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Mars experienced a dynamo process that generated a global magnetic field ~4.3 (or earlier) to 3.6 billion years ago (Ga). The cessation of this dynamo strongly affected Mars' history and is expected to be linked to thermochemical evolution of Mars' iron-rich liquid core, which is strongly influenced by its thermal conductivity. Here, we directly measured thermal conductivities of solid iron-sulfur alloys to pressures relevant to the Martian core and temperatures to 1023 Kelvin. Our results show that a Martian core with 16 weight % sulfur has a thermal conductivity of ~19 to 32 Watt meter-1 Kelvin-1 from its top to the center, much higher than previously inferred from electrical resistivity measurements. Our modeled thermal conductivity profile throughout the Martian deep-mantle and core indicates a ~4-to 6-fold discontinuity across the core-mantle boundary. The core's efficient cooling resulting from the depth-dependent, high conductivity diminishes thermal convection and forms thermal stratification, substantially contributing to cessation of Martian dynamo. [ABSTRACT FROM AUTHOR]

The application of compost to agricultural soils can increase nutrient leaching, causing several environmental problems. Conversely, proper management of compost application can reduce environmental risks. Agronomical trials were conducted in greenhouses in Morocco to compare the effects of varying compost application rates, types, and maturity, as well as the number of growing days, on nutrient availability and nitrate leaching in a loamy sandy soil. Additionally, the study examined the impacts of these factors on soil physical and chemical characteristics. The compost used in this study was derived from a combination of two cost-effective materials, municipal waste, and poultry manure. Tomato plants were cultivated in pots amended with compost over a period of 65 days. The soils were treated with eight composts (plus a control) obtained from municipal solid waste (MSW) mixed with poultry manure (PM) at two ratios, 3:2 and 2:3 weight weight−1 (ww−1) (C1 and C2, respectively), used at two different ages (105 days and 173 days) and at two doses (32.5 g pot−1 and 65 g pot−1, equivalent to 40 Mg ha−1 and 80 Mg ha−1). Two simulated leaching events (the first after planting and the second at harvest) were performed. The concentration of chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN) in leachate varied with the number of growing days and increased in the leachate of the non-amended soil after planting. At both sampling times, compost C1, aged 173 days (d), significantly decreased COD in the leachate compared to compost C1 aged 105 d. Compost increased nitrate leaching compared with the non-amended soil. Nitrogen leaching was primarily in the form of nitrate, ranging from 61% to 78% over the whole experimental period. Compost also decreased leachate concentrations of iron (Fe) and chromium (Cr), for other metals, such as cobalt (Co) and nickel (Ni), values were very low. Moreover, compost increased total organic carbon by up to twofold at both sampling times, with the most substantial increase observed with a dose of 65 g pot−1 of compost C2 (aged 105 days). Most compost treatments also increased available phosphorus (P), inorganic nitrogen (N), total nitrogen (TNK), cation exchange capacity (CEC), and electrical conductivity (EC) at both sampling times but had no effect on pH. The metal content in the soil exhibited a decrease compared to the control soil. Overall, our study suggests that nitrogen leaching can be reduced by optimizing compost rates, properties, and stability to synchronize with crop needs. [ABSTRACT FROM AUTHOR]

Recently, perovskite (ABO3) nanomaterials have been widely explored as a class of versatile electrocatalysts for oxygen evolution reactions (OER) due to their remarkable compositional flexibility and structural tunability, but their poor electrical conductivity hinders hydrogen evolution reaction (HER) activity and further limits the large-scale application of perovskite oxide in overall water splitting (OWS). In this study, hollow-nanotube-structure LaxCo0.4Fe0.6O3−δ (x = 1.0, 0.9, and 0.8) perovskites with superior HER/OER activity were synthesized on nickel-iron alloy foam (denoted LaxCoFe/NFF) using hydrothermal with a subsequent calcination strategy. Among them, La0.9CoFe/NFF not only exhibited extraordinary HER electrocatalytic performance (160.5 mV@10 mA cm−2 and 241.0 mV@100 mA cm−2) and stability (20 h@10 mA cm−2), but also displayed significant OER electrocatalytic activity (234.7 mV@10 mA cm−2 and 296.1 mV@100 mA cm−2) and durability (20 h@10 mA cm−2), outperforming many recently reported HER/OER perovskite catalysts. The increase in oxygen vacancies caused by the introduction of La deficiency leads to the expansion of the lattice, which greatly accelerates the HER/OER process of La0.9CoFe/NFF. Additionally, the naturally porous skeleton can prevent catalysts from aggregating as well as delay the corrosion and dissolution of catalysts in the electrolyte under high applied potentials. Furthermore, the assembled two-electrode configuration, utilizing La0.9CoFe/NFF (cathode and anode) electrodes, only requires a low cell voltage of 1.573 V at 10 mA cm−2 for robust alkaline OWS, accompanied by remarkable durability over 20 h. This work provides inspiration for the design and preparation of high-performance and stable bifunctional perovskite electrocatalysts for OWS. [ABSTRACT FROM AUTHOR]

A big amount of vanadium is used in the industry. It is used as a vanadium carbide stabiliser in steel production. Only $ 0.5\% $ 0.5 % vanadium in an iron alloy will double the tensile strength. Vanadium salts are used in leather, ink, dye manufacturing and yellow ceramic glaze. On the other hand, vanadium pentoxide is used as a catalyst, in the chemical industry, for the production of sulphuric acid and in the petroleum refinery industry. Resolvability parameter is the most discussed topic in graph theory. This helps to reorganise a network in a unique way, sometimes in terms of atoms (metric dimension) and sometimes bound (edge metric dimension). We studied resolvability parameters of vanadium carbide network in this article i.e. metric, edge metric and partition dimension. Among these metrics resolvability defined by parameters taking a subset from the set of vertices, if it has a unique representation with all the vertices, then it is called a resolving set. The number of elements in the smallest resolving set is called the metric dimension. While the number of elements of the minimal subset of vertices taking from vertex set is called the edge metric dimension, if the representations are unique of all edges and the set is called the edge resolving set. This study can have an effect in many ways in the research, particularly, with the help of some key points such as network structure analysis, material science via material properties, graph theory applications, predictive modelling, material testing and characterisation, as well as in industrial applications. [ABSTRACT FROM AUTHOR]

