Fe Mn Research Articles

Static Recrystallization Behavior and Twin Formation Mechanism of Fe–Mn–Cr–N Steel During Medium Temperature Annealing

Static Recrystallization Behavior and Twin Formation Mechanism of Fe–Mn–Cr–N Steel During Medium Temperature Annealing

Additive manufacturing of Fe–Mn–Al–C lightweight steel by laser powder bed fusion: The role of laser scanning speed on forming quality, microstructure and properties

The Fe–Mn–Al–C lightweight steels have attracted great attention in the military, aerospace, and automotive industries due to their high strength and lightweight design. Nevertheless, the excessive Mn and Al inclusions have led to poor formability and processability, which brings challenges to the manufacture of large size complex structural parts. In this study, the lightweight steel with a composition of Fe–Mn–Al–C was prepared by laser powder bed fusion for the first time, aimed at investigating the effects of laser scanning speed. The results show that different laser scanning speeds have significant effects on the process sensitivity of lightweight steel, and too low or too high laser scanning speeds may lead to suboptimal sample quality, increased porosity and surface roughness. At a scanning speed of 800 mm/s, the optimal conditions for the lowest porosity (0.03%) and surface roughness (Sa = 3.34 μm) are achieved, resulting in the highest quality of the formed products. Furthermore, an increase in scanning speed results in a reduction in grain size and an enhancement of dislocation strength. When the scanning speed is 800 mm/s, the significant enrichment of Ni–Mn phase helps to enhance the pinning ability of dislocations, while the precipitation of nanoscale small and dense κ-carbide optimizes the Orowan strengthening effect. As a result, dislocation movement is effectively impeded, leading to superior comprehensive mechanical properties of exceptional strength-plasticity matched with a tensile strength, yield strength, and elongation after fracture of 1125.2 MPa, 1019.8 MPa, and 41.9%, respectively.

Influence of Al content on the microstructure and corrosion resistance in high manganese Fe–Mn–Al–C–Cr steels

Influence of Al content on the microstructure and corrosion resistance in high manganese Fe–Mn–Al–C–Cr steels

Microstructural and mechanical evolution of duplex Fe–Mn–Al–C steels during microstructural conditioning: Influence of vanadium microalloying

Microstructural and mechanical evolution of duplex Fe–Mn–Al–C steels during microstructural conditioning: Influence of vanadium microalloying

Trimetallic MOF–derived Fe–Mn–Sn oxide heterostructure enabling exceptional catalytic degradation of organic pollutants

Developing efficient and environmentally benign heterogeneous catalysts that activate peroxymonosulfate (PMS) for the degradation of persistent organic contaminants remains a challenge. Metal–organic frameworks (MOFs)–derived metal oxide catalysts in advanced oxidation processes (AOPs) have received considerable attention research fraternity. Herein, we report an innovative magnetic trimetallic MOF-derived Fe-Mn-Sn oxide heterostructure (FeMnO@Sn) with adjustable morphology, size and Sn content, prepared through an impregnation–calcination strategy. The formation of a novel magnetic Fe2O3/Fe3O4/Mn3O4 heterostructure induces the generation of abundant Fe2+ and Mn2+ sites on the FeMnO@Sn surface. Meanwhile, the introduction of SnO2 into the Fe2O3/Fe3O4/Mn3O4 heterostructure facilitates the cleavage of the OO bond in adsorbed PMS. The synergy among the different functionalities of each metal oxide plays a vital role in the swift and effective degradation of pollutants. In addition, the uniquely designed catalyst exhibits magnetic properties that facilitate easy recycling and repeated use, thereby meeting environmental protection requirements. Overall, this research highlights the design of heterogeneous catalysts for the effective activation of PMS and provides valuable insights for the advancement of future environmental catalysts.

