Peak Profile Analysis Research Articles

Determination of Structural Elements of Hydrothermally Synthesized CeO₂ Nanoparticles by Monshi, Williamson–Hall, Halder–Wagner, and Size–Strain Plot Methods, and Effect of Annealing Temperature

AbstractCeO₂ nanoparticles are synthesized hydrothermally using CTAB as a surfactant, cerium nitrate hexahydrate (Ce(NO3)3·6H₂O) as a precursor and urea. The synthesized CeO₂ nanoparticles are characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction peak profile analysis (XRD), Scanning electron microscopy (SEM), and UV–vis. The X‐ray diffraction results revealed that the sample is crystalline with a face centered cubic (fcc) phase having cubic fluorite structure. The structural elements of prepared samples have been investigated by various methods. The Monshi, W–H analysis, size–strain plot, and H–W methods are used to study crystallite sizes and lattice strain on the peak broadening of CeO₂ nanoparticles. Further, the lattice constant of the cubic fluorite has also been estimated from the Nelson–Riley plot. The parameters, including strain, stress, and energy density value, are calculated for all the reflection peaks of X‐ray diffraction corresponding to cubic fluorite phase of CeO₂ lying in the range 20°–80° and at different temperatures.

Moment analysis method for the determination of permeation kinetics of coumarin at lipid bilayers of liposomes by using capillary electrophoresis.

A method was developed for studying mass transfer kinetics at lipid bilayers of liposomes. Elution peaks of coumarin were measured by liposome electrokinetic chromatography (LEKC). Four types of phospholipids having different alkyl chains were used for preparing liposomes, which were used as pseudo-stationary phases in LEKC systems. Rate constants of permeation across lipid bilayers of liposomes or of adsorption at lipid membranes were determined by analyzing the first absolute and second central moments of the elution peaks measured by LEKC. The rate constants of permeation or adsorption tend to decrease with an increase in the carbon number of the alkyl chains of phospholipids. It was demonstrated that the moment analysis of elution peak profiles measured by LEKC is effective for determining lipid membrane permeability or adsorption kinetics. Compared with other conventional techniques, the method has some advantages for studying mass transfer kinetics at lipid bilayers. Solute permeation across or solute adsorption at real lipid bilayers of liposomes is analyzed. The principle of the method is the analysis of separation behavior in LEKC, which is different from that of the other ones. It is expected that the method contributes to the kinetic study of mass transfer at lipid bilayers from various perspectives.

The role of the cation and anion in aqueous liquid chromatography with sodium dodecyl sulphate and imidazolium-based ionic liquids as mobile phase reagents

BackgroundIn reversed-phase liquid chromatography, solute retention is primarily influenced by interactions between a nonpolar stationary phase and a moderately polar hydro-organic mobile phase, based on the solute lipophilicity. However, challenges regarding retention and peak tailing can arise due to ionic interactions between positively charged analytes and free silanols present on silica-based stationary phases. To address these challenges, incorporating surfactants and ionic liquids (ILs) into the mobile phase offers an effective solution. These additives synergistically enhance chromatographic performance through electrostatic and lipophilic interactions, which enable fine-tuning of selectivity and improved separation efficiency. ResultsThis study explores the chromatographic behaviour of several basic compounds in aqueous mixtures containing the anionic surfactant sodium dodecyl sulphate (SDS), above its critical micellar concentration, combined with various 1-alkyl-3-methylimidazolium-based ionic liquids (ILs) featuring chloride, tetrafluoroborate, and hexafluorophosphate anions, all without the addition of organic solvents. Specifically, this research investigates the influence of different anion types within the ILs and considers the impact of the IL cations. Analysis of solute peak profiles reveals narrow and symmetrical peaks. By introducing tetrafluoroborate and hexafluorophosphate IL anions into a mobile phase that contains an anionic surfactant, the study sheds light on the interactions occurring within the chromatographic column. This enhanced understanding of the combined effects of surfactants and ILs contributes to refining chromatographic methodologies. SignificanceThis research highlights the importance of carefully selecting the appropriate IL when incorporating it into a micellar mobile phase alongside SDS. This combination results in practical retention times that surpass the performance achieved with either the surfactant or IL alone in the mobile phase. The study particularly emphasises the impact of the IL anion, especially in the absence of SDS and organic solvents. This unveils interactions that are otherwise obscured in micellar and hydro-organic media, providing new insights into chromatographic dynamics.

