salt mixture as a heat transfer fluid (HTF) at high temperatures were explored. A novel ternary eutectic salt mixture (base mixture) made of cuprous chloride (CuCl), potassium chloride (KCl) and sodium chloride (NaCl) was investigated as HTF for thermal energy storage (TES) system with a range up to 653 °C in a concentrated solar power (CSP) plant. To extend the temperature span and stability, the effect of an additive was investigated. Different compositions were studied in detail concerning the properties and stability regarding the additive. The molten salt with 7 % CaCl2 additive improved thermal stability and operating temperature from 653 °C to 700 °C. The transport characteristics and thermal stability of the eutectic mixture with and without the additive were measured by high-temperature thermal analyzers. The results indicated that the melting temperature decreased and the average specific heat capacity considerably increased with the addition of CaCl2 additive compared to the ternary chloride base mixture. As the temperature increased, the eutectic salt mixture exhibited a reduction in viscosity and density. The viscosity and density of the salt mixture with and without the additive were almost uniform at 700 °C. The average thermal conductivity of the ternary salt mixture with and without additives was 0.72 W/(m°C) which is much more than that of Solar and Hitec salts. In a 100 h experiment of long-period isothermal stability, the eutectic salt mixture showed less than 4 % weight loss at 700 °C. It was defined as the highest operating temperature at which the eutectic salt mixture remained stable. The stability and recyclability of the salt mixture were confirmed through the short-period stability test. The effect of the CaCl2 additive on thermal stability of base salt mixture was analyzed by X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) techniques. According to the results, this novel eutectic salt mixture had outstanding thermal stability up to 700 °C and could be employed as a viable TES material in CSP plants.

Design of Silk Fabric Surface with Enhanced Antiseptic Properties through Graft Modification and Iodophor Integration

AbstractTo improve the hydrophobic character of silk and impart iodine complex ion adsorption, the surface of woven silk fabric is enriched by different functional groups through the grafting of N‐vinylpyrrolidone (NVP), ethylene glycol dimethacrylate (EGDMA), and their mixtures (NVP–EGDMA). The dominant fibrous texture of silk enables an efficient graft copolymerization in terms of high grafting yield (>30%) after applying a mild degumming process. The structural and morphological alterations in the silk surface are evidenced with attenuated total reflectance‐fourier transform infrared spectroscopy (ATR‐FTIR), X‐ray diffraction (XRD), and scanning electron microscopy (SEM) techniques. The imparted hydrophilicity property of the samples is revealed by contact angle–wetting time measurements. The usability of the graft‐modified samples as an iodophor polymeric substrate is then examined by treatment with I2/KI solutions, and the results are monitored using UV–vis spectroscopy. It is obtained that the NVP–EGDMA mixture‐grafted sample exhibits satisfactorily high iodine adsorption compared to untreated and NVP‐grafted silk samples, such as 0.05 g per 1 g fabric with high antibacterial activity against various pathogens, including methicillin‐resistant Staphylococcus aureus (MRSA) responsible for hospital‐acquired infections. This finding evidences its potential as an alternative antiseptic tissue for biomedical applications.

Effect of titanium interlayer configurations on residual stresses and performance of titanium/titanium nitride multilayer coatings

Multilayer coatings provide an effective measure to control and optimise of residual stresses, enhance coating adhesion, fracture toughness, wear and corrosion resistance of coating system. In this study, we designed and produced bi-layer and four-layer titanium/titanium nitride magnetron sputtered coating configurations by altering the position of the interlayer. The in-plane residual stresses in different coating configurations are measured by multiple peak grazing incidence X-ray diffraction techniques. Subsequently, the effect of different compressive residual stresses on adhesion, mechanical properties, wear and corrosion resistance of coatings are investigated. Results show that the position of interlayer in multilayer coating configuration has a great impact on relaxation of residual stresses. The residual stresses are relieved by 26% and 46% by lowering the position of titanium interlayer from 800 nm at the top to 1000 nm and 1200 nm, respectively. The nanoindentation hardness is decreased by 11% and 13%, respectively. The wear rate of multilayer coating having interlayer position at 800 and 1000 nm from the top is ≈ 23% lower compared to bilayer however it is increased by ≈ 50% when interlayer coatings position changed to 1200 nm from the top. The interposition of interlayer in multilayer coating configurations decreased the corrosion current density by ≈ 50%. All multilayer coatings including higher residual stresses show better adhesion to the substrate compared to bilayer coatings which shows severe delamination.

