Addition Of Mn Research Articles

Ruminal Solubility and Bioavailability of Inorganic Trace Mineral Sources and Effects on Fermentation Activity Measured in Vitro

The aim of this study was to assess the effects of supplementation with inorganic sources of manganese (MnO, MnSO4), zinc (ZnO, ZnSO4) and copper (CuSO4) at different levels (0.06%DM for Mn, 0.05%DM for Zn; 0.01 and 0.05%DM for Cu) on in vitro rumen fermentation, solubility and bioavailability. Fermentation activity was measured by total gas production (TGP) and dry matter degradability after 70 h of fermentation (dDM%). Trace mineral (TM) solubility was estimated via the TM concentration in the supernatant of the final fermentation medium (SOL) and TM bioavailability from the TM concentration in a bacterial-enriched fraction (BACT). Mn (regardless of source) and ZnO tended (p < 0.10) to decrease, while Cu showed no significant effect on TGP. The addition of inorganic Mn and of ZnO tended (p < 0.10) to decrease, ZnSO4 tended to increase (p < 0.10), whilst Cu showed no effect on dDM%. Concerning solubility, Mn (MnO and MnSO4), ZnSO4 and CuSO4 significantly (p < 0.05, p < 0.001 and p < 0.01) increased, while ZnO did not affect TM content in the SOL. These results indicate that MnSO4, ZnSO4 and CuSO4 are highly soluble, MnO is quite soluble, while ZnO has a low solubility in the rumen. Based on the TM content in BACT, MnO, MnS4 and CuSO4 have high bioavailability, while ZnO is poorly assimilated by rumen bacteria. However, the lack of clear inhibition or improvement in fermentations suggests that the rumen microbiota have a low requirement for TM supplementation.

The effect of minor addition of Mn in AA7075 Al–Zn–Mg–Cu aluminum alloys on microstructural evolution and mechanical properties in warm forming and paint baking processes

The microstructures and mechanical properties in the peak ageing condition, warm forming process, and paint baking process of two Al–Zn–Mg–Cu aluminum alloys, which possessed the same base compositions but different levels of Mn (0 and 0.24 wt%), have been investigated. The results show that Mn addition can hardly refine the grain size (around 20 μm) in AA7075 aluminum alloy in warm forming and paint baking processes. Mn-free and Mn-containing alloys subjected to all three processes possess nano-precipitates of nearly the same size, indicating that Mn addition does not influence the nano-precipitate evolution in the aluminum matrix. Energy-dispersive X-ray spectroscopy (EDS) mapping results of dispersoids show that dispersoids in Mn-bearing specimens are enriched in Mn and depleted in Zn and Mg. The Zn and Mg expelled from dispersoids in Mn-containing specimens into the aluminum matrix presumably formed Zn- and Mg-rich zones around the dispersoids, which improved the precipitate transformation reation from GPII to η′ phase at the boundaries between aluminum matrix and dispersoids. Although the solid solution strengthening effect triggered by Mn addition might be less effective because of the formation of dispersoids, the slight enhancement of ultimate tensile strength (UTS) in Mn-containing specimens rather than in Mn-free specimens in all states can be attributed to the formation of nano-precipitates around the dispersoids.

Study on the mechanism of dilute Mn addition in enhancing the creep resistance of hot-rolled Mg-1.5Y alloy sheet