Confirmation of the presence of edge dislocations in the prepared FCC ZnTe nanocrystals from the study of structural analysis through the MWH method with added Fourier analysis (W-A method) of diffraction peaks

Nanocrystalline ZnTe with cubic mono-phase has been synthesized by a wet-chemical synthesis process for the study of the presence of dislocations through X-ray diffraction peak profile analysis. The average size of the ZnTe nanocrystals has been determined from the High-Resolution Transmission Electron Microscopic (HRTEM) analysis as 21.9 nm. In the XRD pattern, (111), (200), (220), (311), and (400) diffraction planes have been observed, which confirms the formation of cubic mono-phase of ZnTe. For the extraction of microstructural details, the Rietveld refinement has been performed using Fullprof software and from this refinement, the lattice constant has been obtained as 6.17 Å under the space group of f-43. Here, X-ray diffraction peak has been analyzed through the Williamson-Hall (W–H) analysis method and the Warren-Averbach (W-A) analysis method. Williamson-Hall approach is based on the full-width at half-maxima analysis, whereas the Warren-Averbach method is related to the analysis of the Fourier transform of the broadened X-ray diffraction peaks. For considering and analyzing the anisotropic broadening of the peak, modified Williamson-Hall and modified Warren-Averbach methods have been used for the calculation of size, strain, and dislocation density. The presence of prominent edge dislocation of about 71 % has been confirmed from the anisotropic peak broadening study. In addition, the HRTEM image directly verifies the presence of edge dislocations in both the lattice planes of (111) and (220).

Electret‐induced antibacterial response of Mg1‐xCaxSi1‐xZrxO3 (x = 0–0.4) bioceramics

AbstractThe potential risk of bacteria‐induced prosthetic infection during implantation/post‐operative healing raises a serious concern about the success of implant/surgery. In this context, the present study successfully established the antibacterial efficacy of the electret form of Mg1‐xCaxSi1‐xZrxO3 (x = 0, 0.1, 0.2, 0.3, 0.4 [MCSZO‐X]) bioceramics, toward both, Escherichia Coli and Staphylococcus aureus bacteria with reference to those of hydroxyapatite (HAP). MCSZO‐X bioceramics were synthesized using a solid‐state route. The influence of Ca‐ and Zr co‐doping on the crystallite size of MCSZO‐X has been analyzed using X‐ray peak profile analyses. The electrets were developed by corona poling of sintered MCSZO‐X samples at voltage and temperature of 20 kV and 500°C (30 min), respectively. The charge, stored on the surface of MCSZO‐X electret samples was calculated to be 0.253, 0.294, 0.320, 0.173, and 0.161 µC/cm2 via thermally stimulated depolarized current measurement. The positive and negative ends of MCSZO‐ X electrets exhibited a reduction in the viability of E. coli bacteria by (24%, 25%, 30%, 43%, and 42%) and (29%, 37%, 39%, 51%, and 48%), respectively, in comparison to those of HAP. On the contrary, the viability of S. aureus bacteria has decreased by (26%, 33%, 35%, 46%, and 42%) and (21%, 22%, 27%, 395, and 37%) on the surfaces of the positive and negative ends of MCSZO‐ X electrets, respectively, with the reference of those of HAP. The mechanism of electret‐induced antibacterial activity has been revealed via various assays, such as catalase activity, superoxide production (SOD), , protein estimation, and lipid peroxidation (LPO) assays. The positive ends of MCSZO‐X electrets demonstrate antibacterial efficacy by means of more reactive oxygen species generation as compared to their negative ends of electrets and uncharged surfaces of MCSZO‐X samples, as revealed by SOD, protein estimation, catalase activity, and LPO assays. However, the negative ends of electrets prevent the adhesion of bacterial cells via electrostatic repulsion.

Exploration of properties (crystallographic, morphological, optical) of nano cobalt aluminate synthesized by facile sol–gel method: Effects of sintering temperature

The present work reports on the facile sol–gel synthesis of CoAl2O4 nanoparticles using cobalt nitrate and aluminum nitrate as the metal salts and citric acid and glycerol as chelating agents. The consequence of sintering temperature on the structure, particle size, morphology, composition, zeta potential, color, and reflectance spectra at neutral pH condition were explored with various instrumental techniques. The CoAl2O4 nanoparticles were characterized with Powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FESEM), Energy dispersive spectroscopy (EDS), Nanoparticle size analyzer, Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV–Vis-DRS) and CIE-Lab colorimetric method. From the data of PXRD, the crystallite size and peak profile analysis were investigated by four different models. It was found that the average crystallite size varied in the range of 28.01–320.97 nm and single-phase cubic CoAl2O4 was formed without any impurity. The average particle size of CoAl2O4 nanoparticles was discerned from the FESEM images using ImageJ software and from a nanoparticle size analyzer. The average particle sizes were increased with the increasing sintering temperature. The values of zeta potential found in all of the samples represented high dispersion stability. From the colorimetry of CoAl2O4 nanoparticles, the CIE-La*b* output illustrated high purity and brightness and the spectra.