Flow behavior and dynamic recrystallization mechanism of a new near-alpha titanium alloy Ti-0.3Mo-0.8Ni-2Al-1.5Zr

A new near-α titanium alloy Ti-0.3Mo-0.8Ni-2Al-1.5Zr was designed based on Ti-0.3Mo-0.8Ni (TA10). The hot compression tests were carried out at temperatures of 800–970 °C and strain rates of 0.01–5 s−1. The results show that the flow softening phenomenon in the α + β phase region is more distinct than that in the single β phase region. The Arrhenius constitutive models based on strain compensation in the α+β phase region and β phase region were established respectively, and the correlation coefficient between the predicted flow peak stress values and the experimental values reached 0.99365. The hot processing map of the alloy was established, the processing parameters of the peak efficiency: 800 ≤ T ≤ 818 °C, 0.01 ≤ ε˙ ≤ 0.0235 s−1, and 960 ≤ T ≤ 970 °C, 0.01 ≤ ε˙ ≤ 0.0213 s−1. The microstructure evolution and deformation mechanism of the compressed specimens were researched by electron backscatter diffraction (EBSD) technique. There were two nucleation mechanisms for dynamic recrystallization (DRX): sub-grains growth nucleation and high angle grain boundaries (HAGBs) bulging nucleation, the former was continuous dynamic recrystallization (CDRX), and the latter was discontinuous dynamic recrystallization (DDRX). The flow stress in the α+β phase region was softened by CDRX and dynamic recovery (DRV), while the principal deformation mechanisms in the β phase region are DRV and DDRX. The dislocation strain energy and recrystallization ability at different temperatures were quantitatively analyzed by the kernel average misorientation (KAM) and the geometrically necessary dislocation (GND), and the results showed that more complete recrystallization occurred at lower temperature in the α + β phase region. The HCP slip was principally completed by prismatic ⟨a⟩ and pyramidal ⟨c+a⟩ slip systems during the hot compression, while BCC was a mixed mode of {110}, {112} and {113} multiple slips.

Syntheses, Crystal Structure and Theoretical Properties of Schiff Bases Obtained from Isoniazid and Pyridine‐2‐, 3‐, 4‐Carboxaldehyde and Their Zinc(II) Complexes

AbstractThe series of Schiff base ligands, N’‐(pyridine‐2‐ylmethylene)isonicotinohydrazide (I), N’‐(pyridine‐3‐ylmethylene)isonicotinohydrazide (II) and N’‐(pyridine‐4‐ylmethylene)isonicotinohydrazide (III), and the Zn(II) complexes of the ligands (I and II), [N’‐(pyridine‐2‐ylmethylene)isonicotinohydrazide]‐trichlorozincoate (IV) and [N’‐(Pyridin‐3‐ylmethylene) isonicotinohydrazide] trichlorozincoate (V) have been newly synthesized and their structures have been characterized by 1H, 13C NMR and FT‐IR spectroscopies, elemental analysis and single crystal X‐ray diffraction technique. The Hirshfeld surface analyses have been confirmed the importance of H‐atom contacts in establishing the packings. The ground state equilibrium geometries of the synthesized compounds are optimized at DFT/B3LYP/6‐311++G (d, p) and HF/6‐311++G (d, p) levels of theory (for the ligands) and B3LYP/GENECP method is used as the mixed basis sets of LANL2DZ (for Zn) and 6–311G (for other atoms) in the gas‐phase. The structural parameters obtained from the theoretical studies of the compounds are compared with their experimental ones. Their linear and nonlinear optical (NLO) properties are also calculated by the same methods. In the ground state, the energy band gaps (Eg) of the Schiff bases (I, II and III) have been calculated as 4.38 eV, 4.36 eV and 4.46 eV (at B3LYP) and 9.94 eV, 9.81 eV and 10.20 eV (at HF), respectively.