Electrochemical reduction of nitrate to ammonia using Fe-based catalyst: Insights into N2, CO2, and CO environments

Electrochemical (EC) reduction of nitrate/nitrite for ammonia production is a key area of research in the realm of nitrogen pollutant treatment and recycling efforts. In this study, we utilized a commercial Fe(Mn) alloy to investigate EC reductions of nitrate/nitrite ions under N2, CO, and CO2-saturated conditions, shedding light on the influences of different feeding gases. Under N2 conditions, the ammonia production Faradaic efficiency (FE) reached 60 %; however, it significantly decreased under CO2 conditions. The presence of CO as a feeding gas proved detrimental, resulting in no ammonia production. Surprisingly, the Fe(Mn) alloy demonstrated superior EC Fischer-Tropsch (F-T) synthesis chemistry under CO conditions, generating CH4 and long-chain hydrocarbons (CnH2n+2 and CnH2n, where n=2–7). This contrasts with existing literature, where such alloys typically perform better under CO2 conditions. Notably, alkanes were found to be more predominant than their corresponding alkenes. The Anderson-Schulz-Flory equation plots exhibited significant linearity, resembling the traditional Fischer-Tropsch chain growth mechanism. This original discovery introduces new possibilities for employing commercial-grade Fe alloy in the direct EC F-T synthesis using CO, facilitating the production of long-chain hydrocarbons. Moreover, it paves the way for nitrate/nitrite ion treatments in analogous processes within diverse gas environments.

Microstructure and mechanical properties of Fe–30Mn–9Al–C–3Ni low-density steel manufactured by selective laser melting

Low-density Fe–Mn–Al–C steels are widely used in the automotive and aerospace industries as advanced lightweight materials. In this study, highly spherical Fe–30Mn–9Al–C–3Ni powder with a narrow particle-size distribution, low oxygen content, and good flowability was prepared using the plasma rotating electrode process (PREP). Furthermore, Fe–30Mn–9Al–C–3Ni low-density alloy steel was manufactured for the first time using the selective laser melting (SLM) molding technique. Laser power was found to significantly impact the microstructure and mechanical properties of SLM-printed Fe–30Mn–9Al–C–3Ni alloys. The Fe–30Mn–9Al–C–3Ni alloy prepared at a laser power of 110 W (denoted as P-110) exhibited the best mechanical properties, including a yield strength of 887.1 MPa, tensile strength of 1076.8 MPa, elongation of 40.80%, and a maximum hardness value of 294 HV. This study highlights the potential of SLM molding for fabricating low-density Fe–Mn–Al–C steels with complex geometrical shapes and outstanding comprehensive mechanical properties.

Microstructure, Damping Effect, Shape Recovery, and Nanoprecipitation of Hot and Cold Rolled Fe–30Mn–6Si–6Cr Shape Memory Alloy

Microstructure, Damping Effect, Shape Recovery, and Nanoprecipitation of Hot and Cold Rolled Fe–30Mn–6Si–6Cr Shape Memory Alloy

Boosting Microbial CO2 Electroreduction by the Biocompatible and Electroactive Bimetallic Fe–Mn Oxide Cathode for Acetate Production

Boosting Microbial CO₂ Electroreduction by the Biocompatible and Electroactive Bimetallic Fe–Mn Oxide Cathode for Acetate Production

Temperature dependence of the deformation behavior and mechanical properties of a Fe–Mn–Al–C low-density steel for cryogenic application

The temperature dependence of the deformation behavior and mechanical properties of a Fe–20Mn–6Al-0.6C-0.15Si austenitic low-density steel was studied by tensile test and Charpy impact test at −196 °C, −77 °C and room temperature (RT), followed by microstructure analyses. The results indicate that the decreased tensile temperature, which is corresponding to reduced stacking fault energy (SFE), promotes the planar glide of dislocations. This led to larger fraction of low-angle grain boundaries (LAGBs) at lower tensile temperature. Consequently, both the tensile strength and elongation were improved as temperature decreased. At lower impact test temperature, the load and energy of crack initiation were larger, indicating a higher resistance to crack initiation. However, the transition from stable to unstable crack propagation occurred more rapidly at lower temperature, resulting in lower crack propagation energy and reduced resistance to crack propagation. This is because less region experienced planar glide. Due to the rapid unstable crack propagation, the Charpy absorbed energy at −196 °C was the lowest. The smaller fracture surface area, larger fibrous zone and more obvious ductile fracture characteristics in radial zone suggest that the toughness is better at higher temperature. Additionally, the presence of secondary cracks at RT delayed fracture, therefore benefitting toughness.

