Fcc Plane Research Articles

A fabrication process of soft magnetic Ni films electroplated from gel electrolyte

We have already reported some electroplated magnetic films using aqueous solutions. In the present study, we proposed a fabrication process for electroplated soft magnetic films (Ni films) using gel electrolytes. We added gelatin to the plating baths and confirmed that adding 22 g/L of gelatin enabled us to obtain gel electrolytes. Using the gel electrolytes, we electroplated Ni films and evaluated their structural and magnetic properties. From the evaluation of magnetic properties, we confirmed spontaneous magnetization of the Ni films prepared from the gel electrolyte. For obtaining thick Ni films (>1 μm), we investigated stirring the gel electrolyte during plating. As a result, we found that stirring increased the thickness, and our result suggests that stirring the gel electrolyte is useful to increase the deposition rate. In our experimental conditions, the deposition rate of the plating process was ∼0.25 μm/min. From XRD analysis, the structure of Ni films for gel electrolytes was oriented in the fcc (220) plane and slightly different from that for liquid electrolytes. From these results, we found that soft magnetic films could be obtained from the gel electrolyte and that gel plating is one of the attractive fabrication processes of the thick films.

Atomic simulations of the formation of twist grain boundary and mechanical properties of graphene/aluminum nanolaminated composites

In this paper, generation of twist grain boundaries (TGBs) and their effects on the mechanical behaviors of graphene/aluminum (Gr/Al) nanolaminated composites were studied via molecular dynamics (MD) method. Crystallization of the Gr/Al composite was conducted to observe the microstructural evolution. The whole evolution process including nucleation and growth of crystals was presented. TGBs were formed between the adjacent crystals after crystallization. The fcc (1 1 1) plane of the Al matrix has three-fold symmetry, so that the TGB angles can range from 0° to 60°. Tensile tests on the Gr/Al composites with TGBs were carried out to study their deformation behavior. The results showed that the graphene-nanoplate (GNP) and TGBs greatly impact on the dislocation behavior of the Al matrix. The dependences of dislocation nucleation and evolution on the TGB angle were uncovered. The TGB also plays a significant role in blocking dislocation motion, and the effectiveness mainly depends on its strength. The variations of yield stress and strain of the Gr/Al composites with different TGB angles were also predicted. It was revealed that failure of the composite is caused by combined action of tensile deformation and shear deformation induced by defects at the GNP edge.

Altered microstructural evolution and mechanical properties of CoCrFeNiMo0.15 high-entropy alloy by cryogenic rolling

In this paper, the microstructural characteristics and deformation behaviors of a CoCrFeNiMo0.15 high-entropy alloy (HEA) with a low volume fraction of σ precipitates during rolling deformation at cryogenic temperature and room temperature were investigated. The stacking fault energy of the HEA was experimentally estimated via measuring the widths of the dissociated dislocations. Deformations at two temperature conditions were both characterized by dislocation activities and extensive nano-twinning, while the rate of these microstructural evolution was accelerated with the aid of the cryogenic temperature. Abundant microbands, nanotwins and stacking faults were detected during deformation under both temperature conditions. Moreover, the hexagonal close-packed structure can only be observed in the cryogenic rolled sample, which was produced via the glide of Shockley partials on every other {111}FCC plane. At the late deformation stage of cryogenic rolling, the nanotwins were markedly distorted or even fractured, and shear bands were also formed. The contributions of different strengthening mechanisms of cryogenic rolling were discussed.

Deformation mechanisms of mechanically induced phase transformations in iron

Effects of uniaxial tensile directions on the phase transformations in a nano-sized face centred cubic (fcc) crystal in iron were studied by molecular dynamics simulations. The results show that externally applied loading induced phase transformations from fcc phase to body centred cubic (bcc) phase, and variant selection took place depending on the tensile direction relative to the crystallographic orientation of the fcc crystal. For the loading along the close packed fcc plane, the uniaxial tensile direction perpendicular to the close packed direction led to the formation of flat-ellipsoid bcc nuclei composed of {0 1 1} twinning martensite, while that parallel to the close packed direction resulted in zigzag bcc plates with the {1 1 2} twinning sub-structure. When the tensile loading was perpendicular to the close packed fcc planes, a number of stacking faults as a result of the movement of Shockley partial dislocations appeared temporarily in the shape of “funnels”, which distorted the fcc lattices severely before it transformed into the bcc phase. The deformation mechanisms of the mechanically induced phase transformations through twinning or dislocations revealed in the present study may provide clues to develop iron or iron-based shape memory alloys with both high strength and good ductility.