In this work, the compressive creep behaviors of Mg-1.5 wt%Y (0Mn alloy) and Mg-1.5 wt%Y-1wt.%Mn (1Mn alloy) were investigated. The compressive creep tests were performed along the rolling direction (RD), transverse direction (TD) and normal direction (ND) at 523 K under applied stresses ranging from 30 MPa to 80 MPa. It was shown that the 1Mn alloy exhibited a much higher creep resistance than the 0Mn alloy when crept along the same direction. The microstructure characterization indicated that the addition of dilute Mn barely changed the creep mechanisms crept along the RD and TD, including the dislocation cross-slip composed of basal <a > dislocations and prismatic <a > dislocations and {101‾2} twinning in both alloys. While the creep mechanisms crept along the ND changed from dislocation climb and pyramidal <c + a > slip in the 0Mn alloy to dislocation cross-slip and pyramidal <c + a > slip in the 1Mn alloy. The creep resistance enhancement by dilute Mn addition was closely related to the dynamic precipitation of α-Mn particles that strongly hindered the mobilities of dislocations and grain boundaries regardless of the loading direction. Moreover, the Mn atoms tended to segregate on the dislocations during creep, which effectively suppressed the continuous movement of dislocations and led to the excellent creep resistance of the 1Mn alloy. With increasing applied stress, the increased twin amounts crept along the RD and TD were responsible for the strong creep anisotropy in both alloys. Nevertheless, the dynamic precipitation of α-Mn particles evidently inhibited the thickening of twins, which was beneficial for the enhanced creep resistance and decreased creep anisotropy in the 1Mn alloy.

Effects of Sn and Mn Addition on the Microstructure and Mechanical Properties of As-Extruded Mg–2Al–1Zn Alloys

Effects of Sn and Mn Addition on the Microstructure and Mechanical Properties of As-Extruded Mg–2Al–1Zn Alloys

Microstructural evolution of worn surface and subsurface of high Mn additive iron-based hardfacings subjected to repetitive impacts and sliding

In this article, a new impact-sliding wear test setup was developed to investigate the impact-sliding tribological/wear behavior of manganese (Mn) additive iron-based hardfacings. The effect of increased Mn content from 0 to 13 wt% on the wear characteristics was examined for a constant load of 200 N, 1000 impacts and 50 strokes/min speed. Hardness evaluation tests revealed that the hardness was increased after the impact-sliding wear tests. The worn surfaces of hardfacings/alloys/hardfacing alloys containing 0 and 8 wt% Mn presented a similar mechanism of micro-abrasion, but the damage caused by the abrasion in 8 wt% Mn additive hardfacings was not so effective in comparison to the hardfacing containing 0 wt% Mn. Above 8 wt% Mn addition, oxidative wear became the dominant wear mechanism with the formation of protective tribo-oxide layers and the wear trend exhibited enhancement in the wear resistance of hardfacings. On the other hand, subsurface analysis showed severe damage under the tribo-oxide layer, which revealed that the wear trend is not an exact indicator of wear resistance of the material. Wear behavior of the hardfacings has been successfully correlated with the hardness, morphology of the worn surfaces and subsurfaces.

Graphene Quantum Dots Derived from Honey and Mangostin as Sustainable Materials to Construct Fluorescence Turn‐On Molecular Switches for Pesticide Detection

AbstractExtensive use of pesticides in agriculture can lead to environmental pollution and potentially adverse health effects. A fluorescence Turn‐On molecular switch, derived from naturally occurring α‐mangostin (MN), isolated from the pericarp of mangosteen fruit and Graphene Quantum Dots (GQDs) synthesized from honey, was developed for the detection of carbofuran‐an organic toxic carbamate pesticide. GQDs derived from honey shows a strong fluorescence emission centered at 430 nm, which was efficiently quenched by the addition of MN. The quenching of fluorescence of GQDs by the addition of MN (OFF state) and the regaining of quenched fluorescence of GQDs‐MN system (ON state) upon the addition of the pesticide carbofuran was utilized as a detection strategy for the toxic pesticide carbofuran.

Surprising cocktail effect in high entropy alloys on catalyzing magnesium hydride for solid-state hydrogen storage