Mineralogical and radiological studies on some Paleozoic yellow ochre deposits in Southwestern Sinai, Egypt

Yellow ochre is the basic material used in the manufacture of yellow oxide (a commercial product). Yellow ochre samples were taken from three different formations in southwestern Sinai: Abu Hamata, Um Bogma, and Abu Zarab. Yellow ochre occasionally exists in Abu Hamata Formation particularly in El Ferah area, associated with Fe–Mn ore in Wadi El Sahu (Um Bogma Formation) and in Himayer area (Abu Zarab Formation). The XRD analysis of the raw material reveals that they are mainly composed of goethite, which is associated with quartz and kaolinite in El Ferah area, hematite, kaolinite and quartz in Himayer area, and kaolinite, gypsum and quartz in Wadi El Sahu. The commercial product is mainly composed of goethite, quartz, and calcite. The heavy mineral investigation shows that some yellow ochre samples contain zircon and rare earth sulfate which may be responsible for the radioactivity of ochre due to their thorium and uranium content. The average values of specific radio-activities of most radionuclides in the samples of Himayer area I and II, and El Sahu I are higher than the respective world averages, while their activities are lower in El Ferah and El Sahu II. Th/U and Ra/U ratios exhibit vigorous changes in physico-chemical conditions during uranium leaching and deposition. Most of the radiological parameters in the ferruginous sediment and commercial product samples from El Ferah, El Sahu II, and Himayer II are lower than the recommended international values but higher than those from Himayer I and El Sahu I samples. The plotted hierarchical cluster analysis (HCA) exhibits that the main contributors for the hazards of these sediments and their commercial product are 238U, 232Th and 226Ra in Himayer I &II, commercial products, and El Ferah area, 232Th and 226Ra in El Sahu II , 232Th, 40K and 226Ra in El Sahu I.

Influence of Organic Compounds on Ni, Co, Cu, Cr, and Pb Accumulation by Nodules in Agro-Dark-Humus Podbels (Planosols) in the South of Primorskii Region

The involving of organic compounds in accumulation of Ni, Co, Cu, Cr, and Pb by Fe–Mn nodules in agro-dark-humus podbels (Planosols (Aric)) under different types of long-term agrotechnical impact has been studied in the south of Primorskii region. The profile patterns of the level of SOC content in soils and in nodules indicate the active deposition of organic compounds in nodules in the lower parts of soil profiles in the of fallow and phytomeliorative variants of the experiment. Fulvic acids were noted to predominate in the composition of humus in the nodules in these variants. The long-term application of organic fertilizers contributed to the decrease of SOC incorporation into nodules and to the increase of the part of humic acids in nodules. Nodules were characterized by a high accumulation levels of Co and Pb in all variants of the experiment. Accumulation of Ni, Cr, and Cu was recorded in nodules from particular horizons of studied soils. The intensity of elements accumulation in nodules of different variants of the experiment varied. Accumulation of Ni was controlled by the content of Mn-containing compounds. The most active sorption phases of nodules from soils with a longer period of organic matter transformation (fallow variant and long-term addition of manure variant) were Fe-containing and organic compounds.

Damping capacity in cast FeMn binary alloys

There were few works on cast FeMn binary damping alloys, although many studies have been conducted on deformation-processed counterparts. The cast Fe(15–21)Mn alloys were prepared to investigate their damping capacity in this work. The optimal Mn contents for damping capacity in both the as-cast FeMn binary alloys and solution-treated ones was ∼ 19 %, 2 % higher than that in the deformation-processed counterparts. The solution treatment obviously improved the damping capacity in the as-cast Fe15Mn alloys but remarkably deteriorated the damping capacity in the as-cast FeMn alloys with the Mn content above 17 %. An inverse dependence on the amount of α′-martensite existed in both the as-cast Fe(15–19)Mn alloys and solution-treated ones, but the dependence was weak in the latter. The dual role played by the α′-martensite could explain the different effects of it on the damping capacity.

