Manganese Alloys Research Articles

Molecular Dynamics Study of the Deformation Processes of Metallic Materials in Structural and Phase (Martensitic) Transformations

The application of the method of molecular dynamics based on the use of pair interatomic potentials has been discussed to study various deformation processes during structural and phase (martensitic) transformations in metallic single and polycrystals. It has been shown that the method of molecular dynamics in a two-dimensional model makes it possible to qualitatively analyze the processes of grain-boundary sliding and other mechanisms of plastic deformation in polycrystals. It is also an efficient tool for describing diffusionless martensitic transformations in metallic materials. As an example, the use of the method for simulating grain-boundary sliding in a polycrystal with nonequilibrium grain boundaries is presented and the mechanisms of overcoming an obstruction in the form of a protruding segment of a grain have been demonstrated at the atomic level. The application of this method for describing the dynamics and morphology of the thermoelastic martensitic transformation has been illustrated by the example of the titanium nickelide and manganese alloys.

On the Possibility of Using Manganese Carbonate Ores in Ferromanganese Industry

The problem of energy consumption in the ferroalloy industry has become an enormous challenge as the cost of energy permanently increases, while the reserves of good-quality raw materials are decreasing. Hence, the valorization of low-quality raw materials becomes necessary under the conditions of keeping the quality of products within the marketable range and low energy consumption. From the history of smelting of manganese alloys, it is known that the priority was always given to high-grade manganese-oxide ores because the quality of the ore has a great influence on numerous important parameters. This was mainly connected with the pyro metallurgical advantages offered by high-grade ores, including high manganese content (minimizing the materials consumption), lower power consumption caused by its oxide nature, and high fusibility. However, in the last 50 years, the ferroalloy industry faces the problem of application of the carbonate ores with an aim to compensate the depletion of the reserves of oxide manganese ores and meet the requirements of steelmaking in which manganese alloys find their primary use. In the present work, we study two manganese ores, namely, pure oxide and carbonate ores. A jones riffle was used for sample preparation. A jaw crusher and zip mill were used to decrease the size of particles, a graphite crucible was used as the container of the ore, and an induction furnace was used for smelting. Various proportions of oxides and carbonates manganese ore were mixed and smelted at 1550°C in the argon atmosphere for 1 h. The investigations of the ores and products were carried out by using the x-ray diffraction (XRD) method, an ICP-OES spectrometer, and a scanning electron microscope with energy dispersive spectrometer. It was shown that a marketable high-carbon ferromanganese can be produced with at least 75% Mn and a slag containing less than 20% MnO. The results obtained for oxide-carbonate blends with 90–10%, 80–20%, 70–30%, 60–40%, and 50–50% ratios met market requirements. However, the results accumulated for oxide-carbonate blends with 20–80% and 0–100% ratios showed that the alloys obtained as a result of smelting contained only 48% Mn and 68% Mn, respectively, despite the fact that the slag contained ≤20% MnО.

