Cr Composition Research Articles

Shelf-to-basin shuttle of highly fractionated chromium isotopes in the Arctic Ocean

The oceanic chromium (Cr) cycle is mainly governed by the interconversion and the distribution of Cr(VI) and Cr(III) species and their stable isotopic ratios (δ53Cr) in the water column. As a result, the Cr cycle generates a strong correlation between the natural logarithm of its dissolved concentration and δ53Cr regardless of the location of sampling. A few studies have reported the Cr composition of certain regions falling off the global Cr array, highlighting the local prevalence of underlying mechanisms participating in the Cr cycle in the oceans. In an effort to better constrain the global Cr array, this study presents an extensive dataset for total dissolved Cr concentration ([Cr]T) and δ53Cr in the Arctic Ocean in regions meeting the environmental conditions where Cr was observed to fall off the global Cr array (e.g. continental shelves, restricted water circulation, sea ice melting). We find that more than 70% of the Arctic seawater collected plot below the global Cr array due to a small addition of highly fractionated Cr (−2.8 ‰ to −1.1 ‰) and its transport across all the Arctic regions sampled. We identify the Chukchi Shelf as the region where highly fractionated Cr is produced, from where a Cr shuttle could work in tandem with the Arctic Fe and Mn shuttles to explain the production and widespread export of isotopically light Cr in the Arctic waters. We identify a second non-reductive release of highly fractionated Cr in the Canadian Arctic Archipelago, Baffin Bay and potentially the Labrador Sea via sediment resuspension, alongside addition of isotopically light Cr originating from crustal rocks. These findings demonstrate that the Arctic-modified outflow signature of Cr isotopes modify the Cr isotopic signature of the North Atlantic waters, and that the North Atlantic waters may deviate from the global Cr array depending on whether the isotopically light Cr added to the Arctic Ocean is Cr(III) that has not been scavenged or Cr(III) that has oxidized to Cr(VI).

Corrosion behavior of additively manufactured FeCrAl in out-of-pile light water reactor environments

Iron-Chromium-Aluminum (FeCrAl) alloys are candidate materials for the cladding of light water reactor (LWR) fuels. The FeCrAl alloys in general range in Cr composition from 12% (C26M) to 21% (APMT). In this work, the general corrosion behavior of Additively Manufactured (AM) C26M coupons was compared to the behavior of traditional Powder Metallurgy (PM) coupons. Immersion testing were conducted for 12 months at 288 °C and 330 °C in pure water containing either oxygen or hydrogen. Results show that the mass change of AM specimens in hydrogenated water was like the mass change of PM specimens. In oxygenated water, the mass change of AM coupons was higher and less reproducible than for the PM coupons. Porosity in the AM specimens makes their behavior less predictable in high-temperature water.

Systematic experimental and model-based evaluation of the synergistic effects of alloy composition and damage rate on the formation of Cr-rich precipitates in Fe–Cr–Al alloys under ion irradiation

Fourteen Fe–Cr–Al alloys with systematically varied Cr and Al compositions were irradiated at 350∘C to 0.24 dpa by 10.5 MeV self-ions as model alloys for the Fe–Cr–Al (oxide dispersion strengthened: ODS) alloys being developed as accident tolerant fuel (ATF) cladding for light water reactors. Three dose rates (8×10−6, 8×10−5, and 8×10−4 dpa/s) were selected to predict the formation behavior of Cr-rich precipitates (CrRP) under neutron irradiation conditions. The effects of Cr, Al composition, and dose rate on the CrRP formation behavior were evaluated using a three-dimensional atom probe (3DAP) analysis. The results showed that the CrRP number density, volume fraction, and Cr concentration increase with increasing Cr composition, decreasing Al composition, and decreasing dose rate. Multiple regression analysis showed that in addition to these primary effects, there was an interaction between them on the CrRP volume fraction: (1) the higher the Al composition, the smaller the increase in the CrRP volume fraction with increasing Cr composition, and (2) the lower the Cr composition, the smaller the increase in the CrRP volume fraction with the decreasing Al composition and dose rate. It was also highlighted that to understand the dose rate effect on the CrRP formation behavior under neutron irradiation, it is useful to examine the irradiation time dependence, including the effective use of thermal aging data as a limit to the zero dose rate, in addition to the dose-dependency perspective. In addition to the systematic database of CrRP-related quantities established in this study, these considerations should contribute to further developing and validating numerical prediction models.

