This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period ...This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the focus.The morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered network.After heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R structure.As Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloy.Both Zn and the heat treatment had a significant effect on damping.Obvious dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys.After heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).66.The annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom content.These factors also affected the dynamic modulus of the alloy.The results of this study will help in further development of high-damping magnesium alloys.展开更多
Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategie...Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategies have been devised to enhance the Mg^(2+)migration kinetics and structural stability of cathodes,they fail to improve electronic conductivity,rendering the cathodes incompatible with magnesium-metal anodes.Herein,we propose a dual-defect engineering strategy,namely,the incorporation of Mg^(2+)pre-intercalation defect(P-Mgd)and oxygen defect(Od),to simultaneously improve the Mg^(2+)migration kinetics,structural stability,and electronic conductivity of the cathodes of RMMBs.Using lamellar V_(2)O_(5)·nH_(2)O as a demo cathode material,we prepare a cathode comprising Mg_(0.07)V_(2)O_(5)·1.4H_(2)O nanobelts composited with reduced graphene oxide(MVOH/rGO)with P-Mgd and Od.The Od enlarges interlayer spacing,accelerates Mg^(2+)migration kinetics,and prevents structural collapse,while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity.Consequently,the MVOH/rGO cathode exhibits a high capacity of 197 mAh g^(−1),and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g^(−1),capable of powering a light-emitting diode.The proposed dual-defect engineering strategy provides new insights into developing high-durability,high-capacity cathodes,advancing the practical application of RMMBs,and other new secondary batteries.展开更多
Rechargeable magnesium batteries(RMBs),as a low-cost,high-safety and high-energy storage technology,have attracted tremendous attention in large-scale energy storage applications.However,the key anode/electrolyte inte...Rechargeable magnesium batteries(RMBs),as a low-cost,high-safety and high-energy storage technology,have attracted tremendous attention in large-scale energy storage applications.However,the key anode/electrolyte interfacial issues,including surface passivation,uneven Mg plating/stripping,and pulverization after cycling still result in a large overpotential,short cycling life,poor power density,and possible safety hazards of cells,severely impeding the commercial development of RMBs.In this review,a concise overview of recently advanced strategies to address these anode/electroyte interfacial issues is systematically classified and summarized.The design of magnesiophilic substrates,construction of artificial SEI layers,and modification of electrolyte are important and effective strategies to improve the uniformity/kinetics of Mg plating/stripping and achieve the stable anode/electrolyte interface.The key opportunities and challenges in this field are advisedly put forward,and the insights into future directions for stabilizing Mg metal anodes and the anode/electrolyte interface are highlighted.This review provides important references fordeveloping the high-performance and high-safety RMBs.展开更多
Rechargeable Mg batteries(RMBs)have become one of the best subsitutes for lithium-ion batteries due to the high volumetric capacity,abundant resources,and uniform plating behavior of Mg metal anode.However,the safety ...Rechargeable Mg batteries(RMBs)have become one of the best subsitutes for lithium-ion batteries due to the high volumetric capacity,abundant resources,and uniform plating behavior of Mg metal anode.However,the safety hazard induced by the formation of high-modulue Mg dendrites under a high current density(10 mA cm^(-1))was still revealed in recent years.It has forced researchers to re-examine the safety of RMBs.In this review,the intrinsic safety factors of key components in RMBs,such as uneven plating,pitting and flammability of Mg anode,heat release and crystalline water decomposition of cathode,strong corrosion,low oxidition stability and flammability of electrolytes,and soforth,are systematacially summarized.Their origins,formation mechanisms,and possible safety hazards are deeply discussed.To develop high-performance Mg anode,current strategies including designing artificial SEI,three-dimensional substrates,and Mg alloys are summarized.For practical electrolytes,the configurations of boron-centered anions and simple Mg salts and the functionalized solvent with high boiling point and low flammability are suggested to comprehensively design.In addition,the future study should more focus on the investigation on the thermal runaway and decomposition of cathode materials and separa-tors.This review aims to provide fundamental insights into the relationship between electrochemistry and safety,further promoting the sustainable development of RMBs.展开更多