The optical intersite spin transfer (OISTR) effect was recently verified in Fe50Ni50 using extreme ultraviolet magneto-optical Kerr measurements. However, one of the main experimental signatures analyzed in this work, namely a magnetic moment increase at a specific energy in Ni, was subsequently found also in pure Ni, where no transfer from one element to another is possible. Hence, it is a much-discussed issue whether OISTR in FeNi alloys is real and whether it can be verified experimentally or not. Here, we present a comparative study of spin transfer in Fe50Ni50, Fe19Ni81 and pure Ni. We conclusively show that an increase in the magneto-optical signal is indeed insufficient to verify OISTR. However, we also show how an extended data analysis overcomes this problem and allows to unambiguously identify spin transfer effects. Concomitantly, our work solves the long-standing riddle about the origin of delayed demagnetization behavior of Ni in FeNi alloys. Optical intersite spin transfer (OISTR), which is driven by an ultrafast optical excitation, was recently found in several materials, but there is some disagreement over how this phenomenon can be observed experimentally. Here, the authors investigate the mechanism of intersite spin transfer in a set of FeNi alloys and make a comparison with pure Ni, demonstrating and discussing the challenges of observing OISTR using magneto-optical measurements. [ABSTRACT FROM AUTHOR]

In this paper the influence introducing various plasticizers into an initial charge on the structure and properties of iron-based powder materials alloyed with copper is considered. It is shown that introduction of copper stearate into an initial powder mixture and warm mixing, pressing and subsequent sintering makes it possible to obtain low-porosity workpieces with relative porosity of 95%. Pores within the workpieces obtained have a small size of 10–15 microns and a rounded shape. Also, bending strength is determined for sintered samples of all the compositions of powder mixtures studied and the Rockwell hardness is determined on the C scale. Powder steels based upon mixtures have the best set of mechanical properties PZhRV 2.200.28 + 0.7 wt.% Br + 0.7 wt.% Cu + 1 wt. % StCu + warm mixing—hardness HRC 58. flexural strength 600 MPa PZhRV 2.200.28 + 1.4 wt.% Br + 1.4 wt.% Cu + 1.4 wt.% C + 1.0 wt.% StFe + warm mixing—hardness HRC 100, flexural strength 530 MPa [ABSTRACT FROM AUTHOR]

Most common ferroalloys are produced mainly by carbothermal reduction of high-grade ores or concentrates, which results in large CO2 emissions. Hydrogen is a promising alternative to coke and coal, which are reducing agents in the carbothermal process. Hydrogen production is becoming increasingly cheaper, and in the future, it may become available for extensive industrial applications. The advantage of using hydrogen is due to its ability to reduce many different oxides, which are the sources of metals in ferroalloy production, at lower temperatures than using carbon-based reducing agents. Hydrogen is the most promising, and its use is presently possible in the production of ferrotungsten, ferromolybdenum, and ferronickel. [ABSTRACT FROM AUTHOR]

Explaining the crystallography of iron alloys martensite with a {225}γ habit plane remains a challenging task within the phenomenological theory of martensite crystallography. The purpose of this study is to re-examine the martensite formed in a Fe-8Cr-1.1C alloy using EBSD, which has a better angular resolution than the conventional transmission electron diffraction techniques previously used. The results show that the single morphological plates, which hold a near {225}γ habit plane, are bivariant composites made up of two twin-related variants. It is shown that a {113}γ plane is systematically parallel to one of the three common 112 α planes between the two twin-related crystals. This observation suggests that the lattice invariant strain of transformation occurs through a dislocation glide on the {113}γ 〈110〉γ system, rather than through twinning as is commonly accepted. Based on this assumption, the predictions of Bowles and Mackenzie's original theory are in good agreement with the crystallographic features of {225}γ martensite. Unexpectedly, it is the high shear solution of the theory that gives the most accurate experimental predictions. [ABSTRACT FROM AUTHOR]

Nanocrystalline metals have many applications in nanodevices, especially nanoscale electronics in aerospace. Their ability to resist fracture under impact produced by environmental stress is the main concern of nanodevice design. By carrying out molecular dynamics simulations under different fast loading rates, this work examines the effect of impact load on the fracture behavior of nanocrystalline bcc iron at an atomistic scale. The results show that a crack propagates with intergranular decohesion in nanocrystalline iron. With the increase in impact load, intergranular decohesion weakens, and plastic behaviors are generated by grain boundary activities. Also, the mechanism dominating plastic deformation changes from the atomic slip at the crack tip to obvious grain boundary activities. The grain boundary activities produced by the increase in impact load lead to an increase in the threshold energy for crack cleavage and enhance nanocrystalline bcc iron resistance to fracture. Nanocrystalline bcc iron can keep a high fracture ductility under a large impact load. [ABSTRACT FROM AUTHOR]

The microstructure of the in situ TiC-reinforced composite surface layers developed during laser surface alloying of a ductile cast iron substrate with titanium was related to the solidification conditions in the molten pool. The solidification conditions were estimated using infrared thermography. It was found that the cooling rates of the melt up to about 700 °C/s enable the complete reaction between carbon and the entire amount of titanium introduced into the molten pool. In turn, the cooling rate of about 280 °C/s for the melt containing 8.0 wt% Ti allows the TiC particles to grow in the dendritic form with well-developed secondary arms and a total size of up to 30 µm. For a constant Ti content, the cooling rate of the melt had no effect on the TiC fraction. The increase in the cooling rate elevated the retained austenite fraction in the matrix material, lowering its hardness. [ABSTRACT FROM AUTHOR]

In view of the complex structure and insoluble problems of platinum-containing group metal ferroalloys, alkali roasting desiliconization pretreatment was carried out to destroy stab! and dense alloy structures. The experimental results show that the optimum roasting conditions are as follows: mass ratio of alkali to material 1. 4, roasting temperature 600 °C, roasting time 2. 0 h, under these conditions, the alloy phase is completely decomposed into NaFeO2 and Na4SiO4 'Na4SiO4 is removed via water leaching and the silicon content in the obtained water leaching residue is reduced to 0. 84%. After desiliconization, the material has loose structure' high activity, and is easy to remove iron via add dissolution, which is conducive to the refining and recovery of platinum group metals. [ABSTRACT FROM AUTHOR]

