Quaternary Elements Research Articles

Multifunctional Structure-Modified Quaternary Compounds Co9Se8-CuSe2-WSe2 Mixed with MWCNT as a Counter Electrode Material for Dye-Sensitized Solar Cells.

In this study, a trimetallic selenide material with a hollow spherical structure (Co9Se8-CuSe2-WSe2) was synthesized through two consecutive solvothermal reactions. The synergistic effect between the quaternary elements, the benefits of the selenization of metals, and the unique morphology led to the prominent electrocatalytic ability of Co9Se8-CuSe2-WSe2 hollow spheres. Co9Se8-CuSe2-WSe2 hollow spheres were then mixed with oxygen plasma-treated multiwalled carbon nanotubes (MWCNT) as counter electrode (CE) material for dye-sensitized solar cells (DSSCs), achieving a photoelectric conversion efficiency (η) of 9.23% under one sun condition (AM 1.5G, 100 mW cm-2), surpassing the 8.08% of devices with platinum counter electrodes (PtCEs). For indoor conditions, a T5 light source was applied to the DSSCs with Co9Se8-CuSe2-WSe2 + MWCNT CE, and the efficiency increased to 14.14% under 3600 lx irradiance. Finally, Co9Se8-CuSe2-WSe2 + MWCNT CE demonstrated good stability with 92.23% retention after 1000 cycles of cyclic voltammetry, exceeding the 82.49% of PtCE. Therefore, Co9Se8-CuSe2-WSe2 + MWCNT shows potential as a substitute for platinum as CE material for DSSCs.

CC+ : A searchable database of validated coiled coils in PDB structures and AlphaFold2 models.

α-Helical coiled coils are common tertiary and quaternary elements of protein structure. In coiled coils, two or more α helices wrap around each other to form bundles. This apparently simple structural motif can generate many architectures and topologies. Coiled coil-forming sequences can be predicted from heptad repeats of hydrophobic and polar residues, hpphppp, although this is not always reliable. Alternatively, coiled-coil structures can be identified using the program SOCKET, which finds knobs-into-holes (KIH) packing between side chains of neighboring helices. SOCKET also classifies coiled-coil architecture and topology, thus allowing sequence-to-structure relationships to be garnered. In 2009, we used SOCKET to create a relational database of coiled-coil structures, CC+ , from the RCSB Protein Data Bank (PDB). Here, we report an update of CC+ following an update of SOCKET (to Socket2) and the recent explosion of structural data and the success of AlphaFold2 in predicting protein structures from genome sequences. With the most-stringent SOCKET parameters, CC+ contains ≈12,000 coiled-coil assemblies from experimentally determined structures, and ≈120,000 potential coiled-coil structures within single-chain models predicted by AlphaFold2 across 48 proteomes. CC+ allows these and other less-stringently defined coiled coils to be searched at various levels of structure, sequence, and side-chain interactions. The identified coiled coils can be viewed directly from CC+ using the Socket2 application, and their associated data can be downloaded for further analyses. CC+ is available freely at http://coiledcoils.chm.bris.ac.uk/CCPlus/Home.html. It will be updated automatically. We envisage that CC+ could be used to understand coiled-coil assemblies and their sequence-to-structure relationships, and to aid protein design and engineering.

Microstructural design for achieving high performances in Ti-V-Al lightweight shape memory alloys by optimizing Zr content

In the present study, the quaternary Zr element was introduced to replace Ti in Ti-V-Al based shape memory alloys. The addition of Zr element resulted in the microstructural features of Ti-V-Al based shape memory alloys, such as the phase evolution of αˊˊ → β, the precipitation of C14-type Laves phase, reduction of grain size etc. Moreover, the two-stage martensitic transformation corresponding to ω → β and αˊˊ → β transformation gradually evolved into single ω → β martensitic transformation during heating process in Ti-V-Al based shape memory alloys, as Zr content was increased from 0.5 at.% to 5.0 at.%, which was firstly reported in Ti-V-Al based shape memory alloys. Meanwhile, the martensitic transformation temperatures of Ti-V-Al based shape memory alloys were decreased with Zr increasing. By optimizing Zr content, the highest yield strength and largest microhardness can be gained in Ti-V-Al based shape memory alloy with controlling 5.0 at.% Zr, as a result of solution strengthening, grain refinement and precipitation strengthening. Besides, the moderate Zr content caused the precipitation of C14-type Laves phase and formed the quasi-continuous network structure, which contributed to the superior elongation. And the perfect fracture ductility with an elongation of 40% in the present Ti-V-Al based shape memory alloys with 3.0 at.% Zr was significantly larger than that the other reported Ti-V-Al based shape memory alloys. Moreover, the superior strain recovery characteristics with a fully recoverable strain of 4% can be achieved in Ti-V-Al based shape memory alloys through controlling 3.0 at.% Zr.