Magnesium hydride (MgH2) attracts wide interests as a promising hydrogen energy carrier, but its commercial application is hampered by the high operating temperatures and slow dehydrogenation kinetics. Herein, CrMnFeCoNi and CrFeCoNi high-entropy alloys (HEAs) were adopted to boost the hydrogen storage performance of MgH2. It was demonstrated that the morphology of catalysts and addition of Mn had a great impact on the performance of HEAs catalysts. In particular, the Mn containing HEAs nanosheets presented the best performance. The MgH2-CrMnFeCoNi composite could release 6.5 wt% H2 in 10 min at 300 °C and started to absorb H2 at 40 °C. Moreover, kinetic analysis revealed that the rate control model in dehydrogenation process of HEA-4 modified MgH2 changed from permeation model of MgH2 to diffusion. In addition, 97% hydrogen storage volume could be maintained after 20 cycles at 300 °C, showing a good cycling performance. Microstructure analysis showed that the CrMnFeCoNi nanosheets were uniform dispersed over the surface of MgH2, bringing numerous heterogeneous activation sites to speed up the dispersal of hydrogen. Besides, the cocktail effect of HEAs exerted synergic action between Cr, Mn, Fe, Co and Ni elements to improve the overall catalytic efficiency. Therefore, the de/rehydrogeantion performance of the MgH2-CrMnFeCoNi composite was surprisingly accelerated.

Role of KMnO&lt;sub&gt;4&lt;/sub&gt;–NaF Treatment in Galvanic Corrosion Resistance of AA5083 Coupled to Steel

The role of KMnO4–NaF conversion treatment in the galvanic corrosion resistance of AA5083 aluminum alloy coupled to AISI 1045 carbon steel in synthetic seawater (diluted 100 times) was investigated. The 10 min-treated AA5083 was observed to reduce the period of high current density during the early stage of coupling and decrease the number of localized corrosion damages on the AA5083. The 10 min conversion treatment significantly reduced the electrode potential of bulk Al6(Fe, Mn), and it was concluded that the Al6(Fe, Mn) particles on the conversion-treated AA5083 no longer acted as a local cathode at the electrode potential when the AA5083 was in contact with AISI 1045 carbon steel. The decrease in cathodic activity of Al6(Fe, Mn) was attributed to the removal of Fe from the surface film of Al6(Fe, Mn), addition of Mn by the conversion treatment, and thickening of the film.

Influence of solution-hardening on the mechanical properties and wear resistance of copper alloys

Solid-solution hardening can increase the wear resistance of metals, involving two factors: the solute 1) pins dislocations, leading to increased hardness of the metals; 2) influences the atomic bond strength and thus Young's modulus, which also affects the resistance to dislocation generation and movement. Solute atoms generally increase hardness of the host metal but may increase or decrease its Young's modulus, which is related to the solute's electron work function (EWF). In this study, Cu (EWF = 4.65 eV) was hardened by solutes, Ni (EWF = 5.15 eV), and Mn (EWF = 4.1 eV), respectively. CuNi (10, 30, 60, 80 wt% Ni) and CuMn (2, 4, 6, 8 wt% Mn) alloys were prepared using an arc furnace. It is demonstrated that with Ni addition, both hardness and Young's modulus increased, while Mn addition led to a decrease in Young's modulus though the hardness was increased. As a result, the effect of Ni on the wear resistance of Cu is underestimated when predicted using the classic Archard equation, while that of Mn is overestimated. Such an issue of under- or over-estimation can be corrected using a wearing energy model, which takes into account the influence of Young's modulus on the wear resistance. The wearing energy model is a modified form of Archard equation, established by including wearing energy consumption via the relationships among atomic bond strength, Young's modulus, and EWF. Density functional theory (DFT) calculations on CuMn and CuNi alloys systems confirm a stronger metallic bond in CuNi with higher overall EWF, compared with that in CuMn showing a lower overall EWF.

Effect of Mn on microstructure and tensile properties of as-cast Al0.5CoFeNiC0.1 high-entropy alloy

The effect of Mn on the microstructure and tensile properties of Al0.5CoFeNiC0.1 HEA (high-entropy alloy) has been investigated using electron microscopy, atom probe and mechanical testing. The results show that addition of Mn refines dendrite and grain and reduces volume fraction of B2 phase and interdendritic regions. Mn is demonstrated to be not the former of κ′ phase. Therefore, the addition of Mn reduces the size and volume fraction of the κ′ phase, leading to a reduction in the yield strength of the HEA whereas an enhancement in ductility. 7.7 at.% Mn doping makes the HEA (Mn0.3) have a good balance between yield strength (1 GPa) and ductility (23% elongation). Adding Mn does not change deformation mechanism of the HEAs.