Heavy metals from mica waste not only deteriorate the soil quality but also results in the uptake of metals in the crop. The present investigation was conducted to evaluate the effects of different fractions of metals on the uptake in rice, soil microbial and biochemical properties in mica waste-contaminated soils of Jharkhand, India. From each active mine, soil samples were randomly collected at distances of < 50 m (zone 1), 50–100 m (zone 2), and >100 m (zone 3). Sequential metal extraction was used to determine the fractions of different metals (nickel (Ni), cadmium (Cd), chromium (Cr) and lead (Pb)) including water-soluble (Ws) and exchangeable metals (Ex), carbonate-bound metals (CBD), Fe/Mn oxide (OXD) bound metals, organically bound metals (ORG), and residues (RS). The Ni, Cr, Cd and Pb in rice grain were 0.83±0.41, 0.41±0.19, 0.21±0.14 and 0.17±0.08 mg/kg respectively. From the variable importance plot of the random forest (RF) algorithm, the Ws fraction of Ni, Cr and Cd and Ex fraction of Pb was the most important predictor for rice grain metal content. Further, the partial dependence plots (PDP) give us an insight into the role of the two most important metal fractions on rice grain metal content. The microbial and enzyme activity was significantly and negatively correlated with Ws and Ex metal fractions, indicating that water-soluble and exchangeable fractions exert a strong inhibitory effect on the soil microbiological parameters and enzyme activities. [Display omitted] [ABSTRACT FROM AUTHOR]

To explore the crystalline arrangement of the alloy and the processes involving iron (Fe) precipitation, we employed molecular dynamics simulation with a cooling rate of 2 × 1010 for Cu100-XFeX (where X represents 1%, 3%, 5%, and 10%) alloy. The results reveal that when the Fe content was 1%, Fe atoms consistently remained uniformly distributed as the temperature of the alloy decreased. Further, there was no Fe atom aggregation phenomenon. The crystal structure was identified as an FCC-based Cu crystal, and Fe atoms existed in the matrix in solid solution form. When the Fe content was 3%, Fe atoms tended to aggregate with the decreasing temperature of the alloy. Moreover, the proportion of BCC crystal structure exhibited no obvious changes, and the crystal structure remained FCC-based Cu crystal. When the Fe content was between 5% and 10%, the Fe atoms exhibited obvious aggregation with the decreasing temperature of the alloy. At the same time, the aggregation phenomenon was found to be more significant with a higher Fe content. Fe atom precipitation behaviour can be delineated into three distinct stages. The initial stage involves the gradual accumulation of Fe clusters, characterised by a progressively stable cluster size. This phenomenon arises due to the interplay between atomic attraction and the thermal motion of Fe-Fe atoms. In the second stage, small Fe clusters undergo amalgamation and growth. This growth is facilitated by non-diffusive local structural rearrangements of atoms within the alloy. The third and final stage represents a phase of equilibrium where both the size and quantity of Fe clusters remain essentially constant following the crystallisation of the alloy. [ABSTRACT FROM AUTHOR]

2,5-Bis(4-dimethylaminophenyl)-1,3,4-oxadiazole (DAPO), 2-acetylthiophene thiosemicarbazone (2-AT), 2-hydroxyphenyl-5-mercapto-1-oxa-3,4-diazole (HMO), and 2-cinnamyl-5-mercapto-1-oxa-3,4-diazole (CMO) have been studied by measurement several quantum chemical parameters such as EHOMO, ELUMO, bandgap energy, softness, hardness, electrophilicity, nucleophilicity, and Fukui function analysis. The best corrosion inhibition efficiency was evaluated through a comparison between theoretical and experimental results. In gas and aqueous phases, protonated and nonprotonated species were investigated for their electronic structures in order to discover the factors and reasons behind corrosion inhibition. A theoretical study of all the studied compounds in gas and aqueous phases was investigated by employing the density functional theory (DFT) at 6–311++G(d, p) basis set and Becke's three parameters hybrid exchange–correlation functional (B3LYP). The molecules are calculated using quantum computational chemistry calculations such as Gaussian09 software. The experiments were carried out on carbon steel and HCL. Carbon steel is the most often used steel because it combines outstanding mechanical qualities with a low cost. One of the most commonly utilized agents for these purposes is HCl solution. On the other hand, steel and ferrous alloys are likely to corrode under certain conditions. One of the most effective strategies for protecting metals against corrosion is corrosion inhibitors, and they are becoming more common. [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopy (XPS) results from a set of experimental grade oxidized, iron based alloys of varying compositions, and oxidization levels and having different crystalline phases and structures are compared and correlated. It is shown how their binding energy profile-contours can vary from alloy to alloy for the same elements which are present in different proportions under varying preparation conditions. Such XPS analysis was more successful for cross-checking composition w.r.t. other analytical techniques like Energy dispersive X-ray analysis (EDAX) or X-ray fluorescence methods (XRF). Changes in crystallinity, composition, sample preparation conditions, oxidation and related phase changes contributed significantly to observed chemical changes in these alloy samples. In non-electronic grade materials, observing unexpected impurities can be common. So, such XPS analysis helps estimate the likely performance of an alloy and also detects the extent of unwanted impurities at the preparation stage itself that may affect the performance. [ABSTRACT FROM AUTHOR]