Mechanical properties and microstructural evolution of WC-binderless and WC-Co hard materials by the heat treatment process

In this study, the heat treatment process was performed to improve the mechanical properties of WC-binderless and WC-Co hard materials pre-fabricated by PCAS process. The microstructural and mechanical properties were varied significantly by the heat treatment process with the treatment time. To increase the fracture toughness value, the heat-treatment process of the WC-binderless, WC-5 wt.% Co and WC-10 wt% Co hard materials were performed at (1,300, 1,150, and 950) °C under (5 and 48) h, respectively. Enhancement of fracture toughness that focused on the major reasons was estimated for four mechanisms. Firstly, the microstructure formation of a mechanism was investigated to demonstrate the grain coarsening behavior for variation of heat treatment time. Secondly, the fraction of the coherent interface at WC/Co to the existing in the specific plane orientation was investigated. In particular, the texture distribution of WC (0001)hcp plane and Co (111)fcc plane were discussed in the EBSD micrograph. Thirdly, the increase of the mean free path by the Co content was exhibited in relation to the variation of mechanical properties. Finally, the mechanism of the decarburization effect of WC, which occurs during the heat treatment process under specific condition were demonstrated in the XRD peaks and FE-SEM analysis. In this chemical reaction, the separated W phases were locally precipitated, resulting in an increase in fracture toughness.

Deformation induced FCC lamellae and their interaction in commercial pure Ti

Titanium with hexagonal close-packed (hcp) structure can undergo phase transformation to face-centered cubic (fcc) structure under mechanical straining at room temperature. In this work, we identified two orientation relationships (ORs) between fcc phase and hcp matrix in commercial pure Ti, i.e., P-type OR [1¯21¯0]hcp||[11¯0]fcc and (101¯0)hcp||(110)fcc, and B-type OR [1¯21¯0]hcp||[11¯0]fcc and (0001)hcp||(1¯1¯1)fcc. The P-type interface is flat while the B-type interface is stepped, which are ascribed to the pure-shuffle mechanism and the partial gliding mechanism, respectively. Most intriguingly, the B-type fcc lamella can penetrate the P-type fcc lamella through gliding of the dislocation with Burgers vector ½[110] on (001)fcc plane.

Green synthesis, antibacterial, antioxidant and cytotoxic effect of gold nanoparticles using Pistacia Atlantica extract

Abstract A simple, affordable and ecofriendly method for synthesis gold nanoparticles (Au NPs) using Pistacia Atlantica (leave and fruit) extract at the room temperature, has been carry out in the present study. Higher reaction rate about a minute is so noticeable and Au NPs synthesis with this method provided nontoxic carrier for application. Various analytical technique including UV–vis absorption spectroscopy approved presence of Au NPs in the solution, the functional groups of Pistacia Atlantica extract in the reduction and capping process of Au NPs is determined by FT-IR, crystallinity with the fcc plane approved from the X-ray diffraction (XRD) pattern, energy dispersive spectroscopy (EDS) determined existence of elements in the sample, surface morphology, diverse shapes and size of present Au NPs were showed by using scanning electron microscopy (SEM), atomic force microscopy (AFM) and Transmission electron microscopy (TEM). In addition, antibacterial, antioxidant and cytotoxicity properties of Au NPs were studied. Agar disk and agar well diffusion are the methods to determined antibacterial properties of synthesized Au NPs. Also MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) were recognized by macro broth dilution assay. DPPH free radical scavenging assay was used for antioxidant property and compare to butylated hydroxytoluene (BHT) as standard antioxidant. Synthesized Au NPs have great cell viability in a dose depended manner and demonstrate that this method for synthesis Gold nanoparticles provided nontoxic. The average diameter of synthesized Au NPs was about 50–60 nm.