A two-dimensional grating surface made of quaternary Huygens elements excited by a real source

In this article, a new method to create an anomalous reflection in the desired direction is proposed. Two-dimensional grating surfaces consisting of four particles with the properties of a Huygens source are employed in each period. Then, this method is extended to the problem in which the grating surface is illuminated by a real source such as a horn. In this case, the designed grating surface has different periods in both directions to collimate the reflected wave and give an in-phase wavefront. Using our method, a high-efficiency reflectarray (RA) based on quaternary Huygens grating is designed. This RA is distinguished from common RAs due to its beam squint capability. This array offers more aperture efficiency and thus more gain in comparison to the leaky waves that inherently have low aperture efficiency. Therefore, our designed RA can compete with leaky wave antennas in many applications. The mentioned RA is designed to have the main beam in the direction of left( {{theta _0} = {{68}^{circ }},{varphi _0} = {{225}^{circ }}} right), at the frequency of 12 GHz. The simulation results show the realized gain and SLL of this antenna are 24.8 dB and -15.5 dB, respectively. Also, by changing the frequency in the range of 12–15 GHz, the direction of the main beam varies from left( {{{68}^{circ }}, {{225}^{circ }}} right) to left( {{{39}^{circ }}, {{225}^{circ }}} right).

In situ analysis of the Portevin-Le Chatelier effect from low to high-entropy alloy in equal HfNbTaTiZr system

The HfNbTaTiZr system is designed from low-entropy to high-entropy by unary, binary, ternary, quaternary, and quinary equal-molar element alloys. At first, the effect of mixing entropy on elevated temperature tensile behaviors ranging from 400 °C to 800 °C and strain rate 1 × 10−4 s–1 in body-centered-cubic (BCC) alloys is systematically discussed, including dynamic strain aging, serration behavior and in-situ deformation behavior of Portevin-Le Chatelier (PLC) band analysis. The results show that in BCC high-entropy alloys (HEAs), with the increase of the alloy elements, the range of the transition temperature of PLC bands expands, and the degree of dynamic strain aging at high temperature also enhances. The theoretical model was verified with the critical strain of unary, binary, and ternary alloys, and it predicts the PLC effect under the specific temperature and strain rate. Apply Applied to quinary alloys, the difference in serration phenomena between face-centered-cubic (FCC) and BCC HEA are investigated, showing that the high melting point of Nb and Ta elements lead to the slower self-adjusting velocity in HfNbTaTiZr alloy. Digital image correlation analysis is in-situ to analyze different types of PLC bands at various strain rates from 1 × 10–2 to 1 × 10−3 s–1 and elevated temperature from 200 °C to 600 °C. The BCC single-phase HEA reveals the transmission properties of the PLC bands and it is consistent with the serration behavior in the tensile stress-strain curve.

Experimental investigation on fracture toughness of Cu-based shape memory alloys with silver addition

An attempt is made in the present work to determine the fracture toughness of shape memory alloys by the addition of Ag as a quaternary element. Cu-Al-Mn-Ag shape memory alloys are synthesized by using a bottom pouring type casting machine. Three samples are prepared by varying the Ag concentration by 2%, 4%, and 6% (wt.%) and keeping the Mn content constant (2 wt%). After preparing the samples, they are homogenized in a muffle furnace at 850 °C to achieve the required strength and homogeneity. Single-edged crack specimens are prepared and a three-point bend test was conducted on Universal Testing Machine (UTM) as per ASTM standards. The stress Intensity Factor (KIC) is calculated using an empirical formula. It is observed from the experimental results that Stress Intensity Factor increases with an increase in Ag concentration. Microstructural analysis is conducted using Image Analyzer Microscope. It is observed there is a decrease in grain size with an increase in Ag concentration. According to XRD data, a change in Ag concentration does not significantly alter the size of the crystallites.