In this study,Mg-13.2Gd-4.3Ni alloys containing continuous bulk-shaped long-period stacking ordered(LPSO),lamellar LPSO,and a small amount of eutectic phase were prepared,and the evolution of microstructure at differe...In this study,Mg-13.2Gd-4.3Ni alloys containing continuous bulk-shaped long-period stacking ordered(LPSO),lamellar LPSO,and a small amount of eutectic phase were prepared,and the evolution of microstructure at different extrusion temperatures and its influence on mechanical and degradation properties as well as corrosion mechanism were investigated.Preheating before extrusion can effectively promote the precipitation of lamellar LPSO in matrix.EX400 with higher volume fraction of non-DRXed grains exhibited higher strength,which was mainly due to strong texture,high dislocation density,and high volume fraction of lamellar LPSO.The EX420 with higher volume fraction of DRXed grains showed higher degradation rate,which was mainly due to the higher density of grain boundary.The EX400 exhibited excellent comprehensive properties with tensile yield strength(TYS)of 334 MPa,ultimate tensile strength(UTS)of 484 MPa and elongation(EL)of 7.4%,ultimate compressive strength(UCS)of 638 MPa and compressive yield strength(CYS)of 443 MPa,degradation rate of 86.1 mg/cm^(2)/h at 93℃in 3 wt.%KCl solution.展开更多
While TiFe alloy has recently attracted attention as the efficient catalyst to enhance de/hydrogenation rates of Mg/MgH_(2),the difficulty of its activation characteristics has hindered further improvement of reaction...While TiFe alloy has recently attracted attention as the efficient catalyst to enhance de/hydrogenation rates of Mg/MgH_(2),the difficulty of its activation characteristics has hindered further improvement of reaction kinetics.Herein,we report that the TiFe_(0.92)Mn_(0.04)Co_(0.04) catalyst can overcome the abovementioned challenges.The synthesized MgH_(2)-30 wt% TiFe_(0.92)Mn_(0.04)Co_(0.04) can release 4.5 wt%of hydrogen in 16 min at 250℃,three times as fast as MgH_(2).The activation energy of dehydrogenation was as low as 84.6 kJ mol^(-1),which is 46.8%reduced from pure MgH_(2).No clear degradation of reaction rates and hydrogen storage capacity was observed for at least 30 cycles.Structural studies reveal that TiFe_(0.92)Mn_(0.04)Co_(0.04) partially decomposes to in-situ generatedα-Fe particles dispersed on TiFe_(0.92)Mn_(0.04)Co_(0.04).The presence ofα-Fe reduces the formation of an oxide layer on TiFe_(0.92)Mn_(0.04)Co_(0.04),enabling the activation processes.At the same time,the hydrogen incorporation capabilities of TiFe_(0.92)Mn_(0.04)Co_(0.04) can provide more hydrogen diffusion paths,which promote hydrogen dissociation and diffusion.These discoveries demonstrate the advanced nature and importance of combining the in-situ generatedα-Fe with TiFe_(0.92)Mn_(0.04)Co_(0.04).It provides a new strategy for designing highly efficient and stable catalysts for Mg-based hydrogen storage materials.展开更多
Magnesium-based energy materials, which combine promising energy-related functional properties with low cost, environmental compatibility and high availability, have been regarded as fascinating candidates for sustain...Magnesium-based energy materials, which combine promising energy-related functional properties with low cost, environmental compatibility and high availability, have been regarded as fascinating candidates for sustainable energy conversion and storage. In this review,we provide a timely summary on the recent progress in three types of important Mg-based energy materials, based on the fundamental strategies of composition and structure engineering. With regard to Mg-based materials for batteries, we systematically review and analyze different material systems, structure regulation strategies as well as the relevant performance in Mg-ion batteries(MIBs) and Mg-air batteries(MABs), covering cathodes, electrolytes, anodes for MIBs, and anodes for MABs;as to Mg-based hydrogen storage materials, we discuss how catalyst adding, composite, alloying and nanostructuring improve the kinetic and thermodynamic properties of de/hydrogenation reactions, and in particular, the impacts of composition and structure modification on hydrogen absorption/dissociation processes and free energy modification mechanism are focused;regarding Mg-based thermoelectric materials, the relations between composition/structure and electrical/thermal transport properties of Mg_(3)X_(2)(X = Sb, Bi), Mg_(2)X(X = Si, Ge, Sn) and Mg Ag Sb-based materials, together with the representative research progress of each material system, are summarized and discussed. Finally, by pointing out remaining challenges and providing possible solutions, this review aims to shed light on the directions and perspectives for practical applications of magnesium-based energy materials in the future.展开更多