Green synthesis of silver nanoparticles using mature-pseudostem extracts of Alpinia nigra and their bioactivities

Abstract Green synthesis of silver nanoparticles (AgNPs) employing agricultural wastes as plant extracts to improve environmental benignity and also economic value added is the highlight of this research. The mature pseudostem of Alpinia nigra is an unbeneficial raw material discarded from several food ingredients and medicinal formulas. Therefore, this research focused on condition optimization for AgNP synthesis with ecofriendly techniques using A. nigra mature-pseudostem extracts and evaluation of their antioxidant, antibacterial activities, and toxicity with brine shrimp lethality assay (BSLA). The optimal reaction conditions were achieved by using 5 mM silver nitrate (AgNO3) solution with a volume ratio of 2:8 for the extract to AgNO3 at pH 12 under room temperature. The morphology and crystalline phase of the generated AgNPs were characterized using UV–visible spectrophotometry, field emission-scanning electron microscope (FE-SEM), energy dispersive X-ray, X-ray diffraction, and Fourier transform-infrared (FTIR) techniques. The FE-SEM analysis exposed spherical shapes with an average diameter of approximately 49 nm. The XRD analysis indicated their face center cubic structure, and the FTIR spectra confirmed that phytochemicals from A. nigra extract promoted the synthesis of AgNPs. In particular, the biosynthesized AgNPs presented potential antibacterial activity against both Staphylococcus aureus and Escherichia coli and effective antioxidant capacity using the DPPH radical scavenging assay. Additionally, non-toxic desired AgNPs were confirmed with BSLA.

Tailoring the Microstructure using Quenching and Partitioning Processing in a Commercial Mn-Si-Cr Spring Steel to Improve Tensile Properties

AbstractThis study explores a novel approach to quenching and partitioning (Q&P) heat treatment applied to AISI 9260 spring steel, comprising Fe-0.65C-1.58Mn-1.05Si-0.41Cr (wt.%). Our research focuses on balancing strength and ductility through optimized Q&P pathways, leading to a diverse microstructure that includes martensite, bainite, carbide, and retained austenite. Advanced X-ray diffraction and scanning electron microscopy techniques were employed to analyze the complexities of this microstructure. A key aspect of this study is the precise control of partitioning temperature and time, crucial for modulating lattice distortion and dislocation density within martensitic and bainitic structures. Optimal partitioning temperature promotes carbon distribution into austenite, tempering lattice distortions, and dislocation densities. Concurrently, carbide precipitation and segregation contribute to the refinement of the bainite phase. The sample quenched at 125 °C and partitioned at 350 °C (Q&P-125/350) demonstrates notable mechanical properties: a yield strength of 950 ± 15 MPa, an ultimate tensile strength of 1710 ± 15 MPa, and an elongation of approximately 9.7%. These results are partly attributed to the effect of silicon in preventing cementite coarsening and the effective distribution of carbide. Our findings highlight the potential of Q&P heat treatment in developing tailored microstructures with enhanced mechanical properties in steel, without relying on costly alloying elements. This approach presents new avenues for the design and application of high-performance materials.

Exploring a path of vegetation restoration best suited for a photovoltaic plant in the Hobq desert

To investigate the soil improvement effects of different vegetation restoration measures during the operation and maintenance of photovoltaic power plants in the Hobq Desert. This study determined the soil grain size composition and soil nutrient content of 0–5 cm under four vegetation restoration measures and within the mechanical sand barriers by laser diffraction techniques and chemical experiments. The results showed that: (1) Soil particle size composition in the study area is predominantly sandy, with 1.02%, 6.63%, 5.34% and 2.61% less sand in Leymus chinensis (YC), Glycyrrhiza uralensis (GC), Artemisia ordosica Krasch (YH) and Hedysarum scoparium (HB), respectively, compared to mechanical sand barriers (CK). Soil particle distributions of YC, GC, and HB showed better sorting and more concentrated patterns, and all four vegetation restoration measures had higher fractal dimensions than CK. (2) AN (Alkali-hydrolyzable Nitrogen) content performance: The content of YC, GC, and HB was significantly higher than that of YH and CK, AP (Available Phosphorus) content did not differ significantly between measures, AK (Available Potassium) content was higher than that of CK in all measures, with YC content being the highest and SOM content being the highest for GC. (3) Soil total nutrient is unstable across vegetation restoration measures. Overall, the performance showed that the three vegetation restoration measures, YC, GC, and HB, were more evident in the soil total nutrient content improvement. Each particle size characteristic parameter and soil nutrient response vegetation restoration measures ameliorate sandy soil in PV power plants during operation and maintenance. YC and GC have the most apparent effect on soil amelioration.