Effect of doping IVB, VB and VIB elements on structure, stability, elastic and electronic properties of the O and B2 of Ti2AlNb intermetallic: A first principles study

The intermetallic stability, structural, and elastic properties of the B2 and the O intermetallic of Ti2AlNb intermetallic doped with IVB, VB, and VIB elements of the periodic table are studied using density functional theory. The energy of formation and calculated elastic constants reveal that all the doped intermetallics are thermodynamically and mechanically stable. The derived elastic moduli and Pugh's ratio confirm that doping with quaternary elements can enhance the mechanical properties and ductility of the Ti2AlNb intermetallic in both the B2 and the O intermetallic. Further, elements that enhance the ductility and hardness in the O intermetallic, decrease the same in the B2 intermetallic. Among all the systems, Mo and W provide the most enhancement in B, G, and E values in both the B2 and O intermetallic. Ductility of the B2 intermetallic is most enhanced by Ti and Nb while of the O intermetallic by Cr and Mo. All the dopants increase the melting point where W provides the most enhancement. Poisson's ratio, hardness, and Cauchy pressures are further investigated. The electronic density of states indicates that dopants induce redistribution of charge due to new bond formations resulting to a significant change in intermetallic stability and mechanical properties.

Combined ab initio and experimental screening of phase stabilities in the Ce-Fe-Ti- X system ( X=3d and 4d metals)

One of the main challenges for the synthesis and application of the promising hard-magnetic compound $\mathrm{Ce}{\mathrm{Fe}}_{11}\mathrm{Ti}$ is the formation of Laves phases that are detrimental for their thermodynamic stability and magnetic properties. In this paper, we present an ab initio based approach to modify the stability of these phases in the Ce-Fe-Ti system by additions of $3d$ and $4d$ elements. We combine highly accurate free-energy calculations with an efficient screening technique to determine the critical annealing temperature for the formation of $\mathrm{Ce(Fe,X)}{}_{11}\mathrm{Ti}$. The central findings are the dominant role of the formation enthalpy at $T=0$ K on chemical trends and the major relevance of partial chemical decompositions. Based on these insights, promising transition metals to promote the stability of the hard-magnetic phase, such as Zn and Tc, were predicted. The comparison with suction casting and reactive crucible melting experiments for Ce-Fe-Ti-X (X = Cu, Ga, Co, and Cr) highlights the relevance of additional phases and quaternary elements.

Effect of alloying elements (Nb, Ag) on the damping performance of Cu–Al–Mn shape memory alloys

This study investigates the damping properties of Cu–Al–Mn shape memory alloys (SMAs) with various chemical compositions and the effects of the addition of quaternary alloying elements Ag and Nb on the microstructure, martensitic transformation behavior, and damping capacity of SMAs. Compared to other Cu–12Al–xMn (x = 4–7 wt%) SMAs, Cu–12Al–5Mn has a more significant inherent and intrinsic internal friction (IFPT + IFI) peak above room temperature. The addition of Ag or Nb to Cu–12Al–5Mn reduced the grain size, thereby increasing the hardness of the alloys; however, the damping capacity and temperature of the IFPT + IFI peak decreased simultaneously. The addition of Ag to Cu–12Al–5Mn significantly reduced the damping capacity (IFPT+IFI peak) because of the notable decrease in the amount of transformed martensite. Moreover, the addition of Nb to Cu–12Al–5Mn caused the AlNb3 phase to precipitate, limiting the mobility of the martensite variant interfaces and slightly decreasing the damping capacity (IFPT + IFI peak). Among the Ag- and Nb-doped Cu–12Al–5Mn SMAs, Cu–12Al–5Mn–1 Nb showed not only a significantly higher hardness but also a higher IFPT + IFI peak, with tan δ exceeding 0.01 at approximately 50 °C.