Magnetically Driven Pump for Solid-State Microfluidic Flow Control

Microfluidics is a rapidly developing field due to the many advantages that handling fluids in the microliter and nanoliter scale. This includes reduced volumes of samples and reagents used, quicker processing times and more precise and consistent results. A key requisite to exploit these advantages is fluid control at the nanoliter scale. Fluid handling systems that can accurately dose the volumes needed in microfluidics are underdeveloped, particularly options that are small and easy to manufacture. Some options include capillary flow, electroosmotic, piezoelectric and peristaltic technologies. The magnetic shape memory (MSM) pump is similar in principle to a peristaltic pump except that there are no mechanical parts such as gears or valves. The MSM material itself replaces the classical mechanical components found in traditional pumping mechanisms. The material is the machine. The MSM material is an alloy of nickel, manganese and gallium (Ni-Mn-Ga). The MSM effect, which is the coupling of the material’s atomistic and magnetic structures, is responsible for the large shape change (up to 10%) that has been observed in the single crystalline material. Through a process known as twinning, the crystallographic structure of the material can be manipulated by converting energy from an applied magnetic field. This is advantageous in that the material’s shape can be precisely changed without contacting the device itself. The MSM pump is realized when this material is integrated into a microfluidic channel and controlled using a localized magnetic field. The material becomes a metal muscle. The MSM pump is a solid-state microfluidic flow control device that operates similar to a peristaltic pump. The material’s shape changes to create a cavity at the inlet channel due to a locally applied, external magnetic field. The formation of this cavity creates a negative pressure which is then filled with a bolus of fluid from the outlet. This cavity is then translated across the material until it reaches the outlet channel, at which it is then ejected from the material and into the microfluidic system. There are no moving parts, such as gears or check valves, in the micropump itself. The current peristaltic MSM micropump has a resolution of 40 – 150 nL per complete pumping cycle. New techniques have been developed to achieve a resolution nearing 1 – 2 nL. The MSM pump has repeatable, stable performance even at pumping pressures exceeding 100 kPa and can pump both gas and liquids (and is thus self-priming). Furthermore, the material acts simultaneously as both the pumping mechanism and a valve. This multi-functionality, and the simplicity of the overall MSM pump, make it a competitive technology for devices requiring flow rates from nearly zero to 1,500 µL/min, particularly devices where the pumping mechanism must be integrated directly into the microfluidic device such as a lab-on-a-chip, as shown in the figure. Using the MSM pump, we created and manipulated a droplet lipid bilayer and delivered sub-microliter volumes of the electrically controlled nano-valve lysenin. We will present the performance of the MSM pump as well as the results from these recent experiments. This demonstrates the capabilities of this technology and illustrates its capacity for other applications within the field of microfluidics. Figure 1

Estimation of PM10-bound manganese concentration near a ferromanganese alloy plant by atmospheric dispersion modelling

Numerous studies have associated air manganese (Mn) exposure with negative health effects, primarily neurotoxic disorders. This work presents a description of the emission and dispersion of PM10-bound Mn from industrial sources in the Santander bay area, Northern Spain. A detailed day-specific emission estimation was made and assessed for the main Mn source, a manganese alloy production plant under 8 different scenarios. Dispersion analysis of PM10-bound Mn was performed using the CALPUFF model. The model was validated from an observation dataset including 101 daily samples from four sites located in the vicinities of the manganese alloy plant. Model results were in reasonable agreement with observations (r = 0.37; NMSE = 2.08; Fractional Bias = 0.44 and Modelled/Observed ratio = 1.57). Simulated and observed Mn concentrations in the study area were much higher than the guidelines proposed by the World Health Organization (WHO) and the U.S. Environmental Protection Agency (USEPA), highlighting the need to reduce the Mn concentrations in the area. Based on the analysis of the Mn source contribution from the ferromanganese alloy plant, some preventive and corrective measures are discussed at the end of the paper. This work shows that CALPUFF dispersion model can be used to predict PM10-bound Mn concentrations with reasonable accuracy in the vicinities of industrial facilities allowing the exposure assessment of the nearby population, which can be used in future epidemiological studies.

In Vivo Evaluation of Biodegradability and Biocompatibility of Fe30Mn Alloy.

This study aims to evaluate the biodegradability and biocompatibility of an alloy of iron and manganese (Fe30Mn) in a bone model in vivo. Resorption of a Fe30Mn wire was compared with traditional permanent 316L stainless steel (SS) wire after bilateral transcondylar femoral implantation in 12 rats. Evaluation of biodegradation over 6 months was performed using radiography, post-mortem histology and microscopic implant surface analysis. Corrosion and resorption of the novel iron-manganese implant with formation of an iron oxide corrosion layer was noted on all post-mortem histological sections and macroscopic specimens (corrosion fraction of 0.84 and 0 for Fe30Mn and 316L SS, respectively). Increased bone ongrowth was observed at the wire-bone interface (bone ongrowth fraction of 0.61 and 0.34 for Fe30Mn and 316L SS, respectively). Occasionally, poorly stained newly formed bone and necrotic bone in contact with corrosion was seen. In bone marrow, Fe30Mn alloy was scored as a mild local irritant compared with 316L SS (biocompatibility score of 8.8 and 5.3, respectively). There was no evidence of systemic adverse reaction. Resorbable iron-manganese alloys may offer a promising alternative to permanent metallic implants. Further in vivo studies to control implant resorption at a rate suitable for fracture healing and to confirm the biocompatibility and biosafety of the resorbable Fe30Mn metallic implant are necessary prior to use in clinical settings.