A first step towards understanding thermomechanical behavior of the Nb-Cr system through interatomic potential development and molecular dynamics simulations

Utilizing a preliminary interatomic potential, this work represents an initial exploration into the thermomechanical behavior of NbCr solid solutions. Specifically, it examines the effect of different amounts of Cr solute, for which information in the literature is limited. The employed interatomic potential was developed according to the embedded atom model (EAM), and was trained on data derived from density functional theory calculations. While the potential demonstrated reasonable accuracy and predictive power when tested, various results highlight deficiencies and encourage further development and training. Mechanical strength, heat capacities, thermal expansion coefficients, and thermal conductivities were found to decrease with Cr content. Elastic coefficients, too, were observed to be strongly dependent on Cr composition. The Pugh embrittlement criterion was not satisfied for any of the compositions and temperatures explored. Gibbs free energy calculations performed on C14, C15, and C36 NbCr2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_{2}$$\\end{document} allotropes predicted the C36 structure to be the most thermodynamically favorable across all investigated temperatures and it was found that C36 becomes increasingly more stable relative to the other two phases with increased pressure. The inability of this work to accurately capture the stability of the different Laves phases is most likely due to the shortcomings in the developed potential.

Oxidative corrosion resistance of a CrxFeyNi1-x-y composition spread alloy film (CSAF) in dry air

Composition Spread Alloy Films (CSAFs) were used to study the resistance to oxidative corrosion of CrxFeyNi1-x-y alloys in dry air and determine the critical Cr composition, xCr∗, necessary to prevent bulk oxidation. CrxFeyNi1-x-y CSAFs were made using physical vapor deposition (PVD) and then oxidized in dry air between 100 – 500 °C for periods of 1 h. A sharp passivation boundary was observed at 300 °C separating alloys showing evidence of heavy oxidation from Cr-rich alloys that were passivated. X-ray photoelectron spectroscopy (XPS) depth profiling was used to measure the extent of oxidation and penetration depth of the oxide layer on either side of the passivation boundary. XPS measurements confirmed the presence of a critical Cr composition, xCr∗, ranging from 18 to 26 at.%. For alloys with xCr≥xCr∗, a sufficiently thick passivating layer of oxidized Cr, Cr(ox), had formed on the top surface preventing the oxidative corrosion of either Fe or Ni. On the other hand, when xCr<xCr∗, bulk oxidation was observed, with appreciable Fe(ox) and/or Ni(ox) measured on the surface and often penetrating through the entire alloy film thickness. The trajectory of xCr∗ plotted within CrxFeyNi1-x-y composition space supports the trend towards using higher Cr-content stainless steel grades in harsh oxidative environments.

A common isotopic reservoir for amoeboid olivine aggregates (AOAs) and calcium-aluminum-rich inclusions (CAIs) revealed by Ti and Cr isotopic compositions

Amoeboid olivine aggregates (AOAs) are the most abundant type of refractory inclusions found in most carbonaceous chondrite groups. AOAs are thought to be genetically related to calcium-aluminum-rich inclusions (CAIs) and potential chondrule precursor components, although the precise physical and temporal details of AOA formation and their relationship to other chondritic components remain unclear. In this study, we measured the chromium and titanium isotopic compositions of eight AOAs from four different CV chondrites with the goal of evaluating potential genetic links between AOAs, CAIs, and chondrules. These are the first Cr and Ti isotopic data reported beyond a single AOA previously measured for Cr and a different single AOA previously measured for Ti. The results presented here show that the ε54Cr and ε50Ti isotopic compositions of AOAs are indistinguishable from those of CAIs, suggesting that AOAs and CAIs formed from a common region of the disk. We also demonstrate, based on the comparison of the Cr and Ti isotopic composition of AOAs to previously measured chondrules, that mixing between AOAs and an NC compositional endmember alone cannot fully explain the range of measured chondrule compositions. Although AOAs may have been important chondrule precursor components along with AOA olivine, CAIs, fragments of earlier generation chondrules, and fine-grained matrix material, this observation requires another currently unknown component to be involved in chondrule formation.

Tellurium Corrosion of Type 304/304L Stainless Steel, Iron, Chromium, and Nickel in High-Temperature Liquid Sodium.