Green synthesis of Ag2O & facile synthesis of ZnO and characterization using FTIR, bandgap energy & XRD (Scherrer equation, Williamson-Hall, size-train plot, Monshi- Scherrer model)

A typical study has been performed for synthesizing Ag2O and ZnO nanoparticles. In our case, aloe vera extract was used as a reducing agent for synthesizing Ag2O. This green synthesis of silver oxide used silver nitrate (AgNO3) as a precursor material. On the other hand, the direct precipitation method was used for synthesizing zinc oxide nanoparticles, in which the precursor materials used were zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and potassium hydroxide (KOH). Afterward, the characterization of these synthesized nanoparticles was done by the X-ray diffraction (XRD) method. Then, the crystal size, lattice strain, stress, and energy density of synthesized ZnO and Ag2O were determined by using XRD peak profile analysis. Among the various available models for determining these microstructural parameters, we explored the Scherrer model, the linear straight-line method of the Scherrer equation, the Monshi-Scherrer model, the Sahadat-Scherrer model, the Williamson-Hall model (including the uniform deformation model, the uniform stress deformation model, the uniform deformation energy density model), the size-strain plot method, the Halder-Wagner model, etc. By employing the crystal size values from these models, the accuracy and validity of crystals were also performed. The synthesized products were also characterized by the exploration of functional groups (by FTIR) and optical band gaps (by UV technique).

Retracted: XRD Peak Profile Analysis of SiC Reinforced Al2O3 Ceramic Composite Synthesized by Electrical Resistance Heating and Microwave Sintering: A Comparison

Retracted: XRD Peak Profile Analysis of SiC Reinforced Al₂O₃ Ceramic Composite Synthesized by Electrical Resistance Heating and Microwave Sintering: A Comparison

Influence of Metal (Al, Mg, Sm, and Cu) Dopants on Structural, Optical, Magnetic, and Antimicrobial Properties of ZnO Nanopowders Synthesized by Coprecipitation Method

Pure and metal‐doped ZnO nanopowders with composition formula M0.04Zn0.96O (where M = Al, Mg, Sm, and Cu) are synthesized using the coprecipitation method. The structural characterization of synthesized powders is investigated using X‐ray diffraction and the results confirm the hexagonal wurtzite structure without any additional phases. The change in structural parameters of ZnO with dopants is estimated using X‐ray peak profile analysis. The structural characterization is further analyzed by Fourier‐transform infrared spectroscopy. The size and morphology of the synthesized powders are analyzed by a field‐emission scanning electron microscope, which also evidences the formation of uniform nanostructures with quasi‐spherical and hexagonal shapes. Moreover, the elemental composition of these metal‐doped nanotructures is determined by energy‐dispersive X‐ray measurements. UV–vis spectroscopy is used to determine the energy bandgap of ZnO nanopowders. A vibration sample magnetometer is employed to measure the samples' magnetic properties, and dopants are found to induce distinct magnetic behaviors in ZnO. The antimicrobial activity of the synthesized powders is measured using the well diffusion method. It is observed that the introduction of dopant metals leads to increased microbial activity. Among the doped ZnO variants, Al‐doped ZnO exhibits the highest level of microbial activity compared to pure ZnO and other samples.

Impacts of annealing temperature on microstructure, optical and electromagnetic properties of zinc ferrites nanoparticles synthesized by polymer assisted sol-gel method