Recovery of Soluble Potassium from Electric Arc Furnace Dust of Manganese Alloy Production: Characterization and Water Leaching Kinetics

Recovery of Soluble Potassium from Electric Arc Furnace Dust of Manganese Alloy Production: Characterization and Water Leaching Kinetics

Global optimisation of multi-plant manganese alloy production

This paper studies the problem of multi-plant manganese alloy production. The problem consists of finding the optimal furnace feed of ores, fluxes, coke, and slag that yields output products which meet customer specifications, and to optimally decide the volume, composition, and allocation of the slag. To solve the problem, a nonlinear pooling problem formulation is presented upon which the bilinear terms are reformulated using the Multiparametric Disaggregation Technique (MDT). This enables global optimisation by means of commercial software for mixed integer linear programs. We demonstrate the model and solution approach through case studies from a Norwegian manganese alloy producer. The computational study shows that the model and proposed optimisation approach can solve problem sizes of up to ten furnaces to a small optimality gap, that global optimization approach with MDT scales well with larger, real problem instances, and that the model outperforms the current operational practice.

Effect of aluminium on the microstructure and mechanical properties of as-cast magnesium–manganese alloys

ABSTRACTIn this paper, the effect of aluminium on microstructure and mechanical properties of as-cast magnesium–manganese alloy has been investigated by means of X-ray diffraction, optical microscopy and scanning electron microscopy. The results reveal that various Al–Mn intermetallic compounds form with an increase of Al content. As a result, microstructure of AM11 alloy has been effectively refined due to the formation of Al8Mn5 phase along the grain boundary, while Al addition is explained as the main reason on refining the microstructure of AM91 alloy due to its higher grain growth restriction factor value of ∼4.32. The tensile yield strength (TYS) has been improved steadily from 27.4 to 122.9 MPa with increasing Al content, because of the combined effects of grain boundary strengthening, solid solution strengthening and precipitation hardening behaviours.

Electrodeposition of Manganese Thin Films from Choline Chloride/Urea Based Ionic Liquids

Manganese and its alloys are of significant interest for a variety of applications from corrosion resistance to thin films with useful semiconducting and magnetic properties. Manganese alloys have been demonstrated to have high Seebeck coefficients suitable for use as thermoelectric materials, have antiferromagnetic properties, and can be used to form dilute magnetic semiconductors.[1-3] Electrodeposition provides an attractive method to grow uniform thin films of these materials, however manganese is difficult to deposit in high quality from aqueous solutions due to the simultaneous hydrogen evolution reaction.[4] Despite the growing amount of literature on the electrodeposition of manganese alloys and compounds from various ionic liquids,[5-6]there is little known on the deposition of metallic manganese films, which is paramount to properly designing processes for alloy or compound deposition. This work aims to provide an in-depth study of the deposition of metallic manganese from an ionic liquid consisting of a 1:2 ratio of choline chloride and urea (ChCl-urea), a solvent that is seeing rapidly increasing use due to its low cost and good stability. The effect of glycine, which has been commonly used in aqueous systems, will also be studied in this ionic liquid media. Initial cyclic voltammetry studies coupled with partial current measurements (figure 1) indicate an onset of cathodic manganese deposition at -1.17 V vs an Ag wire pseudo reference electrode. X-ray fluorescence (XRF) was used to measure deposit thicknesses in order to determine partial current densities of the manganese deposition reaction. The addition of glycine is observed to increase the side reaction that occurs prior to and during manganese deposition during cyclic voltammograms. It also inhibits manganese deposition, the onset of which is shifted to more negative potentials. The inhibiting effect of glycine is manifested as a reduction in the partial current of manganese deposition and an increase in the partial current of side reactions. Surface morphologies of deposits obtained at various current densities, with and without glycine, were studied using SEM and XRD. Results indicate that films grown with and without glycine exhibit similar morphologies, however feature sizes are larger in films grown from glycine containing baths, consistent with expectations for a slower growth process. In all cases, films were uniform and absent of significant cracking, indicating that this may be an attractive method for creating high quality thin films of manganese and its alloys, while avoiding the issues encountered with aqueous deposition baths.