Effect of Ni and Mn additions on the damping characteristics of Cu-Al-Fe based high temperature shape memory alloys

Shape Memory Alloys (SMAs) are smart materials that involve a transition from the martensitic phase to the austenitic phase when induced by a change in temperature or stress. SMAs have been proven to possess damping properties, which is caused by the internal friction that occurs in the martensitic phase. This work focuses on exploring the damping properties of some copper-based ternary and quaternary SMAs using Dynamic Mechanical Analysis (DMA) by calculating internal friction. The results show that the peak value of damping lies near to the martensitic start temperature of the respective alloys. The addition of quaternary elements (Ni and Mn) to the existing ternary alloy decreases the transformation temperatures, thereby decreasing the temperature at which the peak damping value occurs. The Ni-Ti alloy attains its peak value of damping at temperatures lower than the temperatures at which peak value is attained for these alloys. Therefore, the results prove that the alloys developed are promising materials for damping applications which can be used over a wide range of temperatures.

Correction: Experimental investigation of the effects of different quaternary elements (Ti, V, Nb, Ga, and Hf) on the thermal and magnetic properties of CuAlNi shape memory alloy

Correction: Experimental investigation of the effects of different quaternary elements (Ti, V, Nb, Ga, and Hf) on the thermal and magnetic properties of CuAlNi shape memory alloy

Experimental investigation of the effects of different quaternary elements (Ti, V, Nb, Ga, and Hf) on the thermal and magnetic properties of CuAlNi shape memory alloy

Experimental investigation of the effects of different quaternary elements (Ti, V, Nb, Ga, and Hf) on the thermal and magnetic properties of CuAlNi shape memory alloy

Comparison of binary, ternary and quaternary shape memory alloys and techniques to enhance their mechanical properties: A focused review

Shape memory alloys (SMAs) are smart materials having an ability to remember the original shape when deformed at the temperatures below martensite finish (Mf), which can be recovered up to certain extent by heating these alloys to temperatures above austenite finish (Af). SMAs find wide applicability in engineering sectors including automotive, aerospace, and biomedical. Prior to fabrication of any sensors and actuators using SMA, it is recommended to have an extensive simulation study that requires material properties as a prime input to the software. Scattered literature on SMA’s material properties make this challenging for new researchers. This paper presents a review of binary, ternary and quaternary alloys exhibit shape memory effect and their comparison in terms of transformation temperatures and mechanical properties. It also comments on effects in their properties due to addition of ternary and quaternary elements. Impact of thermomechanical treatments to enhance the mechanical properties and shape recovery characteristics of SMAs is reviewed. The study concludes with signifying the use of processing techniques in enhancing mechanical properties of SMAs for their utilization in possible sensing applications.

Effect of Quaternary Element (Ni and Mn) Additions on Structural and Magnetic Properties of Cu-Based Alloys

We investigated the quaternary Cu-25.49%Zn-7.68%Al-3.44%Ni and Cu-26.03%Zn-6.31%Al-2.73%Mn (wt. %) alloys according to their structural and magnetic properties. For structural observations, we employed X-ray diffraction (XRD), scanning electron microscope (SEM), and electron dispersion spectroscopy (EDS) techniques to study. The magnetic properties of alloys were characterized as a function of temperature (T) and applied external magnetic field (H) by using Physical Properties Measurement System (PPMS) magnetometry. According to SEM and XRD observations, the existing microstructures consist of two types of precipitates that are namely α and intermetallic κ-phases in CuZnAlNi alloy. We also observed the austenite phase in CuZnAlMn alloy. The M-H magnetization curves exhibited obvious paramagnetic behavior for the examined alloys. Although Ni and Mn elements have similar magnetic nature, they show different magnetic characteristics with different structures.