Owing to the features(high safety,inexpensive and environmental friendliness)of aqueous rechargeable Mg-ion batteries(ARMIBs),they have drawn extensive attention in the future energy storage systems.However,the poor M...Owing to the features(high safety,inexpensive and environmental friendliness)of aqueous rechargeable Mg-ion batteries(ARMIBs),they have drawn extensive attention in the future energy storage systems.However,the poor Mg^(2+)migration kinetics during the Mg^(2+)intercalation/extraction still hinders the progress of developing suitable cathode materials.Herein,a layered buserite Mg-Mn oxide(MMO)material with large interlayer space(~9.70A)and low-crystalline structure is studied as a high-performance cathode in ARMIBs.Compared with the counterpart,the Mg^(2+)migration kinetics of the MMO cathode can be enhanced by its unique structure(bigger interlayer spacing and low-crystalline structure).The layered buserite MMO as a high-performance ARMIBs cathode exhibits high Mg storage capacity(50 mAg^(-1):169.3 mAh g^(-1)),excellent rate capability(1000 mAg^(-1):98.3 mAh g^(-1)),and fast Mg^(2+)migration(an average diffusion coefficient:~4.21×10-^(10)cm^(2)s^(-1))in 0.5 M MgCl_(2)aqueous electrolyte.Moreover,the MMO-1//AC full battery achieved a high discharge capacity(100 mAg^(-1):111 mAh g^(-1)),and an ignored fading over 5000 cycles(1000 mAg^(-1)).Therefore,layered Mg-Mn oxide with large interlayer space may break a new path to develop the promising ARMIBs.展开更多
Presenilin(Psn)protein is associated with organismal aging.Mutations in the Psn gene may lead to Alzheimer’s disease(AD),dilated cardiomyopathy(DCM),and many age-dependent degenerative diseases.These diseases serious...Presenilin(Psn)protein is associated with organismal aging.Mutations in the Psn gene may lead to Alzheimer’s disease(AD),dilated cardiomyopathy(DCM),and many age-dependent degenerative diseases.These diseases seriously affect the quality of life and longevity of the population and place a huge burden on health care and economic systems around the world.Humans have two types of Psn,presenilin-1(PSEN1)and presenilin-2(PSEN2).Mutations in the genes encoding PSEN1,PSEN2,and amyloid precursor protein(APP)have been identified as the major genetic causes of AD.Psn is a complex gene strongly influenced by genetic and environmental factors.The effects of exercise,training,and a high-fat diet on the Psn gene expressed in the heart and its related pathways are not fully understood.Fortunately,relevant aspects of the mutational effects on Psn can be studied experimentally in easily handled animal models,including Drosophila,mice,and other animals,all of which share orthologous genes of Psn with humans.Many previous studies have linked aging,exercise training,and a high-fat diet to the Psn gene.This review discusses the interrelationship between aging,exercise training,and a high-fat diet on the Psn gene and its associated disease,AD.The aim is to understand the adverse effects of Psn gene mutations on the body and the diseases caused by AD,find ways to alleviate the adverse effects and provide new directions for the improvement of treatment strategies for diseases caused by Psn gene mutations.展开更多
It is recently suggested that air-formed film plays an important role in controlling corrosion resistance of Mg-Li alloys. However, the structure of the air-formed film and its effect on corrosion resistance of Mg-Li ...It is recently suggested that air-formed film plays an important role in controlling corrosion resistance of Mg-Li alloys. However, the structure of the air-formed film and its effect on corrosion resistance of Mg-Li alloys has not been fully understood. Firstly, the air-formed films formed on α and β phases in a dual-phase LZ91 Mg-Li alloy after exposure to laboratory air for up to 48 h have been examined by SEM under the assistance of ultramicrotomy. Then, the effect of the air-formed film on surface potential and, consequently, corrosion/oxidation behavior of the alloy has been investigated. Finally, in order to exclude the influence from α phase, the structure of the air-formed film on β phase and its effect on corrosion/oxidation behavior of Mg-Li alloys have been studied based on a single-phase LA141 Mg-Li alloy. The results show that the air-formed film is thin and negligible on α phase but thick on β phase after prolonged exposure to laboratory air. The thick air-formed film on β phase has a multilayer structure with an inner layer consisting of Mg O/Mg(OH)_(2) and outer layer consisting of Li_(2)CO_(3), which greatly elevates the surface potential of β phase in air. Both LZ91 and LA141 Mg-Li alloys firstly undergo uniform corrosion and then filiform corrosion when immersed in Na Cl solution and the pre-existed air-formed film on β-Li phase can retard the occurrence of filiform corrosion in the alloys.展开更多