Characterization of manganese-bearing particles in the vicinities of a manganese alloy plant

Numerous studies have associated air manganese (Mn) exposure with negative health effects, primarily neurotoxic disorders. Despite there is not a specific European regulation, institutions such as the World Health Organization (WHO) have proposed an annual average guideline value of 150 ng/m3. Bioaccessibility and toxicity mechanisms of Mn remain unclear, however it is generally agreed that adverse health effects are strongly linked to particle size and morphology, chemical composition and oxidation state. This study aims to deepen the understanding of the physico-chemical characteristics of PM10 and deposition samples collected in an urban area in the proximities of a ferromanganese alloy plant. Total Mn content was determined by ICP-MS after a microwave-assisted acid digestion. The size, morphology and chemical composition of individual particles were studied by SEM-EDX. XRD was used to identify the major crystalline phases. Most of the particles observed by SEM-EDX contain Mn. 60% of Mn-PM10 particles were spheres of small size and were attributed to condensation processes at the smelting unit. Mn-bearing particles present in deposition were characterized by irregular shapes and bigger sizes, most of them consisting of SiMn slags and Mn ores and alloys, and attributed to diffuse emissions from raw material and product handling and processing. Due to the differences in the characteristics of Mn-bearing particles found in the different matrices, further studies on the potential toxicity and health effects of these particles should be done, especially in relation with the small and spherical particles present in PM10, which are expected to be more problematic.

Calculations of manganese ferroalloys production efficiency from different ores

The cost of producing manganese alloys by reduction from manganese ore using carbothermic process is estimated. Alternatives of FeMn78 and SiMn17 production from rich Australian manganese ore with low-phosphorus concentration or low-phosphorus manganese slag in charge mixture with poor domestic Russian ore with comparatively high phosphorus content are calculated and presented in the article. Direct production costs for alternative variants in a wide range of cherge composition are estimated.

Accelerated Rusting of Reinforcing Bars: The Role of Manganese Alloying in Concrete Reinforcement Steel Bars

The role of alloying of manganese in mild carbon steel reinforcing bar on the rate of atmospheric rusting is investigated. Four types of steel reinforcing bar from different producers having variations in the rate of atmospheric rusting were collected and exposed to the atmosphere of Jamshedpur, India for 3 years. The corrosion rates of the exposed reinforcing bar samples were evaluated by determining the loss in weight of the samples. A direct relationship has been recorded between the rate of corrosion and the manganese content in the steel. The corrosion products formed on the surface of the exposed reinforcing bar samples were characterized by Raman spectroscopy and X-ray diffraction techniques. Electro-chemical impedance spectroscopy and DC polarization studies of the reinforcing bar samples were also performed to understand the causes for the difference in their rates of rusting. The mechanism for the accelerated rate of rusting recorded for the higher manganese-containing steel is discussed by proposing a schematic model incorporating different stages of reactions.

Evaluation of particulate matter emissions from manganese alloy production using life-cycle assessment

Life-cycle assessments (LCAs) provide a wealth of industry data to assist in evaluating the environmental impacts of industrial processes and product supply chains. In this investigation, data from a recent LCA covering global manganese alloy production was used to evaluate sources of particulate matter (PM) emissions associated with the manganese alloy supply chain. The analysis is aimed at providing an empirical, industry-averaged breakdown of the contribution that processes and emissions controls have on total emissions, manganese releases and occupational exposure.The assessment shows that 66% of PM emissions associated with manganese production occur beyond manganese facilities. Direct or on-site emissions represent 34% of total PM and occur predominantly as disperse sources during mineral extraction and hauling, and as primary furnace emissions. The largest contribution of manganese-bearing PM at ground-level is associated with fugitive emissions from metal and slag tapping, casting, crushing and screening.The evaluation provides a high-level ranking of emissions by process area, to assist in identifying priority areas for industry-wide initiatives to reduce emissions and occupational exposure of manganese. The range of PM emission levels in industry indicate that further enhancements in PM emissions can be achieved by sharing of best practices in emissions controls, limiting furnace conditions which lead to by-passing of emissions controls and application of secondary emission controls to capture fugitive emissions during tapping and casting. The LCA approach to evaluating PM emissions underscores the important role that process optimization and resource efficiency have on reducing PM emissions throughout the manganese supply chain.