Effect of Mn Addition to Al–Si Alloy on the Layer Formed at the Interface with Cast Iron in Compound Casting

Effect of Mn Addition to Al–Si Alloy on the Layer Formed at the Interface with Cast Iron in Compound Casting

Investigating the effect of Al, Mo or Mn addition to CoCrFeNi entropy alloys on the interface binding properties of WC/HEA cemented carbides

At present, it is found that the mechanical properties of WC/HEA cemented carbide are mainly affected by the interfacial bonding properties of hard phase and bonding phase. Therefore, the effect of adding Al, Mo or Mn on the interfacial bonding properties of WC/HEA cemented carbides was studied by first-principles simulation. The results show that adding Mn can enhance the interface bonding performance, while adding Al and Mo is the opposite. Compared with Al and Mo atoms, Mn atoms are more likely to form strong bonds with W atoms at WC/HEA cemented carbide interface. In order to verify the rationality of the calculation, WC/HEA cemented carbide samples were prepared by mechanical alloying and gas pressure sintering. It is found that WC/CoCrFeNiMn has the best mechanical properties. Its hardness, fracture toughness and strength are 1562 HV, 9.3 MPa·m1/2, 850 MPa. The experimental results further confirm that adding Mn can improve the interfacial bonding properties of WC/HEA cemented carbide.

Enhanced long-term thermal stability and mechanical properties of twin-roll cast Al–Mg–Si alloys with Mn and Cu additions

The long-term thermal stability of Al–Mg–Si alloy is of great significance for its engineering application. In this work, the effects of Mn and Cu on the microstructure and mechanical properties of the twin-roll cast (TRC) AA6005 alloy after peak aging and long-term thermal exposure were studied. The results show that the addition of Mn introduces Al(FeMn)Si dispersoids, which improves the mechanical properties of the alloy under the peak aging condition by dispersion strengthening. After thermal exposure at 150 °C for 1000 h, the Al(FeMn)Si dispersoids have good thermal stability while do not significantly improve the mechanical properties. The reason may be related to the decreased number density of the β″ phase after alloying with Mn. The addition of Cu changes the aging precipitation sequence, and the needle-like pre-Q′ phase is formed during artificial aging. Moreover, due to the low diffusion rate of Cu in the Al matrix, Cu atoms can better stabilize the structure and then improve the coarsening resistance of the precipitates, and therefore the Cu-containing precipitates exhibit better thermal stability than the β″ phase. After thermal exposure at 150 °C for 1000 h, the yield strength of the 0.5Cu alloy decreases by only ∼12 MPa (from ∼295 to ∼283 MPa), which is significantly lower than that of the AA6005 alloy (∼41 MPa, from ∼274 to ∼233 MPa). The yield strength of the 0.25Mn0.25Cu alloy decreases by ∼27 MPa (from ∼294 to ∼267 MPa) and is more suitable for industrial production as its composition is within the range of commercial 6xxx aluminum alloys. The results would provide a strategy for the preparation of Al–Mg–Si alloys with high thermal stability.

Influence of Zinc, Iron and Manganese Applications on Soil Properties, Protein Content and Sedimentation Value of Wheat

Micronutrient insufficiency in plants is becoming increasingly common, particularly in cereals crops around the world. These deficits result in a loss of yield as well as deterioration in the nutritional quality of the crops. The experiment was carried out in screen house for Rabi season of 2017-18, Soil Science Department, CCS HAU, Hisar to measure the impact of methods and dosages of zinc (Zn), iron (Fe) and manganese (Mn) application on post-harvest soil characteristics and wheat quality. The findings of this research illustrated that DTPA-extractable Zn and Mn increased significantly with the addition of Zn and Mn, respectively as compared to control. With the application of micronutrients, the sedimentation value and protein content of wheat both significantly increased in comparison to the control. Maximum increase in sedimentation value (54.0) was found when 0.5 % ZnSO4 + 2.5 % urea was applied. Whereas, maximum increase in protein content (12.2%) was observed when 0.5 % FeSO4 + 3 % urea was applied. Overall, quality of wheat improved with the application of micronutrients but there was no significant effect of these applications on soil parameters. There was no significant variation in soil pH, soil organic carbon (SOC), electrical conductivity (EC), available nitrogen (N), phosphorus (P), potassium (K) and DTPA-extractable Fe when micronutrients were applied as foliar or basal doses.