Microstructure and Mechanical Properties of Gas Metal Arc-welded Fe–Mn–Si Seismic Damping Alloy

Microstructure and Mechanical Properties of Gas Metal Arc-welded Fe–Mn–Si Seismic Damping Alloy

Assessment of REY resource potential in deep-sea sediments with Fe–Mn (oxyhydr)oxides in the Pacific Ocean

Deep-sea sediments with an abundance bioapatites and Fe–Mn (oxyhydr)oxides in the Pacific Ocean have been considered potential reservoirs of rare earth elements and yttrium (REY). However, comprehensive assessment of the resource potential of REY in deep-sea sediments with Fe–Mn (oxyhydr)oxides throughout the Pacific Ocean is limited due to difficulties in accurately predicting the distribution of extensive Fe–Mn (oxyhydr)oxides and the associated REY. In this study, we predicted the prospective area and resource potential of REY-rich sediments with Fe–Mn (oxyhydr)oxides by considering multiple factors that control REY enrichment based on data from International Ocean Discovery Program (IODP) samples and previous research. According to the distribution map inferred by comprehensively evaluating lithology (clay sediment), hydrothermal fluid influence (δ3He), and water depth (bathymetry), deep-sea sediments with Fe–Mn (oxyhydr)oxides, which have higher than 1000 ppm REY concentration, are distributed in the vicinity of the East Pacific Ridge within a water depth range of 4000–4600 m, and their distribution area is estimated to be approximately 1.1 million km2. If the sedimentation rate (<1.5 m/Myr) is considered, which is a crucial factor influencing REY enrichment, we can achieve a more precise assessment of their distribution area. Assuming a recovery depth of only 1 m, the REY resource amount was estimated to be approximately >450 million tons of REY oxide. Even without accounting for REY resource amount associated with bioapatite, the minimum REY resource amount estimated in this study exceed the world's current land reserves. Furthermore, these sediments contain a significant abundance of industrially important heavy REY, accounting for 53 % of REY resources. This implies that the deep-sea sediments with Fe–Mn (oxyhydr)oxides in the Pacific Ocean are a promising resource of REY. Our findings will serve as essential information for the technological progress required in the exploration and development of REY resources in deep-sea sediments in the future.

Nano silica-mediated stabilization of heavy metals in contaminated soils

Soil contamination with heavy metals presents a substantial environmental peril, necessitating the exploration of innovative remediation approaches. This research aimed to investigate the efficiency of nano-silica in stabilizing heavy metals in a calcareous heavy metal-contaminated soil. The soil was treated with five nano-silica levels of 0, 100, 200, 500, and 1000 mg/kg and incubated for two months. The results showed that nano-silica had a specific surface area of 179.68 m2/g\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{m}}^{2}/\ ext{g}$$\\end{document}. At 1000 mg/kg, the DTPA-extractable concentrations of Pb, Zn, Cu, Ni, and Cr decreased by 12%, 11%, 11.6%, 10%, and 9.5% compared to the controls, respectively. Additionally, as the nano-silica application rate increased, both soil pH and specific surface area increased. The augmentation of nano-silica adsorbent in the soil led to a decline in the exchangeable (EX) and carbonate-bound fractions of Pb, Cu, Zn, Ni, and Cr, while the distribution of heavy metals in fractions bonded with Fe–Mn oxides, organic matter, and residue increased. The use of 1000 mg/kg nano-silica resulted in an 8.0% reduction in EX Pb, 4.5% in EX Cu, 7.3% in EX Zn, 7.1% in EX Ni, and 7.9% in EX Cr compared to the control treatment. Overall, our study highlights the potential of nano silica as a promising remediation strategy for addressing heavy metal pollution in contaminated soils, offering sustainable solutions for environmental restoration and ecosystem protection.