Investigating tellurium (Te) corrosion on structural materials is crucial for sodium-cooled fast reactors (SFRs) due to radionuclide presence and knowledge gaps. In this study, Type 304/304L stainless steel (SS304), chromium (Cr), iron (Fe), and nickel (Ni) samples were immersed in low-oxygen environments with Te in liquid sodium at 773 K for 30 days. At 10 ppm oxygen, SS304 showed multiple oxide layers, including a compact NaCrO2 interlayer and porous Na-Fe-Ni-O outer layers. Tellurium penetrated through the porous layers but was hindered by the NaCrO2 interlayer. At 0.01 ppm oxygen, Cr had no oxide layer, while Fe and Ni had unstable ones. Tellurium-induced pitting was deeper in Fe and Ni compared to Cr. Oxygen levels and Cr composition are critical factors affecting stable oxide compound layer formation and mitigating Te-induced pitting.

Accelerated corrosion of Ni-based alloys in molten chloride salts, due to Ni2Cr phase formation

To understand how the precipitation of long-range ordering (LRO) in alloys affects molten salt corrosion, two Ni-Cr model alloys—one in as-received (AR) condition, the other isothermally aged to contain MoPt2-type Ni2Cr-ordered precipitates, and both featuring the same Ni-33at%Cr composition—were tested for 500 hours in molten NaCl–MgCl2 salt at 550°C. Post-corrosion weight loss analysis and advanced microstructural characterization of the corroded alloys revealed (through comparison with the AR specimens) that the ordered phase significantly accelerated the corrosion process. This suggests that the loss of Cr atoms in the corroded Ni2Cr-ordered superlattice structure, which creates extra weakness for molten salt corrosion. In terms of high-temperature corrosion resistance, the results of this study emphasize the importance of phase stability when designing alloys for molten-salt applications.

Optimizing strength-corrosion properties in sulfuric acid environment via tailoring V–Cr composition in medium-entropy VCrCoNi alloys

The corrosion resistance of VCrCoNi medium-entropy alloys in a 0.5 M H2SO4 solution was investigated by tailoring V and Cr compositions while minimizing microstructural differences. The elemental effects were discussed regarding the formation of the passive film and its subsequent impact on corrosion resistance. The results revealed that an increase in the Cr/V ratio enhances the corrosion resistance by forming a Cr-enriched passive film. However, the elevated ratio negatively affects the mechanical strength, wherein V plays a crucial role. The optimal balance between mechanical strength and corrosion resistance was discussed based on electrochemical measurements and immersion test results.

Light stable Cr isotope compositions of mid-ocean ridge basalts: Implications for mantle source composition

Stable isotopes of chromium (Cr) and iron (Fe), both multivalent elements in silicate melts, are valuable proxies of redox conditions in magmatic systems. Partial melting and fractional crystallization have been identified as the dominant fractionation processes for Cr and Fe isotopes in high-temperature reservoirs that can lead to small but detectable isotope variations in igneous rocks. More recently, however, the source mineralogy has been suggested to play an important role, which can ultimately affect the magnitude of Cr and Fe isotopic fractionation during partial melting and thus the Cr and Fe isotopic composition of the originating melt.With the aim to investigate the role of magmatic processes and the source Cr and Fe isotope signatures on the isotope composition of these transition metals in normal mid-ocean ridge basalts (N-MORB), we analyzed 21 well-characterized MORB glasses from the southern East-Pacific Rise, Pacific-Antarctic Ridge and Mid-Atlantic Ridge. The Cr isotope compositions of N-MORB show a narrow range from −0.278 to −0.186 ‰ in δ53/52Cr (i.e., difference of a sample’s 53Cr/52Cr ratio relative to the international reference material NIST SRM979), with an average value of −0.237 ± 0.050 ‰ (2SD; n = 19). As such, the average N-MORB δ53/52Cr value is significantly lower than that of Bulk Silicate Earth of −0.12 ± 0.06 ‰ and the Cr isotope compositions reported for most ocean island basalts ranging from ∼ −0.23 to 0.00 ‰. Iron isotopic compositions of these MORB range from +0.032 to +0.137 ‰ in δ56/54Fe (i.e., difference of a sample’s 56Fe/54Fe ratio relative to the international reference material IRMM014) and are within the range of previously published MORB data. The lack of correlations between N-MORB Cr isotope signatures and indices of magmatic differentiation suggests a negligible control of this process on Cr stable isotopes. Partial melting modeling using pMELTS provides evidence that the significant offset towards lower δ53/52Cr values of N-MORB cannot be produced by decompression partial melting of a lherzolithic source such as the depleted upper mantle alone. Instead, we suggest that the lower δ53/52Cr values of MORB could be linked to intrinsic small-scale 53Cr-depleted pyroxene-rich domains in the upper mantle that influence the melt’s Cr isotopic budget during partial melting.