In this paper,the effects of different mineral admixtures and sulfate solution types on the appearance,mass change rate,relative dynamic elastic modulus,and corrosion resistance coefficient of concrete were systematic...In this paper,the effects of different mineral admixtures and sulfate solution types on the appearance,mass change rate,relative dynamic elastic modulus,and corrosion resistance coefficient of concrete were systematically studied.X-ray Diffraction(XRD),Mercury Intrusion Porosimetry(MIP),Scanning Electron Microscopy(SEM),and X-ray Computed Tomography(X-CT)were used to explore and analyze the changes in the microstructure and the corrosion products of concrete in the sulfate solution.The results show that the existence of magnesium ions accelerates concrete deterioration.There is a critical dosage of fly ash for magnesium sulfate resistance of concrete.The magnesium sulfate resistance of concrete is improved when the fly ash content is less than 20%.Slag can significantly improve the corrosion resistance of concrete to magnesium sulfate.The diffusion of sulfate ions into concrete is a gradual process.In the early stages of corrosion,sulfate ion content in the concrete immersed in the magnesium sulfate solution is slightly less than that of the concrete immersed in the sodium sulfate solution.However,in the later stage of corrosion,the sulfate ion content in the concrete immersed in the magnesium sulfate solution is significantly higher than that of the concrete immersed in the sodium sulfate solution.展开更多
High hydrogen absorption and desorption rates are two significant index parameters for the applications of hydrogen storage tanks.The analysis of the hydrogen absorption and desorption behavior using the isothermal ki...High hydrogen absorption and desorption rates are two significant index parameters for the applications of hydrogen storage tanks.The analysis of the hydrogen absorption and desorption behavior using the isothermal kinetic models is an efficient way to investigate the kinetic mechanism.Multitudinous kinetic models have been developed to describe the kinetic process.However,these kinetic models were de-duced based on some assumptions and only appropriate for specific kinetic measurement methods and rate-controlling steps(RCSs),which sometimes lead to confusion during application.The kinetic analysis procedures using these kinetic models,as well as the key kinetic parameters,are unclear for many researchers who are unfamiliar with this field.These problems will prevent the kinetic models and their analysis methods from revealing the kinetic mechanism of hydrogen storage alloys.Thus,this review mainly focuses on the summarization of kinetic models based on different kinetic measurement methods and RCSs for the chemisorption,surface penetration,diffusion of hydrogen,nucleation and growth,and chemical reaction processes.The analysis procedures of kinetic experimental data are expounded,as well as the effects of temperature,hydrogen pressure,and particle radius.The applications of the kinetic models for different hydrogen storage alloys are also introduced.展开更多
In this work,as-cast Mg-Ni-Y alloys were proposed to develop a feasible material for fracturing balls,and their mechanical performance and corrosion behavior were systematically investigated.Long period stacking order...In this work,as-cast Mg-Ni-Y alloys were proposed to develop a feasible material for fracturing balls,and their mechanical performance and corrosion behavior were systematically investigated.Long period stacking order(LPSO)phase was firstly introduced to improve both the mechanical properties and degradation rate of magnesium alloys.With the increase of LPSO phase,the compressive strength was improved significantly,while the elongation of the alloys decreased owing to the relatively brittle nature of LPSO phase.Due to the higher corrosion potential of LPSO phase,the LPSO phase can accelerate the corrosion process by providing more micro-couples.However,the LPSO phase would serve as the corrosion barrier between the corrosion medium and the matrix when the contents of LPSO phase are too high in Mg92.5Ni3Y4.5 and Mg87.5Ni5Y7.5 alloys.As-cast Mg97.5Ni1Y1.5 alloy with satisfactory mechanical properties and rapid degradation rate was successfully developed,exhibiting a high degradation rate of 6675 mm/a(93℃)in 3 wt.%KCl solution and a favorable ultimate compressive strength of 410 MPa.The degradation rate of Mg97.5Ni1Y1.5 alloy is 2-5 times of the current commercial magnesium alloy fracturing materials.展开更多
The mechanical properties and bio-corrosion behaviors of as-extruded Mg-4Zn alloys after Sn addition were investigated,systemati-cally.A small amount of Sn addition to Mg-4Zn alloy slightly improved the mechanical pro...The mechanical properties and bio-corrosion behaviors of as-extruded Mg-4Zn alloys after Sn addition were investigated,systemati-cally.A small amount of Sn addition to Mg-4Zn alloy slightly improved the mechanical properties for solid solution strengthening,and significantly controlled the bio-corrosion rates.Sn participating in the outer layer film formation as SnO/SnO_(2)resisted the bio-corrosion proceeding.Especially,Mg-4Zn-1.5Sn alloy,with a weight loss rate of 0.45 mm/y and hydrogen evolution rate of 0.099 mL/cm^(2)/day,showed cytotoxicity grade of 0 to MC3T3-E1 cells.The perfect alliance of cytocompatibility,suitable mechanical properties and low bio-corrosion rate demonstrates that this Mg-4Zn-1.5Sn alloy is a promising biodegradable magnesium alloy for orthopedic implants.展开更多
