Developing high yield strength and ductility in low–cost Mg alloys using conventional plastic forming process is a tremendous challenge. Mg–Mn–based alloys have drawn considerable attention owing to ...their low–cost, high ductility and good corrosion resistance. However, the strength of Mg–Mn binary alloy is not satisfactory for industrial scale applications. In the present study, low content of Al alloying in Mg–1Mn alloy is the aim to obtain high strength and ductility of Mg–Mn–based alloys with low cost. Experimental results revealed that phase composition of the targeted Mg–1Mn–xAl (x = 0.3 wt%, 0.5 wt%, 1.0 wt%) alloys were composed of α-Mn + Al8Mn5, Al8Mn5 and Al8Mn5+Al11Mn4 phase, respectively. Al–Mn particles significantly refined the dynamically recrystallized (DRXed) grains. Among them, Al8Mn5 particles exhibited the most effective grain refinement. Therefore, Mg–1Mn–0.5Al alloy containing single-phase Al8Mn5 particles possessed the finest microstructure and exhibited the best mechanical properties. The high performance of the alloy was mainly attributed to the fine DRXed grains according to the Hall–Petch effect and to the large amount of fine Al8Mn5 particles through the dispersion strengthening. Meanwhile, the weak texture of fine grains enhanced the ductility. The fine DRXed grains and numerous Al8Mn5 particles effectively suppressed the extension twining, thus substantially enhanced the compression yield strength, and resulted in improved anisotropy.
A new strategy for the determination of metal impurities in magnesium
(Mg(TFSI)
) electrolytes for rechargeable magnesium batteries using inductively coupled plasma tandem mass spectrometry ...(ICP-MS/MS) was proposed. Mg(TFSI)
was dissolved in 1,2-dimethoxyethane (DME), and 13 metal impurity elements were directly determined. Since N
has a lower O atom affinity (1.6 eV) than the O atom (5.2 eV), N
O was a more effective O atom transfer gas than O
. In the MS/MS mode, N
O was selected as the reaction gas, and high sensitivities and low limits of detection (LODs) of analytes were obtained by mass shift methods. The accuracy of proposed analytical methods was assessed by the spike recovery experiments and comparative analyses using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). LODs were in the range of 0.18-26.6 ng kg
, the recoveries were 92.5%-107%, and the relative standard deviation (RSD) was 2.0%-5.3%. No significant difference was observed between the ICP-MS/MS and SF-ICP-MS results at a 95% confidence level. The measurement realized the rapid determination of 13 metal impurity elements in Mg(TFSI)
using N
O as a reaction gas with high sensitivity, accuracy, and precision. The method was applied for the analysis of Mg(TFSI)
products with satisfactory results.
A new strategy for the determination of metal impurities in magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) electrolytes for rechargeable magnesium batteries using inductively coupled ...plasma tandem mass spectrometry (ICP-MS/MS) was proposed. Mg(TFSI)2 was dissolved in 1,2-dimethoxyethane (DME), and 13 metal impurity elements were directly determined. Since N2 has a lower O atom affinity (1.6 eV) than the O atom (5.2 eV), N2O was a more effective O atom transfer gas than O2. In the MS/MS mode, N2O was selected as the reaction gas, and high sensitivities and low limits of detection (LODs) of analytes were obtained by mass shift methods. The accuracy of proposed analytical methods was assessed by the spike recovery experiments and comparative analyses using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). LODs were in the range of 0.18–26.6 ng kg–1, the recoveries were 92.5%–107%, and the relative standard deviation (RSD) was 2.0%–5.3%. No significant difference was observed between the ICP-MS/MS and SF-ICP-MS results at a 95% confidence level. The measurement realized the rapid determination of 13 metal impurity elements in Mg(TFSI)2 using N2O as a reaction gas with high sensitivity, accuracy, and precision. The method was applied for the analysis of Mg(TFSI)2 products with satisfactory results.
A magnesium-aluminum layered-double-hydroxides (MgAl LDHs) coating was fabricated on the surface of Mg alloy AZ31, followed by electrophoretic deposition of an Al2O3 nanoparticles layer. The ...morphology, structure and composition of the composite coatings were investigated by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and energy dispersive spectrometry (EDS). Ball on disc tests were carried out for measurements of the friction coefficient, wear loss and morphology of worn surfaces. Corrosion behavior of the coatings was investigated using potentiodynamic polarization curves and electrochemical impedance spectroscopy. Results indicate that the LDHs/Al2O3 composite coatings fabricated with 2.5 g/L Al2O3 nanoparticles solution exhibited best wear resistance, while best corrosion resistance was associated with the composite coating fabricated with 0.5 g/L Al2O3 nanoparticle solution. A sound mechanism for improving wear-resistance of the resulting coatings was proposed.
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•The voids between LDHs nano-sheets are employed as “containers” to accommodate wear-resistant Al2O3 nanoparticles.•LDHs coating and Al2O3 nanoparticles had a synergistic effect on anti-wear and anti- corrosion performance.•Composite coatings with 2.5 g/L nanoparticles showed best wear resistance, and best corrosion resistance was with 0.5 g/L.