Screening of the FeCrAl LBE corrosion-resistant coatings: The effect of Cr and Al contents

Sixteen kinds of FeCrAl coatings with different Cr and Al contents were prepared by the magnetron sputtering method, and the thermal shock resistance and static lead‑bismuth eutectic (LBE) corrosion behavior (500– 650 °C for 1000 h) were investigated. The results show that the coating with poor thermal shock resistance could also peel off during the corrosion test, and the corrosion resistance of the coating is strongly related to the Cr and Al composition. A relatively high Al content could be required for the FeCrAl coatings to maintain outstanding performance, which is different from the traditional design of the FeCrAl bulk alloys.

Obtaining mechanically fused modifying ligatures with a high content of alloying component for the production of chrome bronzes

The paper presents the results of a study of the regularities of the formation of granulometric composition, structure and properties of modifying ligatures with a high content of alloying component for the production of chrome bronzes. The kinetics of changes in the physico‑mechanical properties of granular compositions depending on the temperature in the grinding chamber and the ratio of the volume of working bodies to the volume of the charge has been studied. The results of the topography of granules and their structure are presented, showing that the granules obtained according to the optimal mode of mechanical fusion are dense bodies with microinclusions of chromium, the maximum size of which does not exceed 15–20 microns.Based on the results of thermodynamic modeling, thermodynamically justified refractory compounds synthesized in the process of obtaining a ligature have been established, which should effectively perform the role of modifiers of the first kind, ensuring the production of bronzes with a sub‑/microcrystalline type of base structure.The processes of compacting mechanically fused compositions were optimized and the influence of the main technological factors – the heating temperature of cold‑pressed briquettes and the extraction coefficient during hot pressing on the physical and mechanical properties of compact materials was investigated. The results of studying the structure and properties of the most promising Cu – 20 %Cr composition are presented, which make it possible to identify its microcrystalline type, which persists after prolonged high‑temperature exposure during the processing of the granular composition into a semi‑finished product, and to conclude about the dispersed nature of its hardening, which additionally confi ms the data of thermodynamic modeling on the possibility of mechanical synthesis of nanocrystals of refractory compounds to perform the role of modifiers.According to the results of the research, a comparative analysis of the properties of the developed ligature and beryllium bronze was performed, establishing the possibility of its use as an independent material for electrical purposes.

Influence of Cr-content on the local atomic structure of Fe–Cr alloy, a study using EXAFS

High Cr ferritic/martensitic steels are considered one of the most promising structural materials for advanced nuclear power plants. Therefore, understanding properties' evolution under operation conditions is of primary importance. Neutron scattering data and more recent ab initio calculations reveal that magnetism controls the transition from the local short-range ordering of the Cr clustering inside the alloy. The transition coincides with the change in the alloy heat of formation, which shifts from a small area with negative values to a region of positive values at around 10% Cr. This work aims to investigate the effect of Cr composition on the local atomic environment of Fe–Cr alloys. This work employed EXAFS to probe the local environment of Fe–Cr alloys as a function of Cr composition. The results show the anomaly (softening) of the nearest neighbor distance around Cr atom in the 10%Cr. Furthermore, the local atomic disorder around Cr absorbing atoms is larger than Fe atoms.

LHAASO on Cosmic Ray Knees

LHAASO construction was complete in July 2021. The full array is operating very stably since then. All arrays, KM2A, WCDA and WFCTA are calibrated, including the absolute energy scale at 21 TeV, which was measured by using WCDA and propagated to WFCTA, with the uncertainty will be reduced down &lt;10% in 4 years. The knee of pure proton spectrum will be measured in the first phase of the hybrid measurements of showers using four types of EAS detection techniques started in 2019 winter. Sufficient data have been collected and the analysis is in progress. Since the last run, the second phase were started in 2021 winter. The knee of the iron spectrum is the goal which will take at least 3 years of data collection. CR all-particle spectrum, composition and anisotropy are under analysis.