The solid–liquid compound casting of Mg-AZ91D and Ti-TC4 alloys was developed by using pure Ni electro-deposited coating.The pouring temperatures of 660℃,690℃,720℃and 750℃were chosen to investigated the effects o...The solid–liquid compound casting of Mg-AZ91D and Ti-TC4 alloys was developed by using pure Ni electro-deposited coating.The pouring temperatures of 660℃,690℃,720℃and 750℃were chosen to investigated the effects of casting temperatures on microstructural evolution,properties,and fracture behaviors of Ni-coated TC4/AZ91D bimetals by the solid–liquid compound casting(SLCC).The scanning electron microscopy(SEM)and the energy dispersive spectroscopy(EDS)results showed that the interfacial zone mainly composed of nickel,Mg_(2)Ni and Mg-Al-Ni in the bimetals cast at 660℃.As the pouring temperature was increased to 750℃,the width of the interface zone,which mainly composed ofδ(Mg),Mg_(2)Ni,Mg-Al-Ni,Mg_(3)TiNi_(2) and Al_(3)Ni,gradually increased.The microhardness tests showed that the micro-hardness of the interface zone was smaller than that of TC4 substrate but larger than that of the cast AZ91D matrix.At the pouring temperature of 720℃,the Ni-coated TC4/AZ91D bimetals had the most typical homogeneous interface,which had granular Mg-Al-Ni ternary phase but no ribbon-like Al3Ni binary phase,and achieved the highest shear strength of 97.35MPa.Meanwhile,further fracture behavior analysis showed that most fracture failure of Ni-coated TC4/AZ91D bimetals occurred at the Mg_(2)Ni+δ(Mg)eutectic structure and Al_(3)Ni hard intermetallic.展开更多
In this study,the optimization of mechanical and damping capacities of Mg-0.6 wt.%Zr alloys by controlling the recrystallized(DRXed)grain size under varying extrusion processing parameters including extrusion temperat...In this study,the optimization of mechanical and damping capacities of Mg-0.6 wt.%Zr alloys by controlling the recrystallized(DRXed)grain size under varying extrusion processing parameters including extrusion temperature T and strain rate was investigated.The relationship between the DRXed grain size and damping properties of the studied alloy was also discussed.The DRXed grain size of the as-extruded Mg-Zr alloys decreased as the extrusion temperature T decreased and the strain rateεincreased.As the DRXed grain size decreased,the strength and elongation of the as-extruded alloys exhibited improved performance through the grain refinement mechanism,while the damping properties deteriorated.The extrusion temperature of the Mg-Zr alloy had relatively greater effects on the mechanical and damping properties than the strain rate.The results of the present work indicate that alloys with appropriate mechanical and damping properties may be obtained from controlling the DRXed grain size by careful tailoring of the extrusion process parameters.展开更多
The low-density magnesium(Mg)alloys are attractive for the application in aerospace,transportation and other weight-saving-required fields.The mechanical properties and corrosion properties of Mg alloys are the key-pr...The low-density magnesium(Mg)alloys are attractive for the application in aerospace,transportation and other weight-saving-required fields.The mechanical properties and corrosion properties of Mg alloys are the key-property issues for the wide application.It is surprising to find that the solid solution of alloying elements in theα-Mg phase can have multi-effects on the properties of Mg alloys,e.g.,solid solution strengthening,solid solution corrosion-resistance-enhancing,etc.Additionally,the alloy design theory of"solid solution strengthening and ductilizing"proposed by Pan and co-workers has attracted extensive attentions.It is promising that by selected proper multi-alloying-elements(with optimal ratio)solid solutioned in theα-Mg phase,the comprehensive properties of Mg alloys can be synergistically improved.In this work,the solid solution behavior of Mg alloys and the followed solid solution property-enhancing effects were reviewed.The mechanisms proposed recently by researchers for these solid solution property-enhancing behaviors were presented,and the related calculations and predictions were also described.It is shown the demonstrations of the fundamentals for the solid solution property-enhancing of Mg alloys,especially from the atomic inter-reaction aspects,still require elaborated characterization work and calculation work.Additionally,it could be expected that the multi-solute in Mg alloys can bring many possibilities,or,in another saying,"cocktail effects".With understanding the multi-solute interaction behavior and the corresponded solid solution property-enhancing effects,the good balanced high-performance Mg alloys can be developed.展开更多