For Al-Mg-Si alloys, cooling after homogenisation is a crucial step because the precipitation of the equilibrium β-Mg2Si phase determines the processing capabilities in subsequent steps, as well as the subsequent precipitation age hardening potential, and thus, the final properties. It is therefore important to understand how microstructural variations affect the transformation of β-Mg2Si during cooling after homogenisation. In the present work, alloys with similar effective solute contents of Mg and Si, but with different microstructures and a different amount of primary Al-Fe-Si phases, were produced. Characterisation of the precipitation reaction was performed using interrupted quench experiments with cooling rates of 1–6 K/min, monitored by light optical microscopy (LOM), scanning electron microscopy (SEM) and conductivity measurements. Precipitation kinetics for β-Mg2Si was found to increase in microstructures with shorter secondary dendrite arm spacing (DAS). However, despite measuring both a higher density and volume fraction of the primary phases, no effect on the phase transformation from an increased iron content was found in terms of precipitation kinetics or particle count statistics. Furthermore, comparisons with iron-free high-purity-based alloys revealed that the precipitation reaction for β-Mg2Si was identical in the two different microstructures both in terms of onset temperature and overall kinetics. The present results show that nucleation of β-Mg2Si is not dependent on the larger constituent phases and indicates that overall transformation kinetics is governed by bulk diffusion rates. [ABSTRACT FROM AUTHOR]

Titanium oxide is a major component of bauxite residue (BR) with a high value, but it is often an unwanted element in common BR reuse options such as cement or iron production. Conventional carbothermic reduction smelting of BR produces a slag still containing a large amount of Ti. This study investigates an aluminothermic process for producing an FeTi alloy by combining BR, ilmenite ore, and fluxes. Based on thermodynamic calculations and batch experiments, the amounts of aluminum (reductant) and fluxes were investigated to achieve the optimum alloy production in parallel with a slag that could be further valorized in the cement industry. The mineralogical and chemical analysis of the metallic and slag phase agreed with the thermodynamic calculations. The results obtained by this study can lead to the development of a new process for the complete valorization of BR, paving the way for scaling up aluminothermic processes for producing ferroalloys from all iron-rich residues. [ABSTRACT FROM AUTHOR]

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As a promising candidate for accident-tolerant fuel (ATF) cladding materials, FeCrAl alloys are susceptible to hydrogen embrittlement (HE) under high-temperature radioactive water environments. Understanding the HE mechanism of FeCrAl is crucial, and studying H 2 dissociative adsorption can provide valuable insights since it is the first step in the HE processes. In this paper, we investigated the H 2 dissociative adsorption on Fe (110) and FeCrAl (110) surfaces using first-principles calculations based on Density Functional Theory (DFT). Our results indicate that the decomposition of H 2 molecules on FeCrAl (110) surfaces is significantly affected by surface elemental effects compared to Fe (110) surfaces. Specifically, Al atoms weaken both the H 2 decomposition and the H binding strength of Al-containing sites. Cr atoms decrease the decomposition tendency of H 2 in certain configurations, but Cr aggregation enhances the binding strength of H atoms on Cr-containing sites. The mechanism underlying the Al/Cr weakening effects on H 2 decomposition is due to the charge deficiency through alloying. Our findings have generalized implications for studying the interactions between iron-based alloys and hydrogen in various applications such as hydrogen storage, transportation, and prevention. • The strength of H 2 –Fe/Cr/Al interactions follow the order: H 2 –Al < H 2 –Cr < H 2 –Fe. • Al atoms have strong weakening effect on H 2 dissociation compared to Fe. • Cr atoms have slight weakening effect on H 2 dissociation compared to Fe. • The Cr aggregation can enhance H 2 –Cr interaction & H binding strength. • The weakening effects of Al & Cr on H 2 dissociation are caused by the charge deficit of Al & Cr after alloying with Fe. [ABSTRACT FROM AUTHOR]

The emergence of defects during the early production phases of ferrous-alloy additively manufactured (AM) parts poses a serious threat to their versatility and adversely impacts their overall mechanical performance in industries ranging from aerospace engineering to medicine. Lack of fusion and gas entrapment during the manufacturing stages leads to increased surface roughness and porosities in the finished part. In this study, the efficacy of employing electroless nickel–boron (Ni-B) deposition to fill and level simulated AM defects was evaluated. The approach to levelling was inspired by the electrochemical deposition techniques used to fill vias in the electronics industry that (to some extent) resemble the size and shape of AM-type defects. This work investigated the use of surfactants to attenuate surface roughness in electroless nickel coatings, thereby achieving the preferential inhibition of the coating thickness on the surface and promoting the filling of the simulated defects. A cationic surfactant molecule, CTAB (cetyltrimethyl ammonium bromide), and a nonpolar surfactant, PEG (polyethylene glycol), at different concentrations were tested using a Ni-B electrolyte for the levelling study. It was found that the use of electroless Ni-B to fill simulated defects on ferrous alloys was strongly influenced by the concentration and nature of the surfactant. The highest levelling percentages were obtained for the heavy-molecular-weight PEG-mediated coatings at 1.2 g/L. The results suggest that electroless Ni-B deposition could be a novel and facile approach to filling defects in ferrous-based AM parts. [ABSTRACT FROM AUTHOR]

The influence of Na 2 MoO 4 concentration on the electrochemical deposition of Co–Fe and Co–Fe–Mo alloy coatings from slightly acidic citrate baths and their electrocatalytic performance for alkaline water electrolysis in 1 M NaOH solution have been examined. The chemical composition and the evolution of the crystallographic structure have been analyzed by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), and scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) measurements. Increasing concentration of Mo in the alloy led to gradual amorphization of the crystalline structure. Electrochemical studies revealed that the cathodic Tafel slope reduced to 69 mV/dec for Co–Fe–Mo alloys. Furthermore, a low overpotential value of −121 mV was observed from polarization studies, which confirmed a good catalytic activity for the alkaline water splitting process. • Co–Fe and as Co–Fe–Mo ternary alloys, were fabricated on a copper electrode at different conditions. • Addition of Mo into alloy led to amorphization of the crystalline structure and decrease the overpotential value. • The enhanced activity of Co 57 Fe 24 Mo 19 ternary alloy is related to the synergetic effects between elements. [ABSTRACT FROM AUTHOR]