Green synthesis and characterizations of gold nanoparticles using Thyme and survey cytotoxic effect, antibacterial and antioxidant potential

Nowadays, green chemistry methods are noticeable for synthesis metal nanoparticles due to affordable, easy and high reaction rate. In the present study gold nanoparticles (Au NPs) were eco-friendly synthesized using Thyme extract at the room temperature for 30 min to provide non-toxic, which can be used for different applications. Identifying properties of synthesized gold nanoparticles was done by various analytical technique including UV–Vis absorption spectroscopy approved presence of Au NPs in the solution, the functional groups of Thyme extract in the reduction and capping process of Au NPs are determined by FT-IR, Crystalline with the fcc plane approved by X-ray diffraction (XRD) pattern, energy dispersive spectroscopy (EDS) determined existence of elements in the sample, surface morphology, diverse shapes and size of present Au NPs were showed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Transmission electron microscopy (TEM). Beginning and end destroy temperature of the gold nanoparticles were determined by thermal gravimetric spectroscopy (TGA). In addition, antibacterial, antioxidant, and cytotoxicity properties of Au NPs were studied. Antibacterial activity of Au NPs was investigated on gram-positive (Bacillus) and gram-negative (Escherichia coli) by disk diffusion; also MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) were determined. DPPH free radical scavenging assay was used for antioxidant property and compared to butylated hydroxy toluene (BHT) as a standard antioxidant that showed high antioxidant activity. Synthesized Au NPs have great cell viability in a dose-depended manner and demonstrate that this method provided nontoxic for synthesis gold nanoparticles. The average diameter of synthesized Au NPs was about 35 nm.

Green synthesis of Au nanoparticles using an aqueous extract of Stachys lavandulifolia and their catalytic performance for alkyne/aldehyde/amine A3 coupling reactions.

High reaction rate and easy availability make green synthesis of metal nanoparticles noticeable. In the present study, gold nanoparticles with wide applications in different fields were synthesized by an ecofriendly method at room temperature using Stachys lavandulifolia extract as the reducing agent. Properties of the synthesized gold nanoparticles (GNP) were identified by different analytical techniques including: UV-Vis absorption spectroscopy verified presence of Au NPs in the solution while functional groups of its extract and synthesized Au NPs were determined by FT-IR. Its crystalline analysis with a fcc plane was verified by X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) determined elements in the sample. Surface morphology, diverse shapes and sizes of the Au NPs were shown by scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Beginning and end destruction temperatures of the Au/S. lavandulifolia NPs were determined by thermal gravimetric analysis (TGA). The Au nanoparticles were capped with extracts, preventing them from oxidation and agglomeration and were used as an efficient heterogeneous nanocatalyst for a three-component reaction of amines, aldehydes, and alkynes (A3 coupling). A diverse range of propargylamines were obtained in good yields. Furthermore, the separation and recycling of Au/S. lavandulifolia NPs was very simple, effective, and economical.

Vacancy enhanced formation and phase transition of Cu-rich precipitates in α - iron under neutron irradiation

In this paper, we employed both molecular statics and molecular dynamics simulation methods to investigate the role of vacancies in the formation and phase transition of Cu-rich precipitates in α-iron. The results indicated that vacancies promoted the diffusion of Cu atoms to form Cu-rich precipitates. After Cu-rich precipitates formed, they further trapped vacancies. The supersaturated vacancy concentration in the Cu-rich precipitate induced a shear strain, which triggered the phase transition from bcc to fcc structure by transforming the initial bcc (110) plane into fcc (111) plane. In addition, the formation of the fcc-twin structure and the stacking fault structure in the Cu-rich precipitates was observed in dynamics simulations.