This study analyzes the effect of substitution of Ni for Zn on microstructure and mechanical properties of Mg-Gd-Y-Zn-Mn alloy.Our results show that the volume fraction of Mg5(Gd,Y)and(Mg,Zn)3RE phase decreased and LP...This study analyzes the effect of substitution of Ni for Zn on microstructure and mechanical properties of Mg-Gd-Y-Zn-Mn alloy.Our results show that the volume fraction of Mg5(Gd,Y)and(Mg,Zn)3RE phase decreased and LPSO phase increased with more substitution of Ni.After homogenization,onlyα-Mg and LPSO phase existed.In Mg-Gd-Y-Zn-Mn alloys,the LPSO phases mainly consisted of the 14H type.While in Mg-Gd-Y-Ni-Mn alloy,the LPSO phases consisted of the 18R type.In addition,compared with Mg-Gd-Y-Zn-Mn alloy,the mechanical properties of as-extruded Ni-substitution alloys were improved due to the better refinement of the size of grains and LPSO phases.The tensile strength in as-extruded Mg-Gd-Y-Ni-Mn alloy could reach up to 400 MPa with 18%of the elongation to failure.展开更多
To meet the growing demand for antibacterial implants for bone-implant-associated infection therapy and avoid the adverse effects of secondary surgery,a degradable platform with pH responsiveness and ion-associated an...To meet the growing demand for antibacterial implants for bone-implant-associated infection therapy and avoid the adverse effects of secondary surgery,a degradable platform with pH responsiveness and ion-associated antibacterial properties was constructed.A small amount of Sn added to Mg-1Zn alloy reduces the biocorrosion rate,which can be attributed to Sn participation in outer-layer film formation,significantly reducing the biocorrosion rate and hydrogen evolution rate after implantation in vivo.These Mg alloys,which are susceptible to degradation in the acidic bacterial microenvironment,degrade by releasing Mg,Zn and Sn,producing favorably alkaline and antibacterial conditions.Samples with the composition of Mg-1Zn-0.5Sn were found to be beneficial for promoting initial cell adhesion and proliferation,resulting in improved biocompatibility and biosafety.The biocompatibility of this alloy was confirmed by the healthy behavior of animals and the absence of acute or chronic toxicity in the liver,spleen,and kidneys.Our results demonstrate that Mg-1Zn-0.5Sn is safe for biological systems,enabling its efficacious use in biomedical applications.展开更多
Objective:The head-up tilt test(HUTT)is widely used but is time-consuming and not cost-effective to evaluate patients with vasovagal syncope(VVS).The present study aims to verify the hypothesis that ambulatory blood p...Objective:The head-up tilt test(HUTT)is widely used but is time-consuming and not cost-effective to evaluate patients with vasovagal syncope(VVS).The present study aims to verify the hypothesis that ambulatory blood pressure(BP)monitoring(ABPM)and the simplistic tilt test may be potential alternatives to the HUTT.Methods:The study consecutively enrolled 360 patients who underwent the HUTT to evaluate VVS.BP),heart rate(HR),and BP/HR ratios derived from ABPM and the simplistic tilt test were evaluated to predict the presence,pattern,and stage of syncope during the HUTT.Results:Mixed response was the commonest pattern,and syncope occurred frequently with infusion of isoproterenol at a rate of 3μg/min.During the simplistic tilt test,the cardioinhibitory group had higher tilted BP/HR ratios than the vasodepressor group,while the vasodepressor group had a faster tilted HR and a larger HR difference than the cardioinhibitory group.The higher the BP/HR ratio in the tilted position,the higher the isoproterenol dosage needed to induce a positive response.During ABPM,BP/HR ratios were signifi cantly higher in the cardioinhibitory group than in the vasodepressor group.The higher the ABPM-derived BP,the higher the dosage of isoproterenol needed to induce syncope.There were signifi cant correlations in BP/HR ratios between ABPM and the supine position in the vasodepressor group,while signifi cant correlation was found only for the diastolic BP/HR ratio between ABPM and the tilted position in the cardioinhibitory group.The mixed pattern shared correlative features of the other two patterns.Conclusion:ABPM and the simplistic tilt test might be used as promising alternatives to the HUTT in VVS evaluation in clinical settings.展开更多
基金funded by the National Natural Science Foundation of China(Nos.51801189)The Central Guidance on Local Science and Technology Development Fund of Shanxi Province(Nos.YDZJTSX2021A027)+2 种基金The National Natural Science Foundation of China(Nos.51801189)The Science and Technology Major Project of Shanxi Province(No.20191102008,20191102007)The North University of China Youth Academic Leader Project(No.11045505).
文摘This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the focus.The morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered network.After heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R structure.As Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloy.Both Zn and the heat treatment had a significant effect on damping.Obvious dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys.After heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).66.The annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom content.These factors also affected the dynamic modulus of the alloy.The results of this study will help in further development of high-damping magnesium alloys.
基金supported by the National Natural Science Foundation of China(52222407).