Effect of gas-forming additions on the parameters of layers in plasma powder surfacing

To protect deposited metal against oxidation in plasma powder surfacing, test was carried out with the process of combined supply of the powder and gas-forming additions. The effect of the parameters and the amount of sodium fluoride on the geometrical dimensions of the layers in surfacing chromium–nickel and chromium–manganese alloys is determined.

Chemical composition and atomic structure of the surface of copper–manganese alloy modified with oxygen ions

The regularities of the formation of the chemical composition of thin surface layers of Cu–Mn alloy under irradiation with oxygen ions in the pulse-periodic mode with different parameters of exposure are investigated by X-ray photoelectron spectroscopy (XPS). We study the distribution patterns and chemical state of the alloy elements in the ion-implanted layers, depending on the dose and energy of irradiation. It is found that with increasing irradiation dose, the alloy components are redistributed in the surface layers, and increasing ion energy leads to decomposition of the initial solid solution.

Influence of Heat Treatments on the Microstructural Evolution and Resultant Mechanical Properties in a Low Carbon Medium Mn Heavy Steel Plate

In this study, the microstructural evolution and resultant mechanical properties in a low carbon medium Mn heavy steel plate were investigated in detail. The results show that the introduction of medium manganese alloy design in the heavy steel plate has been shown to achieve the outstanding combination of strength, ductility, low-temperature impact toughness, and strain hardening capacity. It has been found that the austenite phase mainly displays at martensitic lath boundaries and shows lath shape for the heat treating at 873 K (600 °C) for 1 to 10 hours or 893 K (620 °C) for 2 hours, and not all the austenite phase obeys the K–S or N–W orientation relationship with respect to abutting martensitic lath. Although the microstructure in the steel after heat treating at 873 K (600 °C) for 1 to 10 hours is similar to each other, the resultant mechanical properties are very different because the volume fraction and stability of retained austenite vary with the heat treatments. The best low-temperature impact toughness is achieved after heat treating at 873 K (600 °C) for 2 hours due to the formation of a considerable volume fraction of retained austenite with relatively high stability, but the strain hardening capacity and ductility are disappointing because of insufficient TRIP effect. Based on enhancing TRIP effect, the two methods have been suggested. One is to increase the isothermal holding temperature to 893 K (620 °C), and the other one is to prolong the isothermal holding time to 10 hours at 873 K (600 °C). The two methods can significantly increase strain hardening capacity and ductility nearly without harming low-temperature impact toughness. In addition, the stability of retained austenite has been discussed by the quantitative analysis and it has been demonstrated that the stability of retained austenite is related to the chemical composition, size, and morphology. Moreover, the isothermal holding temperature has a great effect on the stability of retained austenite, while the effect of the isothermal holding time is relatively poor.

Influence of Boronizing Treatment on Fe–Mn–Al–Si–C Steel

Abstract Austenitic Fe–Mn–Al–Si–C steel provides excellent cold formability and lower density compared to conventional stainless steels. These steels owe their corrosion and oxidation resistance to their aluminum and silicon contents, and the stability of their gamma phase is due to manganese and carbon alloying elements. The production of a boride layer with high hardness can significantly increase its surface hardness and consequently its wear resistance. In this work, Fe–31Mn–7.5Al–1.3Si–0.9C steel samples were subjected to a boriding treatment for 4 h at 900°C. The composition of the bath was 90 % borax and 10 % aluminum. Boride layers with high hardness levels were obtained (1900 HV). There was also a marked increase in wear resistance of the material.