Molecular Dynamics Study of Adatom Size Effect on Stress Evolution in Lennard-Jones Thin Films: X-Ray Scattering Analysis

Molecular dynamic simulations are used to study the structure and the evolution of stress during the deposition of atoms with different size on the (001) FCC plane. The relative size of deposited atoms is changed in the range from 0.75 to 1.0. To calculate the X-ray scattering profiles we applied the model that is based on the kinematical scattering theory. Deformation of the lattice parameters in deposited layers were directly determined by the analysis of X-ray diffraction profiles. It was found that the crystal lattice near the surface exhibits a major influence on the stress evolution. The deposited atoms form the same structure in entire systems, regardless of the their relative size.

Interlayer potentials for fcc (1 1 1) planes of Pd–Ag random alloys

Using ab initio alloy theory in combination with the Chen-Möbius inversion method, we obtain the interaction potentials between layers of the face centered cubic (fcc) (111) plane family for elemental Pd and Ag metals and for Pd0.5Ag0.5 random alloy. Based on the interlayer potentials, we investigate properties related to the fcc (111) planes, such as the stacking fault energy, shear elastic constant, surface energy, surface relaxations, and phonon dispersion along the fcc [111] direction. The results agree well with those obtained by fully self-consistent ab initio calculations and also with the available experimental data, indicating that the properties related to the close-packed planes are well described by the interlayer potentials.

Atomistic simulation of fcc—bcc phase transition in single crystal Al under uniform compression

By molecular dynamics simulations employing an embedded atom model potential, we investigate the fcc-to-bcc phase transition in single crystal Al, caused by uniform compression. Results show that the fcc structure is unstable when the pressure is over 250 GPa, in reasonable agreement with the calculated value through the density functional theory. The morphology evolution of the structural transition and the corresponding transition mechanism are analysed in detail. The bcc (011) planes are transited from the fcc (111̄) plane and the (11̄1) plane. We suggest that the transition mechanism consists mainly of compression, shear, slid and rotation of the lattice. In addition, our radial distribution function analysis explicitly indicates the phase transition of Al from fcc phase to bcc structure.

A novel potential: the interlayer potential for the fcc (111) plane family

We propose a novel interlayer potential, which is different from usual interatomic potentials. The interlayer potential represents the interaction between atomic layers in a layered material. Based on the Chen–Möbius inversion method in combination with ab initio calculations, the interlayer interactions are obtained for the face centered cubic (fcc) (111) planes. In order to check the validity of our interlayer potential, we calculate the intrinsic stacking fault energy (γsf) and the surface energy (γs) of five metals: Al, Ni, Cu, Ag and Au. The predicted γsf and γs values are compared with the theoretical results obtained from direct calculations and also with the available experimental data. Using the interlayer potentials, we also investigate the phonon dispersion and phonon density of state in the fcc (111) plane family of the considered metals.

Synthesis of AgNPs using the extract of Calotropis procera flower at room temperature

This paper describes green procedure for the synthesis of silver nanoparticles (AgNPs) using the extract of Calotropis procera flower. The aqueous extract of this flower has been used as green reducing and stabilizing agent. Parameters such as pH and reaction time were varied. Progress of the reaction has been monitored by surface plasmon resonance of AgNPs, which occur at 405 nm. Raman spectra revealed the unique surface enhancing property of synthesized AgNPs. XRD pattern of AgNPs confirms the crystallinity with fcc plane. The average particle size of synthesized AgNPs was found to be in the order of 35 nm. SEM analysis revealed well defined shape of AgNPs. SEM with EDX spectrum authenticated the presence of silver. FT-IR spectra indicate that synthesized AgNPs were capped with phytochemicals present in the extract. The cubical shape of AgNPs was obtained. This greener synthesis is achieved at room temperature and found to be reproducible.