Environmental Risk from Organic Residues

Soil nutrient imbalance is a global threat to food security and ecosystem sustainability but adding organic residues or constructing anthropogenic soils and technosols can optimize it. However, FAO considers organic residues not “risk-free”, mainly due to their heavy metal content. Despite the fact that applying pruning residues to soil is a worldwide fertilization practice, its potential heavy metal risk has been poorly studied. This work characterizes Cu, Zn, Cd, Cr, Ni and Pb elemental composition concentration and their solubility content in almond tree pruning, commercial peat substrate, hay straw, olive tree pruning, pomegranate peel, pine needle, date palm leaf pruning, sewage sludge compost and vine pruning. Furthermore, we compare the legal frameworks governing heavy metal content in agricultural substrates to heavy metal concentration in each residue. Results show that commercial peat substrate is the only one among those studied that surpasses the threshold value for Cr in agricultural substrates. All pruning residues met the heavy metal threshold value; hence, their application to soil involves minimal soil toxicity. Moreover, the solubility index of heavy metals and the maximum quantity of each residue are crucial to discerning a heavy metal-free organic fertilization plan.

Nano-twinning induced high strain hardening behavior in a metastable as-cast Co30Cr30Fe20Ni20 high entropy alloy at room temperature

High entropy alloys (HEAs) utilize multiple deformation mechanisms to overcome the strength-ductility trade-off by deformation treatment and low temperature conditions. To develop original engineering materials with strength-ductility synergy properties, we induced multiple deformation strengthening mechanisms into the as-cast face-centered cubic (FCC) HEAs at room temperature. A metastable as-cast Co 30 Cr 30 Fe 20 Ni 20 HEA was designed by adjusting composition and prepared by melting. The tensile properties and deformation microstructure evolution were investigated. Co 30 Cr 30 Fe 20 Ni 20 HEA has larger lattice distortion, stronger atomic binding force, and lower stacking fault energy (SFE) than equiatomic CoCrFeNi HEA. The low SFE and large grain size promote multiple slip systems (single slip, crossing slip, and blocked slip) activation and the formation of deformation twins. The as-cast Co 30 Cr 30 Fe 20 Ni 20 shows excellent properties at room temperature, including yield strength of 267 MPa, tensile strength of 613 MPa, and fracture strain of 96.2%, which increases by 92.2%, 47.9%, and 10.50% than that of equiatomic CoCrFeNi HEA. The enhancement of yield strength results from solid solution strengthening and strong atomic binding forces. The tensile strength-ductility synergy is attributed to a high strain hardening rate by utilizing multiple slip interactions of dislocations and twinning-induced plasticity (TWIP). • A metastable as-cast Co 30 Cr 30 Fe 20 Ni 20 HEA was designed by adjusting Co and Cr composition. • Co 30 Cr 30 Fe 20 Ni 20 HEA has large lattice distortion, strong atomic binding force, and low stacking fault energy. • As-cast Co 30 Cr 30 Fe 20 Ni 20 shows excellent strength-ductility synergy at room temperature, including tensile strength of 613 MPa and elongation of 96.2%. • Properties improvement is attributed to high strain hardening rate by utilizing multiple slip interactions of dislocations and twinning-induced plasticity.

Feasibility of 24-h urine creatinine clearance as a renal function monitoring tool in spinal cord injury patients.

Renal dysfunction is a major cause of morbidity in patients with spinal cord injury (SCI). A 24-h urine creatinine (Cr) clearance (24-h urine CCr) is cost-effective and easy to implement compared to renal scintigraphy in the evaluation of renal function. This study aimed to verify the feasibility of 24-h urine CCr in the SCI population by assessing the correlation with effective renal plasma flow (ERPF) on renal scintigraphy. Data from 245 SCI patients (189 males, mean age: 50.2 years) were used in this retrospective review. Clinical characteristics, 24-h urine CCr, serum Cr, comorbidities, and body composition analyses were assessed for correlation with laboratory parameters including renal scintigraphy. Strong predictors of ERPF were determined by multivariate linear regression analysis. Areas under receiver-operating characteristic curves were calculated to evaluate the discriminating power of 24-h urine CCr to predict ERPF <250 ml/min. Spinal cord injury patients showed tubular dysfunction despite normal serum Cr and 24-h urine CCr. There was a significant correlation between 24-h urine CCr and ERPF, and 24-h urine CCr was one of the strongest predictors for ERPF (area under the curve 0.72, 95% CI 0.64-0.80, p < 0.000) among other parameters such as age, appendicular lean mass index, and body mass index. 24-h urine CCr was an independent predictor of ERPF in subacute (R2 = 0.497, p < 0.001) and chronic SCI patients (R2 = 0.664, p < 0.0001). The optimized 24-h urine CCr cut-off was 139.4 ml/min/1.72 m2 for predicting decreased ERPF <250 ml/min (sensitivity 67.6% and specificity 64.0%). 24-h urine CCr is a sensitive indicator for renal function deterioration of SCI patients. Further longitudinal studies with larger numbers of SCI patients are needed to confirm the feasibility of 24-h urine CCr for monitoring this population.