文摘Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategies have been devised to enhance the Mg^(2+)migration kinetics and structural stability of cathodes,they fail to improve electronic conductivity,rendering the cathodes incompatible with magnesium-metal anodes.Herein,we propose a dual-defect engineering strategy,namely,the incorporation of Mg^(2+)pre-intercalation defect(P-Mgd)and oxygen defect(Od),to simultaneously improve the Mg^(2+)migration kinetics,structural stability,and electronic conductivity of the cathodes of RMMBs.Using lamellar V_(2)O_(5)·nH_(2)O as a demo cathode material,we prepare a cathode comprising Mg_(0.07)V_(2)O_(5)·1.4H_(2)O nanobelts composited with reduced graphene oxide(MVOH/rGO)with P-Mgd and Od.The Od enlarges interlayer spacing,accelerates Mg^(2+)migration kinetics,and prevents structural collapse,while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity.Consequently,the MVOH/rGO cathode exhibits a high capacity of 197 mAh g^(−1),and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g^(−1),capable of powering a light-emitting diode.The proposed dual-defect engineering strategy provides new insights into developing high-durability,high-capacity cathodes,advancing the practical application of RMMBs,and other new secondary batteries.
基金supported by the National Key R&D Program of China(No.2023YFB3809500)the National Natural Science Foundation of China(No.U23A20555,52202211)+3 种基金the Ninth Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the Chongqing Technology Innovation and Application Development Project(No.CSTB2022TIAD-KPX0028)the Fundamental Research Funds for the Central Universities(2023CDJXY-018)the Venture&Innovation Support Program for Chongqing Overseas Returnees(cx2022119,cx2023087).
文摘Rechargeable magnesium batteries(RMBs),as a low-cost,high-safety and high-energy storage technology,have attracted tremendous attention in large-scale energy storage applications.However,the key anode/electrolyte interfacial issues,including surface passivation,uneven Mg plating/stripping,and pulverization after cycling still result in a large overpotential,short cycling life,poor power density,and possible safety hazards of cells,severely impeding the commercial development of RMBs.In this review,a concise overview of recently advanced strategies to address these anode/electroyte interfacial issues is systematically classified and summarized.The design of magnesiophilic substrates,construction of artificial SEI layers,and modification of electrolyte are important and effective strategies to improve the uniformity/kinetics of Mg plating/stripping and achieve the stable anode/electrolyte interface.The key opportunities and challenges in this field are advisedly put forward,and the insights into future directions for stabilizing Mg metal anodes and the anode/electrolyte interface are highlighted.This review provides important references fordeveloping the high-performance and high-safety RMBs.
基金supported by the National Key R&D Program of China(No.2023YFB3809500)the National Natural Science Foundation of China(No.U23A20555,52202211)+1 种基金the Ninth Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the Chongqing Technology Innovation and Application Development Project(No.CSTB2022TIAD-KPX0028).
文摘Rechargeable Mg batteries(RMBs)have become one of the best subsitutes for lithium-ion batteries due to the high volumetric capacity,abundant resources,and uniform plating behavior of Mg metal anode.However,the safety hazard induced by the formation of high-modulue Mg dendrites under a high current density(10 mA cm^(-1))was still revealed in recent years.It has forced researchers to re-examine the safety of RMBs.In this review,the intrinsic safety factors of key components in RMBs,such as uneven plating,pitting and flammability of Mg anode,heat release and crystalline water decomposition of cathode,strong corrosion,low oxidition stability and flammability of electrolytes,and soforth,are systematacially summarized.Their origins,formation mechanisms,and possible safety hazards are deeply discussed.To develop high-performance Mg anode,current strategies including designing artificial SEI,three-dimensional substrates,and Mg alloys are summarized.For practical electrolytes,the configurations of boron-centered anions and simple Mg salts and the functionalized solvent with high boiling point and low flammability are suggested to comprehensively design.In addition,the future study should more focus on the investigation on the thermal runaway and decomposition of cathode materials and separa-tors.This review aims to provide fundamental insights into the relationship between electrochemistry and safety,further promoting the sustainable development of RMBs.