Interaction between hydrogen atoms and dislocations is studied in the iron-, nickel-, and titanium-based alloys using ab initio calculations and experimental studies of the electron structure, as well as mechanical spectroscopy. It is obtained that hydrogen increases the density of electron states, DOS, at the Fermi level, which is responsible for the increased concentration of free electrons decreasing thereby the elasticity moduli, and results in the decreased line tension of dislocations causing their increased mobility. By means of mechanical spectroscopy, the hydrogen diffusion enthalpy, ΔH d , and that of binding between hydrogen atoms and dislocations, ΔH b , have been measured. It is shown that these values control temperature T c for condensation of hydrogen atoms at dislocations. Consequently, in a definite range of temperatures and strain rates, dislocations move accompanied by hydrogen atmospheres, which is a reason for hydrogen embrittlement. Hydrogen embrittlement in the iron-, nickel- and titaniun-based alloys is analyzed in terms of this concept. Based on the obtained results, the use of hydrogen as a temporary alloying element increasing techological plasticity of β titanium alloys is interpreted. [Display omitted] •Joint hydrogen-dislocation slip is a precondition for embrittlement. •Temperature range of HE is controlled by H diffusion and binding to dislocations. •Hydrogen enhances plasticity in the absence of hydrogen dislocation atmospheres. [ABSTRACT FROM AUTHOR]

The total reorganization energy of the system and its components, the solvent reorganization energy and the transformation energy of reactants (water clusters [(H2O)nOH]-), during electrocatalytic hydrogen evolution on binary alloys of molybdenum with iron subgroup metals (Fe, Co, Ni) in an alkaline medium (30 wt.% NaOH solution) have been calculated. The calculated values of the solvent reorganization energy and the reorganization energy of water clusters are in agreement with the Marcus - Dogonadze - Kuznetsov theory. The dependence of the total reorganization energy of the system, the solvent reorganization energy, and the reorganization energy of discharging species (water clusters) on the electrolyte temperature has been calculated. It was shown that the total reorganization energy of the system and the activation energy of the electron-transfer reaction of electrocatalytic hydrogen evolution (HER) on binary alloys of molybdenum with iron subgroup metals in an alcaline vedium (30 wt.% NaOH solution) decrease linearly with increasing electrolyte temperature in the following order: Fe-54 at. % Mo > Ni-54 at. % Mo > Co-52 at. % Mo. The temperature dependences of the water cluster discharge reorganization energy and the activation energy on binary molybdenum alloys are linear and intersect in the boiling point region of 30 wt.% NaOH solution 384.7 K. At this temperature, the electrode process is limited by the diffusion of regenerating water clusters to the electrode surface. The calculated diffusion activation energy Ad is 9.9 kJ·mol-1. The value of the system reorganization energy Aris 39.8 kJ·mol-1, which is consistent with the theory of Markus - Dogonadze - Kuznetsov. Electrocatalytic activity of binary alloys of molybdenum with iron subgroup metals at 30 wt.% NaOH solution at this temperature is maximum and does not depend on the nature of the alloy. [ABSTRACT FROM AUTHOR]

In this work, a numerical approach is applied to study the impact of local cooling conditions on the hot tearing in an aluminium‐copper alloy with iron, magnesium and silicon as impurities. At first, CALPHAD‐coupled multicomponent and multiphase‐field simulations were performed to elucidate the effect of cooling conditions on solidification morphology in the final, critical stage of solidification. Then, the evolution of the melt flow permeability is derived from the simulated three‐dimensional microstructures and discussed in the context of the Rappaz‐Drezet‐Gremaud criterion for hot tearing susceptibility. With increasing cooling rates, the microstructure becomes finer and the resulting permeability first increases and then saturates within the investigated range. It is shown that the Rappaz‐Drezet‐Gremaud hot‐tearing criterion in combination with microstructure simulations responds to different cooling conditions in contrast to a Scheil‐Gulliver based model or an evaluation of the average Kou‐index. [ABSTRACT FROM AUTHOR]

The present paper reviewed the role of factors influencing the wear properties of iron alloy‐based coating material. In brief, these factors are categorized into four major types such as substrate properties, high‐velocity oxy‐fuel spraying parameters, heat treatment processes and wear testing parameters. Substrate properties include roughness, thermal resistance, and adhesive strength between substrate and coating materials. High velocity oxy fuel parameters include spray distance, oxygen flow rate, fuel flow rate, angle of spray, spray density, coating speed, thickness, number of coating layers etc. Erosion wear testing parameters include impact speed, impingement angle, erodent discharge, slurry concentration etc. Furthermore, erosion wear testing parameters are sub‐categorized into three types which are particulate‐based parameters such as size, shape and hardness of particle, impact‐based parameters such as angle of impact, impact velocity, and composition‐based parameters such as microstructure, physical and mechanical properties of materials. The annealing process speeds up the development of crystal phases. Therefore, to get the best coating materials, a detailed investigation and optimization of all the factors must be performed. [ABSTRACT FROM AUTHOR]

One of the strategies to combat micronutrient malnutrition is by developing biofortified common bean lines (Phaseolus vulgaris L.) capable of tolerating different stress conditions. In this study, the adaptive responses of different biofortified bean lines grown under combined stress of acidic soil and high-temperatures were evaluated in the Colombian Amazon. A total of 247 common bean lines from the Mesoamerican gene pool were used to determine the adaptive response in terms of phenological, physiological, and agronomic behavior under combined stress conditions. The lines tested were obtained from different single crosses, double crosses, and backcrosses between different bean materials, of which 146 were obtained from F4 families with high iron (Fe) content in seed and 99 common bean lines from F5 families. Different bean lines had grain yields (GY) higher than 1400 kg ha−1 from the F5 (lines: 859, 805, 865, and 657) and F4 (lines: 2853 and 2796) families. The superior performance of these lines was related to a higher photosynthate partitioning that has allowed an increase in pod formation (pod partitioning index, PPI) from the canopy biomass (CB) and grain filling (pod harvest index, PHI; harvest index, HI), resulting in higher values of GY. Values of GY were correlated with CB (r = 0.36), PPI (r = 0.6), PHI (r = 0.68), and HI (r = 0.8, p < 0.001). This increase in agronomic performance is due to a greater allocation of energy to the photosynthetic machinery (ΦII) and its dissipation in the form of heat (ΦNPQ), with increases in the leaf temperature difference (LTD). Based on the results obtained, six biofortified lines of common bean (lines F5: 859, 805, 865, and 657; lines F4: 2853 and 2796) showed traits of tolerance to combined stress and can serve as progenitors to increase Fe and Zn concentration in the seeds of lines that tolerate the combined stress from acidic soil and high temperature in the Colombian Amazon region. [ABSTRACT FROM AUTHOR]