Combinatorial Synthesis and High-Throughput Characterization of Microstructure and Phase Transformation in Ni–Ti–Cu–V Quaternary Thin-Film Library

Abstract Ni–Ti–based shape memory alloys (SMAs) have found widespread use in the last 70 years, but improving their functional stability remains a key quest for more robust and advanced applications. Named for their ability to retain their processed shape as a result of a reversible martensitic transformation, SMAs are highly sensitive to compositional variations. Alloying with ternary and quaternary elements to fine-tune the lattice parameters and the thermal hysteresis of an SMA, therefore, becomes a challenge in materials exploration. Combinatorial materials science allows streamlining of the synthesis process and data management from multiple characterization techniques. In this study, a composition spread of Ni–Ti–Cu–V thin-film library was synthesized by magnetron co-sputtering on a thermally oxidized Si wafer. Composition-dependent phase transformation temperature and microstructure were investigated and determined using high-throughput wavelength dispersive spectroscopy, synchrotron X-ray diffraction, and temperature-dependent resistance measurements. Of the 177 compositions in the materials library, 32 were observed to have shape memory effect, of which five had zero or near-zero thermal hysteresis. These compositions provide flexibility in the operating temperature regimes that they can be used in. A phase map for the quaternary system and correlations of functional properties are discussed with respect to the local microstructure and composition of the thin-film library.

Chemical vapor deposition of TiN on a CoCrFeNi multi-principal element alloy substrate

The reactivity of a quaternary multi-principal element alloy (MPEA), CoCrFeNi, as a substrate in thermal halide chemical vapor deposition (CVD) processes for titanium nitride (TiN) coatings was studied. The coatings were deposited at 850 °C–950 °C using TiCl4, H2 and N2 precursors. The coating microstructures were characterized using X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM/TEM) with energy dispersive X-ray spectroscopy (EDS). Thermodynamic calculations of substrate and coating stability for a gas phase environment of N2 and H2 within a temperature range relevant for the experiments showed that Cr is expected to form hexagonal Cr2N and cubic (Ti1−ε1Crε1)N or (Cr1−ε2Tiε2)N phases. These phases could however not be discerned in the samples by XRD after the depositions. Cr was detected at the grain boundaries and the top surface by EDS for a sample synthesized at 950 °C. Grain boundary and surface diffusion, respectively, were the suggested mechanisms for Cr transport into the coating and onto the top surface. Although thermodynamic calculations indicated that Cr is the most easily etched component of the CoCrFeNi alloy to form gaseous chlorides in similar concentrations to that of the residual Ti-chlorides, no sign of etching were found according to the imaging of the sample cross-sections using SEM and TEM. Cross-section and top surface images further confirmed that the choice of substrate had no significant detrimental influence on the film growth or microstructure.

Nuclear phylogeography of the temperate tree species Chiranthodendron pentadactylon (Malvaceae): Quaternary relicts in Mesoamerican cloud forests

BackgroundThe Mexican hand tree or Canac (Chiranthodendron pentadactylon) is a temperate tree species of cloud and pine-oak forests of southern Mexico and Guatemala. Its characteristic hand-shaped flower is used in folk medicine and has constituted the iconic symbol of the Sociedad Botánica de México since 1940. Here, the evolutionary history of this species was estimated through phylogeographic analyses of nuclear DNA sequences obtained through restriction site associated DNA sequencing and ecological niche modeling. Total genomic DNA was extracted from leaf samples obtained from a representative number (5 to 10 per sampling site) of individuals distributed along the species geographic range. In Mexico, population is comprised by spatially isolated individuals which may follow the trends of cloud forest fragmentation. By contrast, in Guatemala Chiranthodendron may constitute a canopy dominant species near the Acatenango volcano. The distributional range of this species encompasses geographic provinces separated by the Isthmus of Tehuantepec.The objectives of the study were to: (i) estimate its genetic structure to define whether the observed range disjunction exerted by the Isthmus of Tehuantepec translates into separate populations, (ii) link population divergence timing and demographic trends to historical climate change, and (iii) test hypotheses related to Pleistocene refugia.ResultsPatterns of genetic diversity indicated high levels of genetic differentiation between populations separated by the Isthmus. The western and eastern population diverged approximately 0.873 Million years ago (Ma). Demographic analyses supported a simultaneous split from an ancestral population and rapid expansion from a small stock approximately 0.2 Ma corresponding to a glacial period. The populations have remained stable since the LIG (130 Kilo years ago (Ka)). Species distribution modelling (SDM) predicted a decrease in potential distribution in the Last Interglacial (LIG) and an increase during the Last Glacial Maximum (LGM) (22 Ka), Mid-Holocene (6 Ka) and present times.ConclusionsDivergence time estimations support the hypothesis that populations represent Quaternary relict elements of a species with broader and northernmost distribution. Pleistocene climatic shifts exerted major influence on the distribution of populations allowing dispersion during episodes of suitable climatic conditions and structuring during the first interglacial with a time period length of 100 Kilo years (Kyr) and the vicariant influence of the Isthmus. Limited demographic expansion and population connectivity during the LGM supports the moist forest hypothesis model.