Cradle-to-gate life cycle assessment of global manganese alloy production

Manganese is a metal used extensively in everyday life, particularly in structural steel. Despite the importance of manganese as an essential alloying element in steel and stainless steel, the environmental profile of manganese alloys lacked globally representative, primary industry data. The International Manganese Institute (IMnI) and Hatch completed the first global life cycle assessment (LCA) of manganese alloy production, providing environmental benchmarks and a firm foundation of accurate data with which to inform other industry-led initiatives. The study compiled primary data from 16 ore and alloy producers worldwide, covering 18 % of global ore production and 8 % of global alloy production for 2010. This peer-reviewed, ISO 14040 compliant LCA covers the cradle-to-gate life cycles of silicomanganese, ferromanganese, and refined ferromanganese. The study provides a comprehensive picture of global environmental performance, quantifying energy consumption, global warming potential (GWP), acidification potential (AP), photochemical ozone creation potential (POCP), primary water use, and primary waste generation. A novel model architecture was devised to generate process, site, and cradle-to-gate LCAs for single and multiple sites simultaneously, extracting greater value from the LCA process by facilitating environmental and operational benchmarking within the industry. The results of the study show that total GWP, AP, and POCP for 1 kg of average manganese alloy was 6.0 kg CO2e, 45 g SO2e, and 3 g C2H4e, respectively. Electricity demand and coal and coke consumption during smelting are the dominant operating parameters contributing to environmental performance. On-site air emission measures (GWP, POCP, NOX, and particulate matter (PM)) contributed 25 to 35 % of total life cycle emissions. Overburden and waste rock were the most significant primary solid waste flows by mass. The study provides a resource for improvement at the global industry and site scales by establishing benchmarks, identifying hotspots, and quantifying the benefits of efficiency savings through process optimization. This LCA provides accurate primary data to improve steel and stainless steel product LCAs and communicate the environmental performance of the industry in quantitative terms. It facilitates dialogue between manganese producers and consumers through a shared understanding of the environmental profile of the industry. Through leveraging the study to identify hotspots within the manganese supply chain, producers can work both independently and collectively towards improving the environmental and economic performance of manganese alloys.

Effect of Ca addition on the corrosion behavior of Mg–Al–Mn alloy

The microstructures and corrosion resistance of magnesium–5wt% aluminum–0.3wt% manganese alloys (Mg–Al–Mn) with different Ca additions (0.2–4wt%) were investigated. Results showed that with increasing Ca addition, the grain of the alloys became more refined, whereas the corrosion resistant ability of the alloys initially increased and then decreased. The alloy with 2wt% Ca addition exhibited the best corrosion resistance, attributed to the effect of the oxide film and (Mg,Al)2Ca phases which were discontinuously distributed on the grain boundaries. These phases acted as micro-victims, they preferentially corroded to protect the α-Mg matrix. The oxide film formed on the alloy surface can hinder the solution further to protect the α-Mg matrix.

Utilization of automotive shredder residues in a thermal process for recovery of manganese and zinc from zinc–carbon and alkaline spent batteries

The aim of the study is the recovery by thermal treatment of manganese and zinc from a mixture of zinc–carbon and alkaline spent batteries, on the basis of the different phase change temperatures of the two metal-bearing phases. ASR (Automotive Shredder Residue), containing 68% of carbon, was added to the mixture to act as a reductant to metallic Zn of the zinc-bearing phases. The mixture was subsequently heated in different atmospheres (air, CO2 and N2) and at different temperatures (900°C, 1000°C and 1200°C) and stoichiometric excess of ASR (300%, 600% and 900%). Characterization of the mixture and of the residues of thermal treatment was carried out by chemical analysis, TGA/DTA, SEM and XRD. The results show that recovery of 99% of zinc (grade 97%) is achieved at 1000°C in N2 with a stoichiometric excess of car-fluff of 900%. This product could be suitable for production of new batteries after refining by hydrometallurgical way. Recovery of Mn around 98% in the residue of the treatment is achieved at any temperature and atmosphere tested with a grade of 57% at 900% excess of car-fluff. This residue is enriched in manganese oxide and could be used in the production of iron–manganese alloys.