Increasing the operating temperature and pressure of an automotive engine and reducing its weight can improve fuel efficiency and lower carbon dioxide emissions. These can be achieved by changing the engine piston material from conventional aluminum alloy to high-strength heat-resistant steel. American Iron and Steel Institute 4140 modified steels (AISI 4140 Mod.s), which have improved strength, oxidation resistance, and wear resistance at high temperature were developed by adjusting the AISI 4140 alloy compositions and optimizing the heat treatment process for automotive engine applications. In this study, the effects of modifying alloy compositions on the microstructure, mechanical properties (both at room and high temperatures), and oxidation of AISI 4140 Mod.s were investigated. Effective grain refinement occurred due to the influence of high-temperature stable carbide forming elements such as Mo, and V. The bainite structure changed to martensite structure under the influence Cr and Ni. As the Cr and W contents increased, the oxidation resistance was improved, and the oxide layer thickness decreased after 10 hours exposure at 500°C. The AISI 4140 Mod. exhibited a 35% improvement in room temperature strength, 70% improvement in high-temperature strength, and 40% improvement in high-temperature oxidation resistance compared to conventional AISI 4140. [ABSTRACT FROM AUTHOR]

The fire at Notre-Dame de Paris led to the discovery of several series of previously unknown iron armatures, which were systematically recorded. Amongst them, several iron staples from the top of the eaves walls, lead crest reinforcements and a sample of the tie rods used in the choir in the 19th century were analysed by metallography and tensile tests in order to determine their nature and mechanical characteristics. These results can be put into perspective with previous studies on such monuments. The chemical analysis with SEM-EDS of the slag inclusions contained in the matrix of these ferrous alloys makes it possible to determine the technical processes used for their production throughout the construction and restoration of the building, highlighting several differences depending on the typologies of the iron armatures. This information is complemented by a series of radiocarbon dates currently being carried out to better understand the periods of use of these ferrous reinforcements. When compared with those of other materials, these dates could be used to recalibrate the phasing of the building. [ABSTRACT FROM AUTHOR]

Ductile iron contains free graphite nodules within the metallic matrix, which generally consists of ferrite and pearlite in the as-cast condition. The casting thicknesses have a great influence on the size, shape, and quantity of the microconstituents of the metallic matrix and the graphite nodules and thus on the mechanical properties. In this study the cooling rate (caused by the casting thicknesses) on the metallic matrix and the nodular characteristics of a low alloyed ductile iron with 0.8 %Ni and 0.15 %V was investigated. The ductile iron was produced in a sandwich process with ladle inoculation. Six plates of different thicknesses, from 4.3 mm to 25.4 mm, were produced in a green sand mold. The microstructural characterization was performed by optical microscopy (OM), scanning electron microscopy (SEM), and the image J software using different quantification methods. The area method to determine the average nodule size and nodular structure provided more reliable results than the perimeter and total particle count methods. The hardness test on the Rockwell C scale was used for the mechanical characterization. The low content of vanadium added to the ductile cast iron had a negligible effect on the solidification pattern, which was mainly due to the graphitizing impact of the nickel and silicon addition. The results of the microstructural characteristics are therefore primarily due to the cooling rate, which is determined by the casting thickness. The thinnest casting section significantly improved the number of nodules (414 Nod/mm²), sphericity (0.96), and nodularity (96.21 %). In contrast, the thickest casting plate obtained the highest volume fraction of graphite (10.85 %) and the lowest volume fraction of unwanted particles (0.36 %). The high cooling rate in the thinnest casting plate resulted in the highest hardness of 31.56 HRC due to the higher volume fraction of the pearlite (33.7 %) and carbides (4.5 %). [ABSTRACT FROM AUTHOR]

Flux-cored arc welding (FCAW) is a universal group of welding methods in terms of the scope of application and automation possibilities, the share of which in various industries in many countries is still increasing. The paper presents the results of bibliographic analyses (scientometric analysis with the use of VOSviewer, Bibliometrix and CitNetExplorer tools) of a data set of 993 publications indexed in the Web of Science database on the subject of FCAW for all types of flux-cored wires. An objective and unbiased approach to analysis resulted in a relatively neutral assessment of the state of knowledge in the field of FCAW and allowed for the identification of research directions carried out in the world, the dynamics of their changes as well as research gaps and needs. The scientometric analysis approach provided a holistic picture of the development of FCAW over the last 58 years, pointing to the geographical areas where this process has been and is most intensively researched, the agencies funding this research, the most active research teams, as well as the journals that have most often published articles on this topic. The most current research directions in relation to FCAW include underwater welding, hardfacing and cladding purposes, health and safety issues, and more general topic: properties and weldability of ferrous alloys. However, among the most urgent research needs the following topics: fatigue analysis of welded joints, environmental degradation of flux-cored wires, properties and weldability of nickel alloys, development of hybrid and combined welding procedures can be listed. [ABSTRACT FROM AUTHOR]

The effect of complex alloying with iron, nickel, aluminum, zinc, zirconium and titanium in an amount of 0.5 – 1.2% each on the damping capacity of binary alloys Mn – 50% Cu and Mn – 40% Cu in the range of amplitude-independent damping is studied after aging at 643 K for 0.5 – 40 h and natural aging for 7 months. It is shown that alloying of the Mn – Cu alloys in cast condition may either raise their damping capacity or leave it invariable. With increase of the aging time, the values of the frequency of resonance vibrations of specimens of the Mn – Cu alloys fall to a minimum and then grow to a maximum level. The high damping capacity of the multicomponent Mn – 45.6% Cu – 1% Fe – 1% Ni – 1% Zn – 0.9% Zr – 0.5% Ti alloy (ψ = 2.9%) and of the Mn – 35.8% Cu – 1%Fe – 1%Ni – 1%Al – 1.2% Zr alloy (ψ = 3.5%) cast and aged for 40 h at 643 K does not decrease after 7 months of natural aging at 293 K. [ABSTRACT FROM AUTHOR]