Nanocrystalline zinc ferrite (NZF) were successfully synthesized at different calcination temperature via sol-gel method from the precursor salt solutions using tartaric acid and PVA solution as a chelating agent and binder respectively. The characterization of NZF and their properties had been investigated using sophisticated techniques viz. X-ray diffraction, Fourier transform infra-red spectroscopy, Scanning electron microscopy, Transmission electron microscopy, Energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, UV–Vis-NIR spectroscopy, Vibrating sample magnetometer and Impedance analyzer. X-ray peak profile analysis through Debye Scherer and Wilson method, Halder-Wagner method has been used to estimate the structural parameters. The crystallite size and particle size of ZnFe2O4 samples were found to increases with increasing annealing temperature while lattice parameters and lattice strain decreases. Dynamic light scattering and zeta potential measurements were used to evaluate the particle size distribution and stability of these systems. The room temperature magnetic properties measurement showed that the net magnetic moment is observed for NZF due to cation distribution although the bulk ZnFe2O4 is non-magnetic. Direct optical band gaps of the prepared NZF samples has been investigated by UV–Vis NIR spectroscopy using Tauc formula and found that energy band gaps (Eg) values are in a narrow range of 1.19–1.86 eV. The frequency dependent dielectric properties, impedance and modulus spectroscopy measurement has been investigated in the frequency range of 100 Hz to 20 MHz. The synthesized NZF particles will be applied for Gas sensor, humidity sensor and photocatalyst.

In English

Hybrid carbons/metals/metal (metalloid) oxides composites could be effective adsorbents for low– and high–molecular weight compounds, polar and nonpolar, gaseous and liquid. The presence of metal nanocrystallites and carbon nanostructures could provide catalytic properties in redox reactions. For more effective use of hybrid composites, their morphological, structural, textural, and adsorption characteristics should be appropriate for target applications and, therefore, well controlled. Therefore, the aim of this study was to synthesize carbon/metal/silica nanostructured composites with varied content of metal (Ni) to control the mentioned characteristics. Precipitated silica Sipernat 50 was selected as a substrate. Potato starch was used as a carbon precursor. Nickel nitrate (Ni(NO3)2·6H2O) of varied amounts was used as a precursor of Ni nanoparticles reduced upon the starch carbonization. After the starch carbonization and Ni reduction, a set of C/Ni/silica samples was studied using atomic force microscopy, X–ray diffraction, X–ray fluorescence spectroscopy, nitrogen and p-nitrophenol adsorption, thermogravimetry, and Raman spectroscopy. The presence of nickel phase results in the formation of smaller but denser packed char nanoparticles. Estimation of possible contribution of pores accessible for nitrogen molecules in silica globules and outer surface of carbon/Ni particles suggests that the carbon phase is porous that provides a significant part of the specific surface area of the composites. Amorphous silica and char phases are characterized by the presence of certain nuclei of radius (R) < 1 nm and 2 nm < R < 10 nm estimated from the XRD patterns using full peak profile analysis with a self–consistent regularization procedure. Ni crystallites are of several sizes, since particle size distributions include two–three peaks in the range of 3–13 nm in radius. The Raman spectra show that the main changes with increasing Ni content are characteristic to sp3 carbon structures (D line) in contrast to the sp2 structures (G line). The pore size distributions (both differential and incremental) demonstrate complex changes in a broad size range due to increasing Ni content in composites. As a whole, changes in the Ni content in nanostructured C/Ni/silica composites allow one to control the morphological, structural, and textural characteristics of the whole materials.

High temperature sliding wear behavior of detonation sprayed Ni-5wt%Al coating

The tribological behavior of detonation (DSC) sprayed Ni-5%wtAl coatings at room temperature (25 °C) and elevated temperature (850 °C) has been studied in this work. Dry sliding wear experiments were done by using alumina (Al2O3) ball-on-disc tribometer. FESEM-EDS and a non-contact 3D profilometer microanalysis were used to evaluate the worn scar and wear rate and identify the wear mechanism. X-ray diffraction (XRD) investigation indicated that the Ni-5wt%Al coating predominantly consists of γ-Ni phases at 25 °C and 850 °C conditions. The phase evolution, thermal expansion, crystallite size, and lattice strain were evaluated using in-situ high-temperature X-ray diffraction (HT-XRD). The crystallite size (D) and lattice strain (ε) were determined by Williamson-Hall analysis using a uniform deformation model (UDM), employing X-ray peak profile analysis (XPPA). In high-temperature conditions, the thermal expansion mismatch between the coating and substrate is negligible, with reduced spallation and cracking at the interface. The findings of the wear tests revealed that as the temperature increased, the coefficient of friction (CoF) and wear rate (ω) significantly decreased as the wear mechanism changed from abrasive to adhesive. The improvement of wear resistance of Ni-5wt%Al coating at high temperatures has been evaluated and discussed from the perspective of thermal expansion and tribo-layer formation.