Zeolite functionalized with macroalgae as novel material for Fe and Mn removal from real acid mine drainage

The treatment of heavy metals such as Fe and manganese Mn remains a critical global issue, necessitating solutions that are not only effective and efficient but also cost- effective and easy to implement. Adsorption has been identified as one of the most efficient techniques for removing heavy metals. This study investigates adsorption method applied to real AMD, characterized by high levels of heavy metal contamination and low pH. Key parameters analyzed include adsorption performance, isotherm and kinetic models, thermodynamic properties, and adsorption characteristics. The adsorbent used was zeolite functionalized with carboxyl, hydroxyl, and sulfate groups derived from macroalgae. Material characterization was conducted using SEM, XRD, and FTIR. The results indicate that zeolite functionalized with carboxyl, hydroxyl, and sulfate groups from macroalgae effectively reduced Fe and Mn concentrations by up to 99 % within just five minutes. Furthermore, the adsorption process followed a pseudo-second-order kinetic model and conformed to the Langmuir isotherm model.

Effect of temperature and time on the precipitation of κ-carbides in Fe–28Mn–10Al–0.8C low-density steels: Aging mechanism and its impact on material properties

Effect of temperature and time on the precipitation of κ-carbides in Fe–28Mn–10Al–0.8C low-density steels: Aging mechanism and its impact on material properties

Simultaneously enhancing the strength and ductility of Fe–Mn–C twinning-induced plasticity steel via Cr/N alloying

The effect of Cr/N alloying on the tensile deformation behavior of Fe–Mn–C twinning-induced plasticity steel was investigated through monotonic tensile tests, X-ray diffraction, electron back-scattered diffraction, transmission electron microscopy, and digital image correlation technique. The results demonstrate that the addition of Cr/N significantly enhances both the strength and ductility of Fe–18Mn-0.6C steel while dynamic strain aging (DSA) behavior weakens or even disappears. Compared with that in the Fe–18Mn-0.6C steel, more densely-spaced, thinner deformation twins were formed in the Cr/N-alloyed steel. Moreover, the Cr/N additions promote deformation twins to form over a wider strain range. This unique twinning behavior leads to a sustained high strain-hardening rate at higher strains, thereby delaying plastic instability and concurrently enhancing strength and ductility.

The Characteristics and Enrichment Process of Dabu Ion-Adsorption Heavy Rare-Earth Element (HREE) Deposits in Jiangxi Province, South China

Ion-adsorption rare-earth deposits supply over 90% of the global market’s heavy rare-earth elements (HREEs). The genesis of these deposits, particularly HREE deposits, has garnered significant attention. To elucidate the metallogenic mechanisms of HREE deposits, a comprehensive study of the weathering profile of granite was conducted in Jiangxi Province, South China. This study focuses on the following two aspects: the petrogeochemistry of HREE-rich granite and the enrichment and fractionation of rare-earth elements (REEs) during the weathering process. The results suggest that the Dabu granites are a typical peraluminous, high-K, calc-alkaline granite series with high silica content (SiO2: 74.5%–76.4%), relatively low phosphorus content (P2O5: &lt;0.05%), and high HREE content (ΣLREE/ΣHREE: 0.16–0.66). Weathering advances the decomposition of minerals and the release of elements. REEs are mainly fixed in the regolith by scavengers, mainly clays, Fe–Mn oxides, and carbonates, and ΣREE can reach 799 ppm in the B horizon. However, HREEs tend to migrate further and preferentially combine with Fe–Mn oxides and carbonates as compared to LREEs, leading to a significant fractionation of REEs in the regolith (ΣLREE/ΣHREE = 0.2–1.1). Additionally, the differential weathering of REE-bearing minerals and the precipitation of secondary REE-bearing minerals are also vital for REE fractionation.