Consumption of rare-earth metal (REM) oxides, such as cerium and lanthanum, is significantly lower than their production. This discrepancy is attributed to the complex extraction of all REMs, where the share of cerium is approximately 40%. This article proposes a method for processing REM oxides for their use as master alloys in ferrous metallurgy products. REMs, in the form of modifiers for steels and alloys, are widely used. However, despite their wide usage, owing to the complexity of the REM production technology, they tend to have a high market value. This study explores the preparation of a cerium carbide (CeC2) master alloy for the modification of steels and cast irons. The proposed method aims to reduce the cost of the alloying process and simultaneously increase the demand for REM oxides. Using a high-temperature synthesis process, CeC2 was obtained for the modification of steel and cast iron. For this purpose, cerium dioxide (CeO2), graphite (C), and ARMCO-iron (Fe) were mixed in a specific percentage ratio by weight: 5.4% C, 19.5% CeO2, and 75.1% Fe. Following this, the reaction mixture was heated in a furnace to a temperature of 1650°C and held for 30 min, with a residual pressure in the furnace of 10–1 mbar. The synthesis was performed in the temperature range of 1300–1650°C, with the highest reaction rate of at a temperature of 1520°C. Both elemental and X-ray diffraction analyses indicated that CeO2 was the end product of the synthesis process. The master alloy does not undergo hydrolysis because CeC2 is synthesized in the liquid phase of iron. It has been established that the technology for producing a cerium carbide alloy involving high-temperature heating in a resistive furnace, enables the production of a material with reproducible properties. [ABSTRACT FROM AUTHOR]

In this work the influence of various plasticizers on sintering powder materials based upon iron alloyed with copper is studied. It is shown that introduction of plastifiers into powder mixtures increases relative density by 4–10%. Performance of thermal mixing has a favorable effect on relative density after sintering. A workpiece after sintering with "warm" mixing has a relative density of 90–94%. The greatest relative volumetric shrinkage of 6.5% is observed for specimens of the composition PZhRV 2.200.28 + 0.7 wt.% Br + 0.7 wt.% Cu + 1 w t.% s t. C u + 1 wt.% Al2O3 mixed in a paddle mixer in a warm regime. Shrinkage is almost absent in specimens of composition PZHRV 2.200.28 + 0.7 wt.% Br + 0.7 wt.% Cu + 1 wt.% st. Cu. [ABSTRACT FROM AUTHOR]

This study investigates the impact of a high-entropy alloy filler metal coated with copper (Cu) and post-weld heat treatment (PWHT) on the weldability of a ferrous medium-entropy alloy (MEA) in gas tungsten arc welding. The addition of 1-at% Cu had an insignificant effect on the microstructural behaviour, despite a positive mixing enthalpy with other elements. It was observed that a small amount of Cu was insufficient to induce phase separation into the Cu-rich phase and refine the microstructure of the as-welded specimen. However, with an increase in the PWHT temperature, the tensile strength remained mostly consistent, while the elongation significantly increased (elongation of as welded, PWHT700, PWHT800, and PWHT 900 were 19, 43, 55 and 68%, respectively). Notably, the PWHT temperature of 900 °C yielded the most desirable results by shifting the fracture location from the coarse-grained heat-affected zone (CGHAZ) to base metal (BM). This was due to significant recrystallisation and homogenised hardness of the cold-rolled BM during PWHT. However, the CGHAZ with coarse grains induced by the welding heat input remained invariant during the PWHT. This study proposes a viable PHWT temperature (900 °C) for enhancing the weldability of cold-rolled ferrous MEA without additional process. [ABSTRACT FROM AUTHOR]

A356 alloy is widely used in the automotive industry for applications such as cylinder heads, engine blocks and other components. Iron contamination is a major problem with this alloy. The use of recycled aluminum alloys has increased annually due to sustainable and energy issues involved in production. The presence of iron in Al–Si alloys enables formation of the β-Al5FeSi phase, which negatively affects mechanical properties and forming processes. In the present study, A356 alloy was cast with 0.2, 1 and 3% wt. of iron to reproduce a recycling process. Cooling rates of 1.17 and 1.81 °C/s were used. The material was submitted to thermal treatment by solubilization and artificial aging. The effects of iron contamination on cutting force during cylindrical turning were investigated using cutting speeds of 363 and 720 m/min, feed rates of 0.08 and 0.3 mm/rev and 1.5 mm depth of cut. In order to determine the influence of the parameters, ANOVA was performed at 5% significance. The results showed that cutting force increased by 185.8% at higher feed rates and declined 6.4% at greater cutting speeds. Greater presence of the β-Al5FeSi phase reduced cutting force by up to 5.6% when compared to the uncontaminated alloy, indicating that β-Al5FeSi formation can be beneficial when only cutting forces are analyzed, since its presence tends to minimize these forces. A slight change in the cooling rate affected the cutting force by 2.2%. Influences were also observed for combinations of two factors. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of adding Mn to a 0.5%Cu-added A356 alloy on the interfacial layer formed between the alloy and cast iron in compound casting. The results showed that the interfacial compounds layer thickness and the types of phases constituting the layer were significantly influenced by the addition of Mn. Microstructural analysis of the interface revealed an increase in interlayer thickness with the addition of 0.3%Mn. Moreover, the almost absence of Al4.5FeSi phase in the interfacial layer, which is typically observed close to aluminum region, was noted when Mn was added. Instead, the formation of Al(Fe,Mn)Si phase containing Mn was observed with the addition of 0.3%Mn. The Mn-rich phase was identified as cubic-Al(Fe,Mn)Si phase through TEM analysis. Additionally, comparing the nanoindentation hardness of the interfacial compounds layer of the Mn-added alloy with that of the base alloy (0.5%Cu-added A356) showed that the hardness near the aluminum region was relatively higher in the Mn-added alloy. [ABSTRACT FROM AUTHOR]