Reflection High-Energy Electron Diffraction Characterization of Cobalt Clusters Electrodeposited on a Au(100) Electrode

Cobalt was electrodeposited onto a reconstructed Au(100) electrode in 0.25 M Na2SO4 + 0.1 mM CoSO4 under potentiostatic conditions. The Au(100) electrode loaded with the Co deposit was transferred via an argon environment to ultrahigh vacuum and subsequently examined with reflection high-energy electron diffraction (RHEED). The resultant RHEED results were analyzed in detail to unveil the structures of the as-prepared Co deposit, which assumed nanometer-sized clusters on the Au(100) substrate. Aided by coulometric results, profile analysis of the RHEED results indicated that the Co clusters on average were 3 nm in width and 15 atomic layers in height. The packing habits of the Co clusters, determined by the obtained RHEED results, were the face-centered cubic (fcc) phase, rather than the hexagonal closed-packed (hcp) phase. Cobalt clusters grew with their fcc (1̅10) plane aligned parallel to the Au(100) substrate and with their [110] axis aligned in the [011] direction of the Au(100) substrate. The preferential growth of the fcc Co phase is driven by the optimal lattice match between the (1̅10) plane of Co clusters and the Au(100) substrate network.

The different effects of asymmetric rolling and surface friction on formation of shear texture in aluminium alloy AA5754

Conventional rolling and asymmetric rolling (ASR) processes were applied to aluminium alloy AA5754 with different roll metal frictional conditions. The rolling textures were determined by X-ray diffraction technique and the formation of shear texture was studied. It has been demonstrated that the ASR and friction have different effects on the generation of shear texture. The ASR forces the deformation texture to rotate about the transverse direction from the fcc plane strain compression texture, while a high friction generates a so called ideal fcc shear texture consisting of the {001}〈110〉 and {111}〈uvw〉 components. The effect of ASR penetrates throughout the sheet thickness, but that of friction exists only from the sheet surface to one-quarter thickness.

A formulation for the characteristic lengths of fcc materials in first strain gradient elasticity via the Sutton–Chen potential

The usual continuum theories are inadequate in predicting the mechanical behavior of solids in the presence of small defects and stress concentrators; it is well known that such continuum methods are unable to detect the change of the size of the inhomogeneities and defects. For these reasons various augmented continuum theories and strain gradient theories have been proposed in the literature. The major difficulty in implication of these theories lies in the lack of information about the additional material constants which appear in such theories. For fcc metals, for the calculation of the associated characteristic lengths which arise in first strain gradient theory, an atomistic approach based on the Sutton–Chen interatomic potential function is proposed. For the validity of the computed characteristic lengths, the phenomenon of the size effect pertinent to a nano-sized circular void within an fcc (111) plane is examined via both first strain gradient theory and lattice statics. Comparison of the results explains the physical ramifications of the characteristic lengths in improving the usual continuum results. Moreover, by reconsideration of the Kelvin problem it is shown that a commonly employed variant of the first strain gradient theory is only valid for a few fcc metals.

Origin of Self-Regulated Cluster Growth on the TiO2(110) Surface Studied Using Polarization-Dependent Total Reflection Fluorescence XAFS

Three-dimensional structures of Ni clusters deposited on a TiO2(110) surface were studied using polarization-dependent total reflection fluorescence X-ray absorption fine structure (PTRF-XAFS) analysis. Three-dimensional Ni clusters were formed with a slightly anisotropic structure at 1 × 1014 atoms/cm2. The PTRF-XAFS results for a 1 × 1014 atoms/cm2 sample revealed the formation of one-atomic-layer Ni clusters with a distorted (110)fcc plane structure. We found a Ni−Ni distance of 0.240 nm with Ni−O interaction at 0.23 nm. The structure was stabilized by interaction of surface oxygen atoms. The origin of cluster size self-regulation was the strong Ni−O interaction and matching of the crystal lattice between TiO2(110) and distorted Ni(110) structures.

Experimental study of the photonic band structure of synthetic opals at a low dielectric contrast

This paper reports on a comprehensive study of optical transmissivity spectra of synthetic opals as a function of the four major parameters of the observed photonic stop bands, namely, light beam orientation relative to the opal fcc lattice, light polarization, opal-filler dielectric permittivity contrast, and sample thickness. The measurements were performed under low opal-filler dielectric contrast conditions for the principal high-symmetry directions of the twinned fcc lattice of the opals. The experimentally determined dependence of the energy positions of photonic stop bands on the direction of the light wave vector is fitted well by the calculated dispersion relation of Bragg wavelengths in diffraction of light from the (hkl) fcc plane system.