Estimation of lattice strain and structural study of BaTiO3/PS polymer composite using X-ray peak profile analysis

Estimation of lattice strain and structural study of BaTiO3/PS polymer composite using X-ray peak profile analysis

Effect of metal ions on structural, morphological and optical properties of nano-crystallite spinel cobalt-aluminate (CoAl2O4)

The bright blue nano crystallite cobalt aluminate (CoAl2O4) was synthesized by sol–gel method using a mixture of chelating agent of glycerol and citric acid. The effects of changing (0.05, 0.075, 0.10, 0.25, 0.50, and 0.75 mol/L) metal ion concentration on the structural, morphological and color properties of synthesized CoAl2O4 were characterized by using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), Nanoparticle size analyzer, Simultaneous Thermal Analyzer (STA), UV–vis absorption spectroscopy, and CIE-LAB colorimetric analysis. From the X-ray peak profile analysis, the crystallite size was measured by Debye-Scherrer (D-S) equation, and three different models presenting average crystallite sizes between 88.3 and 125.4 nm.The average lattice strain, dislocation density, lattice constant, cell volume, and zeta potential were between 0.00021 and 0.0058, (1.73 to 12.8) × 1014 (lines/m2), 8.10658 to 8.11181 Å, 533.60 to 533.81 Å3, −56.4 to − 63.5 mV, respectively. Using UV–vis absorption spectroscopy, the band gap was calculated from Kubelka-Munk method, and the values of band gap increasing from 1.82 to 1.84 eV, respectively. The reflectance spectra and the CIE-L*a*b* values of cobalt aluminate is also measured which confirmed the formation of blue nano crystallite cobalt aluminate.

On the possibility of fabricating fully austenitic sub-micron grained AISI 304 stainless steel via equal channel angular pressing

The paper concerns possibility of increasing yield and ultimate stress of austenitic stainless steels by equal channel angular pressing (ECAP). To this end, an AISI 304 stainless steel subjected to eight passes of ECAP in a 105◦ die at 350◦ C. The evolution of microstructure as a function of induced plastic strain (number of passes) was studied in different length scales using light and scanning transmission electron microscope (STEM). An insight into fine details of dislocation structure was possible via X-ray diffraction profile analysis. Changes in the structure of processed samples were correlated with their mechanical properties as determined by tension tests and microhardness measurements. Light microscopy revealed a shear banded microstructure. STEM observations demonstrated co-existence of three types of grain structure: (a) short elongated grains/subgrains of 71 nm average width formed within the shear band regions, (b) a mixture of coarse (200–350 nm in size) and nanocrystalline (15– 70 nm) equiaxed grains developed outside the shear bands, and (c) nano-twin lamellae of 3–20 nm width inside nanocrystalline grains. XRD peak profile analysis using modified Warren–Averbach approach yielded dislocation density as ρ = 4.71 × 1015 m−2 after eight passes. ECAP-induced changes in the microstructure led to a remarkable increase in yield strength of the alloy (YS=1498 MPa, about 3.5 times the initial amount). At the same time, a moderate ductility of εf = 12% was maintained, primarily due to a large post-necking elongation. This behavior was explained by an increase in the strain rate sensitivity of ECAP-ed material in combination with the contribution from transformation induced plasticity, TRIP effect, caused by formation of ∼ 22 vol% martensite during room temperature straining.

Twinning mediated plasticity in high entropy CoCr1.3FeNi0.7MnNbx (x = 0.3, 0.367, 0.4) ultrafine lamellar eutectic by tuning stacking fault energy

We report the twin mediated plasticity in arc-melted high entropy CoCr1.3FeNi0.7MnNbx (0 ≤ x ≤ 0.4) ultrafine lamellar eutectic by tuning stacking fault energy. The phases in eutectic microstructure are identified as FCC phase and HCP-Fe2Nb-type Laves phase with an average lamellae thickness of 323–482 nm. The stacking fault energy of the FCC phase is 11 mJ/m2, as estimated through ab initio calculation and x-ray diffraction peak profile analysis. The concurrent effect of dislocation-slip and twinning deformation in low SFE FCC lamellae along with dislocation-nanotwin interaction have been observed under transmission electron microscopy, which resulted in high strain hardening, high strength of 1.2 GPa, and compressive plasticity of ∼17%. The simultaneous occurrence of multiple deformation mechanism under compression in this novel study provides the basis to design high strength and ductile eutectic high entropy alloy by tuning stacking fault energy.