Ni3S4 nanoparticle decorated Mn doped Co(OH)2 nanosheets as electrodes of hybrid supercapacitors with high energy density and long-term cycle stability

Due to their outstanding electrochemical properties, transition metal sulfides and hydroxides are often used as high-performance electrode materials for supercapacitors. The Mn-doped Co(OH)2/Ni3S4 electrode material in this study, due to the synergistic reaction mechanism among Co(OH)2 and Ni3S4 and the increased active sites by the addition of Mn, the Mn-Co(OH)2/Ni3S4 exhibits excellent electrochemical property. The electrochemical performance of the Mn-Co(OH)2/Ni3S4 hybrid electrode was measured in an electrode cell made of 2 M KOH solution, showing a superior specific capacitance of 1107.0 C g−1 at 0.5 A g−1, in addition to the excellent capacity retention rate at 10 A g−1 is 72.7 % of that at 1 A g−1. The performance of the hybrid supercapacitor (HSC) assembled with Mn-Co(OH)2/Ni3S4 compound and activated carbon (AC) was measured under the same electrolyte conditions, anwell-specificific capacity (157.2 F g−1 at 0.5 A g−1) was achieved, along with superior long-term stable charge/discharge capability (88.9 % of the original specific capacity after 35,000 cycles at 8 A g−1). Meanwhile, the most practical application is when the power density of 410.4 W kg−1, the assembled HSC device has an energy storage capacity of 58.8 W h kg−1, revealing that the developed Mn-Co(OH)2/Ni3S4 has great application potential for supercapacitors in the future.

Experimental and computational study on the C15 phase structure stability of YzNi2-yMny system

Y0.95Ni2 intermetallic is a promising candidate for hydrogen storage applications, but currently suffers from hydrogen-induced amorphization (HIA) mainly caused by its low stability. The structure stability of AB2 Laves phase is mainly controlled by the geometric factor rA/rB. The present work is focused on the ternary Mn-Ni-Y system, as Mn addition helps achieving a close-to-ideal rA/rB (≤1.37) to avoid HIA or HID. Through a combination of X-ray diffraction, neutron diffraction, electron probe micro-analysis and first-principles calculations, new insight on the physicochemical properties and phase equilibrium of this ternary system was gained. Mn substitution is found to suppress the formation of a super-structure with ordered vacancies, in favor of a C15 Laves structure with a disordered distribution of Y vacancies. At low concentration Mn is accommodated only on the Ni sites, compensated by vacancies on the Y site (without long-range order). At high concentration, Mn is accommodated on both Ni and Y sites, with reduced Y vacancy concentration. The partitioning of Mn across the two sites allows to form a single-phase ternary intermetallic across a wide compositional range and suggests increased stability of the phase.

Hydrogen Embrittlement and its Prevention in 7XXX Aluminum Alloys with High Zn Concentrations

7xxx aluminum alloys are representative high-strength aluminum alloys; however, mechanical property degradation due to hydrogen hinders further strengthening. We have previously reported that hydrogen embrittlement in 7xxx alloys originates from trapped hydrogen at the MgZn2 precipitate interface, providing high hydrogen trapping energy. We propose the dispersion of Mn-based second-phase particles as a novel technique for preventing 7xxx aluminum alloy hydrogen embrittlement. In this study, the deformation and fracture behaviors of high hydrogen 7xxx alloys containing 0.0% Mn and 0.6% Mn are observed in situ using synchrotron radiation x-ray tomography. Although no significant differences appear between the two alloys regarding the initiation of quasicleavage cracks, the area fractions of final quasicleavage fractures are 16.5% and 1.0% for 0.0% Mn and 0.6% Mn alloys, respectively; this finding indicates that Mn addition reduces hydrogen-induced fractures. The obtained macroscopic hydrogen embrittlement is quantitatively analyzed based on hydrogen partitioning in alloys. Adding 0.6% Mn, generating second-phase particles with high hydrogen trapping abilities, significantly suppresses hydrogen-induced quasicleavage fracture. The results of an original hydrogen partitioning analysis show that the dispersion of Mn-based particles (Al12Mn3Si) with high hydrogen trapping abilities reduces the hydrogen concentration at the semicoherent MgZn2 interface and suppresses hydrogen embrittlement.