High-silicon and molybdenum (SiMo) ductile iron is a common heat-resistant alloy that may be exposed to high-temperature wear during service in many of its applications. The wear behavior of four SiMo ductile iron alloys was evaluated at different temperatures up to 750 °C. This research focuses on the influence of various Mo contents on the microstructure, structural stability, and hence, the wear performance of such alloys. Thermodynamic calculations proposed the phase diagrams, critical transformation temperatures, and phase volume fractions in all samples by means of Thermo-Calc software. The dilatometry measurements were carried for confirming the theoretical results of Thermo-Calc thermodynamic calculations. The results revealed that the microstructure of SiMo ductile cast iron consists of nodular graphite and a ferrite matrix with carbides embedded in the fine precipitates at the grain boundary regions. The type of carbides and the nature of these fine precipitates are discussed according to EDX and SEM results. Adding molybdenum enhanced the wear performance of SiMo by decreasing the weight loss by about 40–70% compared to a Mo-free alloy. This is due to the increased molybdenum carbides, which increase hardness and improve wear resistance in SiMo alloys. The high temperatures have a negative effect on reducing the wear resistance at 250 °C. On the other hand, the wear resistance unexpectedly started to increase at higher temperatures of 500 °C and 750 °C because of the contribution of oxidative wear with abrasive wear by forming a protective oxide layer. Furthermore, the obtained results supported the idea that adding molybdenum improves wear resistance at high temperatures. Hence, SiMo has the potential to be wear-resistant material in wider applications requiring high-temperature wear resistance. [ABSTRACT FROM AUTHOR]

Austenite steel, Nb-bearing alloy steel, and high-Cr alloy cast iron surfacing layers (SL) were grown on 45 steel base metal (SBM) by using the arc surfacing method with self-shielded flux-cored welding wire and fusion electrode, and the composition and microstructure of these SLs were analyzed. The criss-cross push-off (CCPO) specimens for each type were processed, and the bonding property between SLs and 45 SBM was measured using a customized CCPO test. The fracture path and fractograph characteristics were also investigated using a metallographic and scanning electron microscope. The experimental results indicated that the bonding strength (BS) of austenite steel SLs and 45 SBM was the highest (465 MPa); the fracturing sites were near the fusion line, and the fracture exhibited cleavage fracturing features. The BS of niobium-bearing alloy steel and 45 SBM was 310 MPa, and the fracture was at the bottom of the SLs and exhibited quasi-cleavage fracturing features. The BS of the alloy cast iron SLs and 45 SBM was 175 MPa, and the fracture was at the bottom of the SLs and showed brittle fracturing features. [ABSTRACT FROM AUTHOR]

Fe-based biodegradable materials have attracted significant attention due to their exceptional mechanical properties and favorable biocompatibility. Currently, research on Fe-based materials mainly focuses on regulating the degradation rate. However, excessive release of Fe ions during material degradation will induce the generation of reactive oxygen species (ROS), leading to oxidative stress and ferroptosis. Therefore, the control of ROS release and the improvement of biocompatibility for Fe-based materials are very important. In this study, new Fe–Zn alloys were prepared by electrodeposition with the intention of using Zn as an antioxidant to reduce oxidative damage during alloy degradation. Initially, the impact of three potential degradation ions (Fe2+, Fe3+, Zn2+) from the Fe–Zn alloy on human endothelial cell (EC) activity and migration ability was investigated. Subsequently, cell adhesion, cell activity, ROS production and DNA damage were assessed at various locations surrounding the alloy. Finally, the influence of different concentrations of Zn2+ in the medium on cell viability and ROS production was evaluated. High levels of ROS exhibited evident toxic effects on ECs and promoted DNA damage. As an antioxidant, Zn2+ effectively reduced ROS production around Fe and improved the cell viability on its surface at a concentration of 0.04 mmol/l. These findings demonstrate that Fe–Zn alloy can attenuate the ROS generated from Fe degradation thereby enhancing cytocompatibility. [ABSTRACT FROM AUTHOR]

Recycling of aluminum (Al) alloys is critical to meet the demands of global net zero emission targets. The major challenge in the recycling of Al alloys is the presence of a higher content of iron as an impurity in Al alloy scraps, which deteriorates the mechanical properties of recycled alloys. In the present work, Al-7%Si alloys and Al-7%Si-2Fe alloys were cast at three different superheat temperatures to study the effect of superheat on the formation of iron intermetallic particles in these alloys. Microstructure–mechanical properties correlations were carried out using SEM-EDS and tensile testing of the alloys. 3D x-ray computed tomography (XCT) results show that the β-phase intermetallic particles were observed to be large and platelet-shaped in the Al-7Si-2Fe alloy cast at 700°C, while these particles appeared to be finer and uniformly distributed throughout the sample in the alloy cast at 900°C. XCT results show the presence of large shrinkage porosity in the Al-7Si-2Fe alloy cast at 700°C, due to the presence of large intermetallic particles which hinder the flow of molten metal during solidification of the alloys. Tensile test results show that the addition of 2% iron resulted in a significant reduction in the elongation of the alloy at all superheat temperatures. [ABSTRACT FROM AUTHOR]

The study of the effects of impurity on grain boundaries is a critical aspect of materials science, particularly when it comes to understanding and controlling the properties of materials for specific applications. One of the related key issues is the segregation preference of impurity atoms in the grain boundary region. In this paper, we employed the on-the-fly machine learning to generate force fields, which were subsequently used to calculate the segregation energies of phosphorus and silicon in bcc iron containing the ∑5(310)[001] grain boundary. The generated force fields were successfully benchmarked using ab initio data. Our further calculations considered impurity atoms at a number of possible interstitial and substitutional segregation sites. Our predictions of the preferred sites agree with the experimental observations. Planar concentration of impurity atoms affects the segregation energy and, moreover, can change the preferred segregation sites. [ABSTRACT FROM AUTHOR]

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An outstanding challenge in developing a complete equation of state for materials at elevated pressure and temperature is a robust method of determining the bulk temperature state under dynamic conditions. In metals, the determination of bulk temperature states by optical pyrometry is complicated by the small optical depth and thermal conduction effects. These effects lead to observed temperatures differing by 20% or more from the bulk temperature state. In this work, we show the presence of thermal conduction effects in temperature measurements of tin and iron coatings during dynamic compression experiments. We demonstrate that tin, in contrast to iron, coatings can fail to converge to a bulk temperature source over the time scale of the experiment, requiring the experimenter to modify assumptions, design, or analysis. This work bounds thermal transport at shocked conditions. [ABSTRACT FROM AUTHOR]