Influence of substitution of different transition metal elements (Mn, Cr, Co) on the properties of Bi0.88Sm0.12FeO3-based ceramics

In this paper, the transition metal elements modified Bi0.88Sm0.12Fe0.97M0.03O3 (M = Mn, Cr, Co, Mn0.5Cr0.5, Mn0.5Co0.5, Cr0.5Co0.5) ceramics were synthesized by rapid liquid phase sintering. The effect of different transition metal elements on the structure and characteristics of BiFeO3-based ceramic were studied. Structural refinement revealed the coexistence of rhombohedral R3c phase, orthorhombic Pna21 phase and a small amount of Pbnm phase of all samples, and the element type had little effect on the phase composition. According to the XPS analysis, Co and Mn elements can be regarded as hard additives, and Cr element can be regarded as soft additives. Due to the different electronic structures of transition metal elements, different element substitutions have different effects on the electrical and magnetic properties of BiFeO3. The results show that the addition of Cr improved the electrical properties of BSF-based ceramics, and the best ferroelectric properties obtained in the BSF-Cr sample, where Pr = 18.30 μC/cm2. The magnetic properties of Co substituted samples were significantly improved, and the maximum remanent magnetization obtained in the BSF-Co sample, where Mr = 110.8 emu/mol, which may be attributed to the collinear magnetic structure induced by Co-substitution. Finally, the simultaneously enhanced ferroelectric and magnetic properties were obtained in the Cr and Co co-substituted composition, where Pr = 10.82 μC/cm2, Mr = 73.3 emu/mol. Multiple ion substitution is a very effective method to optimize the properties of BiFeO3.

First-principles investigation of the role of Cr in the electronic properties of the two-dimensional MoxCr1−xSe2 and WxCr1−xSe2 alloys

The tuning of the structural and electronic properties of two-dimensional semiconductor monolayers is highly desirable for designing van der Waals heterostructures, which can be employed for several optoelectronic applications. Here, we report a theoretical investigation based on the combination of spin-polarized density functional theory calculations and alloying structures generated by the special quasirandom structure method to investigate the energetic stability and band gap engineering of the compounds ${\mathrm{Mo}}_{x}{\mathrm{Cr}}_{1\ensuremath{-}x}{\mathrm{Se}}_{2}$ and ${\mathrm{W}}_{x}{\mathrm{Cr}}_{1\ensuremath{-}x}{\mathrm{Se}}_{2}$ as a function of the Cr composition for $x=0$ up to 1. We found that even a small concentration of Cr already flattens the low-energy electronic bands and decreases the fundamental electronic band gap. Due the lattice mismatch of the compounds ${\mathrm{CrSe}}_{2}$ and Mo(W)${\mathrm{Se}}_{2}$, the renormalization of the electronic properties is nonlinear as a function of the Cr composition. We found bowing parameters for the work function and band gap that change in magnitude from 0.066 to $1.178\phantom{\rule{0.16em}{0ex}}\mathrm{e}\mathrm{V}$, respectively. From our analyses, Cr alloying decreases the band gap of these monolayers in the direction of the maximum performance band gap predicted by the Shockley-Queisser limit for photovoltaic applications. Band alignment analysis reveals that stacks of Mo(W)${}_{x}{\mathrm{Cr}}_{1\ensuremath{-}x}{\mathrm{Se}}_{2}$ monolayers with particular compositions $x$ can form type II heterojunctions with a high solar harvesting efficiency.

Heats of formation and stress–strain relationship of Fe–Cr solid solutions from a constructed Fe–Cr potential

A new Fe–Cr interatomic potential is constructed under the framework of the embedded-atom method and has better performances in predicting heats of formation and stress–strain relationship of Fe–Cr solid solutions than the Fe–Cr potentials already published in the literature. Based on the constructed Fe–Cr potential, molecular dynamics simulation reveals that the heats of formation of BCC Fe–Cr solid solutions at 1600 K are positive within the entire composition range, and the calculated values are in good agreement with corresponding experimental measurements in the literature. In addition, it is also found that the tensile strengths of BCC Fe–Cr solid solutions increase with the increase of the Cr composition, and that BCC Fe–Cr solid solutions are less ductile with smaller critical strains than both Fe and Cr. The simulated results are discussed and compared with the corresponding experimental and calculated evidence in the literature to validate the relevance of the newly constructed Fe–Cr potential.