Metallurgical processes for hardening of 22Karat Gold for light weight and high strength jewelry manufacturing

The present work reports about the process developed for hardening 22Karat gold (Au-5.8wt.%Cu-2.5wt.%Ag). The present hardness of 22Karat gold is 85–90HV (Vickers scale). The target hardness aimed is 150HV in the final jewelry product, similar to the hardness of 18Karat gold, however without compromising luster and purity (91.7wt.%). Titanium is added as the quaternary element in micro concentrations that grain refines the as-cast structure of 22Karat gold and improves the strength of the cast jewelry products. On other hand the narrow solid solubility of Ti in Au is used to convert the 22Karat gold into age hardenable gold alloy suitable for making hand-made jewelry products. This paper reports the optimization of various process parameters in industrial scale, required for producing hard 22Karat gold containing Ti through age hardening process. In lab scale the titanium concentration required was optimized to 0.5wt.%, to obtain effective age hardenability in 22Karat gold was studied. In industry the melting and casting trials of 22Karat gold with the addition of 0.5wt.% of Ti to obtain maximum yield was performed. The annealing and cold-working operations were conducted to the Ti-22Karat gold that lead to production of hand-made bangles were studied. The age hardening treatments (Solutionizing and Artificial Aging (AA)) were conducted to the Ti-22Karat gold bangles to obtain hardness >150HV.

Study on the electrochemical behaviour of 22k gold (Au-5.8wt.%Cu-2.5wt.%Ag) and Ti containing 22k gold (Au-5.8wt.%Cu-2.0wt.%Ag-0.5wt.%Ti)

The electrochemical corrosion behaviour of 22k gold (Au-5.8wt.%Cu-2.5wt.%Ag) and Ti containing 22k (Ti-22k) gold (Au-5.8wt.%Cu-2.0wt.%Ag-0.5wt.%Ti) was studied. Elemental Ti was added as the quaternary element to 22k gold by replacing Ag, resulting in the formation of secondary phase precipitates during age hardening treatment, thereby improving the hardness of the alloy. Anodic polarization tests were conducted for both 22k and Ti-22k samples in their as-cast annealed, cold-rolled annealed and age-hardened conditions using 0.9% sodium chloride and 1% lactic acid as medium. The as-cast and annealed 22k samples showed better corrosion resistance in both corrosion media whereas the 22k samples in the cold-rolled, annealed condition and Ti-22k samples in the as-cast, annealed condition showed poor corrosion resistance. After age-hardening treatment, cold-rolled Ti-22k samples showed better corrosion resistance due to the formation of passive layer (of TiO2) on the surface. However, corrosion gets initiated in the age-hardened Ti-22k due to the breaking and decomposition of the passive layer (TiO2) at a potential > 1.3 V.

Thermodynamic and kinetic behavior of low-alloy steels: An atomic level study using an Fe-Mn-Si-C modified embedded atom method (MEAM) potential

A quaternary element Modified Embedded Atom Method (MEAM) potential comprising Fe, Mn, Si, and C is developed by employing a hierarchical multiscale modeling paradigm to simulate low-alloy steels. Experimental information alongside first-principles calculations based on Density Functional Theory served as calibration data to upscale and develop the MEAM potential. For calibrating the single element potentials, the cohesive energy, lattice parameters, elastic constants, and vacancy and interstitial formation energies are used as target data. The heat of formation and elastic constants of binary compounds along with substitutional and interstitial formation energies serve as binary potential calibration data, while substitutional and interstitial pair binding energies aid in developing the ternary potential. Molecular dynamics simulations employing the developed potentials predict the thermal expansion coefficient, heat capacity, self-diffusion coefficients, and stacking fault energy for steel alloys comparable to those reported in the literature.