Development of high strength-ductility Mg-Er extruded alloys by micro-alloying with Mn

This work systematically investigated the influence of the micro-Mn addition on the microstructures and mechanical properties of Mg-Er alloys. To investigate their deformation mechanisms during tensile testing, electron back-scattered diffraction, transmission electron microscopy, slip trace analysis, and visco-plastic self-consistent polycrystal constitutive (VPSC) modeling were used. The study showed that the as-solid solution samples only consist of the α-Mg phase. All samples exhibit a complete dynamic recrystallized (DRXed) microstructure with an average grain size of 2.79 µm after hot extrusion. The ductility first increases from 26.02 % to 35.34 % and then remains unchanged with the increment of Mn content. Meanwhile, the yield strength significantly increases from 95 MPa to 200 MPa. According to VPSC results, the initial slip resistance (τ0) difference between prismatic and basal slips decreases from 109 MPa to 92 MPa and τ0 between pyramidal and basal slip systems from 129 MPa to 112 MPa. Both the VPSC and two-beam diffraction results confirmed that pyramidal<c+a>slip and<a>slip were activated during tensile deformation. The quantitative analysis of the slip trace line verified that the volume of non-basal slip reached 65 % when the content of Mn was increased to 0.9 wt%. Mn in solid solution increased the activity of pyramidal<c+a>and prismatic<a>dislocations during deformation, which is beneficial for accommodating c-axis strain. Consequently, the ambient ductility of Mg-2Er alloy with Mn addition is improved.

Synergistic effects of Mn and B on iron-rich intermetallic modification of recycled Al alloy

Individual manganese (Mn) modification cannot prevent the formation of coarse and blocky Iron-rich phases in recycled Al–Si alloys. In the present work, scanning/transmission electron microscopy (SEM/TEM), thermodynamic calculations, and synchrotron X-ray imaging were comprehensively applied to reveal the synergistic effect of Mn and B (boron) on Iron-rich phase formation in Al–Si–Fe alloys during solidification. The results showed that with addition of Mn and B, the morphology of Iron-rich phase translated from the coarse primary into a uniform and hollow-shaped multibranched Chinese-script morphology. An appropriate boron amount significantly reduced the initial nucleation temperature of the primary Iron-rich phase and increased the number of nucleation cites. The TEM results show that there was no obvious orientations relationship between the AlB2 and α-Al15(MnFe)3Si2 phases. The main modification mechanism is that B was adsorbed on the oxide film surface, which hindered the formation of the Iron-rich phase at high temperature. This Mn + B compound modification method provides an alternative way to enhance the mechanical properties of recycled Al–Si alloys in industry.

Effect of alloying elements on mechanical behaviour of Cu-Zn-Sn bronzes

Abstract The effect of Fe, P and Mn on microstructure and fatigue properties of CuZnSn bronzes investigated with optical microscopy and scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, hardness, tensile and fatigue tests. The addition of Fe, Mn and P to Cu-Zn-Sn bronzes formed Cu31Sn8, Cu6Sn5, ZnSn2, PbSnS2, ZnS, Cu2S, FeZn9 and FeZn21 phases. These phases were deposited between the dendrite arms and were dissolved in the matrix in small amounts. Especially, these precipitated phases were effective in fatigue properties. The formation of Cu-Sn, Cu-Zn and Zn-Sn intermetallic phases emitted due to the addition of Fe, Mn and P increased the fatigue strength. The spread of ferrous phases caused an increase in mechanical properties. The beneficial effect of P addition on the fatigue life far surpassed that of Mn and Fe additives.