Mechanical properties and microstructures of AZ31 magnesium alloys containing different impurity levels but having the same alloying element content, were investigated at ambient temperature. These ...AZ31 alloys were produced by semi-continuous casting, wherein the content of impurity was varied systematically. Microstructure observation shows that finer grains are existent in the alloy with lower impurity level. Tensile testing reveals that a reduction of impurity content results in a noticeable increase of the strength and elongation in the alloys in the cast, homogenized and extruded states. As the impurity content decreases from 0.0462wt% to 0.0163wt%, the ultimate tensile strength is evidently enhanced by 62 MPa and the elongation is nearly doubled in the homogenized specimen. The observed property improvement was discussed in terms of the microstructure variation with impurity reduction.
Improving the anticorrosion property of Mg alloys used as concrete formwork is essential for extending their lifespan and ensuring structural integrity. Therefore, MgCO3·3H2O + MgCO3·Mg(OH)2·3H2O/MgO ...composite coating was prepared on AZ41 Mg alloys using an ultrasonic-cavitated chemical conversion method under different pH conditions. Electrochemical methods combined with immersion tests in the simulated concrete pore solutions containing 0.6 M NaCl were adopted to assess the anticorrosion performance of the uncoated and coated specimens. Results indicate that the improved pH benefits the densification of the composite coating, thus leading to the enhanced anticorrosion performance. The generation of dense MgCO3·Mg(OH)2·3H2O layer rather than corrosion products after immersion makes such an affordable anticorrosion coating, amenable to large-scale production, holds promise as a viable surface treatment method for Mg alloy concrete formwork.
A convenient method named wet coordination is used to prepare the sample or carbon-coated Li3V2(PO4)3 in the furnace with a flowing argon atmosphere at 600aaA degree C for 1aah. The sample is ...characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and energy dispersive analysis of X-rays (EDAX). Galvanostatic charge-discharge between 3.3 and 4.3aaV (vs. Li/Li+) shows that the sample exhibits a high discharge capacity of 128aamAhaaga degree 1 with a good reversible performance under a current density of 95aamAaaga degree 1. It suggests that carbon-coated Li3V2(PO4)3 with good electrochemical performance can be obtained via this method, which is suitable for large-scale production. Display Omitted
A novel LPSO containing Mg-5Y-2n-2Li-0.5Al alloy with superior mechanical behaviors and damping capacities was first developed in this paper. The microstructure evolution, mechanical and damping ...properties of Mg-5Y-2n-2Li-0.5Al alloy were analyzed and compared with those of Mg-5Y-2Zn-2Li alloy. The results indicated the extruded Mg-5Y-2n-2Li-0.5Al alloy exhibited bimodal grain structure, including fine dynamically recrystallized grains (DRXed grains) and coarse un-dynamically recrystallized (unDRXed) grains, accompanied by the produce of the 14H LPSO phase, Al3(Y, Zn) particle and nano-precipitates AlLi phase. Due to the strengthening effects of grain boundary, residual dislocation and precipitation, the ultimate tensile strength (UTS), tension yield strength (TYS) and elongation (EL) of the extruded Mg-5Y-2Zn-2Li-0.5Al alloy were 312 MPa, 229 MPa and 10.9%, respectively, which were higher than that those of the extruded Mg-5Y-2Zn-2Li alloy. In addition, the extruded Mg-5Y-2Zn-2Li-0.5Al alloy displayed good damping capacities at both room and high temperature (RT and HT), and its RT damping value (Q−1) at 5 × 10−4 strain amplitude exceeded 0.01, which associated with a high density of movable dislocation. With rising the temperature, the extruded Mg-5Y-2n-2Li-0.5Al alloy possessed superior damping properties than the Al-free alloy, which derived from the grain boundary slide (GBS) and the activation of the incoherent interface between the Al3(Y, Zn) and α-Mg phase after adding Al element.
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•The addition of trace Al element significantly changed the microstructure of the Mg-5Y-2Zn-2Li alloy.•The mechanical properties and damping capacities were simultaneously improved in the extruded Mg-5Y-2n-2Li-0.5Al alloy.•It was a major breakthrough in balancing the relationship between strength and damping of Mg alloys.
Multiwalled carbon nanotubes (MWCNT) decorated by magnetite (Fe3O4) nanoparticles were incorporated into sodium alginate (SA) to fabricate SA–Fe3O4@CNT hybrid membranes. The Fe3O4 nanoparticles were ...strongly attached onto the MWCNT surface and served as steric barrier to suppress the agglomeration of the MWCNT and improve their dispersion in the hybrid membranes. The synergistic effect of combining Fe3O4 and MWCNT led to both decreasing the membrane crystallinity as well as providing fast-moving micro-channels. After depositing the hybrid membrane (as the active layer) onto the polyacrylonitrile porous support layer, the new composite membranes exhibited excellent separation performance for ethanol dehydration. Using 2wt% Fe3O4@CNT as nanofiller, the membrane permeation flux for dehydration of 10wt% water ethanol feed solution reached as high as 2211g/m2h with separation factor of 1870 at 76°C.
•Hydrophilic Fe3O4 were decorated on CNTs by in situ co-precipitation.•An improved dispersion of Fe3O4@CNT within the membranes was achieved.•Favorable transport properties were achieved by coexistence of Fe3O4 and CNTs.•Hybrid membranes showed high water permeability and separation selectivity.