X-ray diffraction profile analysis of martensitic Ti6Al4V (ELI) parts produced by laser powder bed fusion

The quantification of the density of defects in materials through non-destructive methods is of great interest to scientists and engineers. X-ray diffraction (XRD) peak profile analysis is a valuable method that is often used to reveal important microstructural information, such as defects present in crystalline materials as well as crystallite size. In this study, the broadening of XRD peaks of martensitic Ti6Al4V (ELI) produced by laser powder bed fusion (LPBF) was studied following modified Williamson-Hall (MWH) and Warren-Averbach (WA) analytical methods. The level of defects in martensitic LPBF Ti6Al4V (ELI) was found to drastically reduce by at least 73% after exposing the material to stress-relieving heat treatment.

Crystal structure determination, XRD peak profile analysis and morphological study of double perovskite SrNdFeTiO6

In this work we have proclaimed the synthesis, structural and morphological characterization of the double perovskite oxide SrNdFeTiO6. The material has been synthesized by conventional solid-state reaction technique. X-ray diffraction pattern and Rietveld refinement results have confirmed that the prepared structure crystallizes in orthorhombic phase. The positions of various elements present in the prepared sample have been corroborated by 2D and 3D electron density maps. Peak profile analysis of this double perovskite was carried out by calculating crystallite size using two different methods viz. Debye-Scherrer equation and Williamson-Hall plot method. Both the methods revealed that the crystallite size is in nanometers, however results differ from each other. Microstructural analysis revealed that the synthesized sample has uniform distribution of grains.

Influence of Cu induced crystallographic disorder on the optical and lattice vibrational properties of ZnO nanoparticles.

In this study, the vibrational and optical responses of 0-10% excess Cu incorporated ZnO nanoparticles (NPs) prepared by the low temperature (∼400 °C) wet chemical route were investigated experimentally and were found to be predominantly linked to the formation of both intrinsic and Cu induced crystallographic defects instead of substitutional Cu itself for the first time. For low temperature chemical synthesis, the effective band gap (Eg) of pristine ZnO NPs was found to be as low as 2.84 eV, which was followed by a further reduction by as high as ∼24.4% with gradual Cu inclusion. Excess Cu incorporation was found to drastically restrict the particle growth phenomenon by ∼61% and alter the shape morphology from anisotropic to irregular isotropic. Although all NPs showed a single phase structure with hexagonal P63mc symmetry, the X-ray peak profile analysis along with the characteristic E2(High) Raman peak and electron-phonon coupling strength obtained from the 2nd order Raman mode suggested the presence of appreciable crystallographic disorders pertaining to point defects like Cu induced Zn and O interstitials and vacancies. Optical analysis revealed a gradual increase in Urbach tailing (Eu) from 0.35 to 0.96 eV directly associated with both intrinsic and Cu induced disorders arising from successive Cu incorporation at low processing temperature. A correlation between Eg and Eu predicted a direct-type band-to-band transition energy of ∼3.2 eV for the pristine ZnO crystal, suggesting both intrinsic and excess Cu induced extrinsic disorders to be the primary source of optical modulation of the NPs for the low temperature processing condition.

Stabilised mechanical properties in Ni-based Hastelloy C276 alloy by additive manufacturing under different heat inputs incorporated with active interlayer temperature control

In this study, a Ni-based Hastelloy C276 alloy was prepared using cold metal transfer (CMT)-based directed energy deposition (DED) under different heat inputs with a zig-zag deposition path, integrated with active cooling and interlayer temperature control. Analogous mechanical properties were obtained for the fabricated alloys under different heat inputs (276, 368 and 553 J/mm) through effective interlayer temperature control. Such a broad processing window facilitates the large-scale industrial manufacturing and application of Hastelloy C276 by DED. Nevertheless, the lower heat input appears to slightly refine the microstructure and decrease the mechanical anisotropy of manufactured alloys, which is ascribed to combined effects of the manipulated bulk texture, refined dendrite arm spacing and reduced chemical segregation under lower heat input. Despite the variations of geometrically necessary dislocation (GND) densities with heat inputs, no significant change was observed in the average total dislocation density (TDD) in the microstructure of all samples as suggested by the peak profile analysis of Synchrotron X-ray diffraction data, which is advantageous for lowering the solidification cracking susceptibility. Moreover, all as-fabricated alloys present a typical strong fibre-type (200) crystallographic bulk texture measured by neutron diffraction, while such texture was relatively weaker in the lowest heat input condition. This work provides a reliable approach for stable additive manufacturing of Hastelloy C276 alloy, and innovatively presents rationales of stabilised properties based on the obtained insights into microstructure and bulk texture developments in a wide observation range by various techniques.