基金the financial support from the National Key Research and Development Program of China(No.2021YFB3701100)the Natural Science Foundation Commission of China(Grant Nos.U20A20234,51874062)+3 种基金the Chongqing Foundation and Advanced Research Project(Grant No.cstc2019jcyj-zdxm X0010)Fundamental Research Funds for the Central Universities(No.2022CDJKYJH004)the Science and Technology Major Project of Shanxi Province(No.20191102008)University Innovation Research Group of Chongqing(CXQT20023)。
文摘In this study,Mg-13.2Gd-4.3Ni alloys containing continuous bulk-shaped long-period stacking ordered(LPSO),lamellar LPSO,and a small amount of eutectic phase were prepared,and the evolution of microstructure at different extrusion temperatures and its influence on mechanical and degradation properties as well as corrosion mechanism were investigated.Preheating before extrusion can effectively promote the precipitation of lamellar LPSO in matrix.EX400 with higher volume fraction of non-DRXed grains exhibited higher strength,which was mainly due to strong texture,high dislocation density,and high volume fraction of lamellar LPSO.The EX420 with higher volume fraction of DRXed grains showed higher degradation rate,which was mainly due to the higher density of grain boundary.The EX400 exhibited excellent comprehensive properties with tensile yield strength(TYS)of 334 MPa,ultimate tensile strength(UTS)of 484 MPa and elongation(EL)of 7.4%,ultimate compressive strength(UCS)of 638 MPa and compressive yield strength(CYS)of 443 MPa,degradation rate of 86.1 mg/cm^(2)/h at 93℃in 3 wt.%KCl solution.
基金supported by The National Key Research and Development Program of China(2023YFB3809100)the National Natural Science Foundation of China(U23A200722)the Fundamental Research Funds for the Central Universities(2023CDJXY-016).
文摘While TiFe alloy has recently attracted attention as the efficient catalyst to enhance de/hydrogenation rates of Mg/MgH_(2),the difficulty of its activation characteristics has hindered further improvement of reaction kinetics.Herein,we report that the TiFe_(0.92)Mn_(0.04)Co_(0.04) catalyst can overcome the abovementioned challenges.The synthesized MgH_(2)-30 wt% TiFe_(0.92)Mn_(0.04)Co_(0.04) can release 4.5 wt%of hydrogen in 16 min at 250℃,three times as fast as MgH_(2).The activation energy of dehydrogenation was as low as 84.6 kJ mol^(-1),which is 46.8%reduced from pure MgH_(2).No clear degradation of reaction rates and hydrogen storage capacity was observed for at least 30 cycles.Structural studies reveal that TiFe_(0.92)Mn_(0.04)Co_(0.04) partially decomposes to in-situ generatedα-Fe particles dispersed on TiFe_(0.92)Mn_(0.04)Co_(0.04).The presence ofα-Fe reduces the formation of an oxide layer on TiFe_(0.92)Mn_(0.04)Co_(0.04),enabling the activation processes.At the same time,the hydrogen incorporation capabilities of TiFe_(0.92)Mn_(0.04)Co_(0.04) can provide more hydrogen diffusion paths,which promote hydrogen dissociation and diffusion.These discoveries demonstrate the advanced nature and importance of combining the in-situ generatedα-Fe with TiFe_(0.92)Mn_(0.04)Co_(0.04).It provides a new strategy for designing highly efficient and stable catalysts for Mg-based hydrogen storage materials.
基金financial support from the National Key Research and Development Program of China (No.2021YFB3502200)the National Natural Science Foundation of China (Grants Nos.52271202,51971040,52171101)+2 种基金the Shanghai Rising-Star Program (No.21QA1403200)supported by a start-up fund from Chongqing University (02110011044171)Liuchuang Program of Chongqing Municipality (cx2022038)。
文摘Magnesium-based energy materials, which combine promising energy-related functional properties with low cost, environmental compatibility and high availability, have been regarded as fascinating candidates for sustainable energy conversion and storage. In this review,we provide a timely summary on the recent progress in three types of important Mg-based energy materials, based on the fundamental strategies of composition and structure engineering. With regard to Mg-based materials for batteries, we systematically review and analyze different material systems, structure regulation strategies as well as the relevant performance in Mg-ion batteries(MIBs) and Mg-air batteries(MABs), covering cathodes, electrolytes, anodes for MIBs, and anodes for MABs;as to Mg-based hydrogen storage materials, we discuss how catalyst adding, composite, alloying and nanostructuring improve the kinetic and thermodynamic properties of de/hydrogenation reactions, and in particular, the impacts of composition and structure modification on hydrogen absorption/dissociation processes and free energy modification mechanism are focused;regarding Mg-based thermoelectric materials, the relations between composition/structure and electrical/thermal transport properties of Mg_(3)X_(2)(X = Sb, Bi), Mg_(2)X(X = Si, Ge, Sn) and Mg Ag Sb-based materials, together with the representative research progress of each material system, are summarized and discussed. Finally, by pointing out remaining challenges and providing possible solutions, this review aims to shed light on the directions and perspectives for practical applications of magnesium-based energy materials in the future.
基金financially supported by the Fundamental Research Funds for the Central Universities(NO.2021CDJXDJH003)Guangdong National Technology Co.,Ltd.
文摘Owing to the features(high safety,inexpensive and environmental friendliness)of aqueous rechargeable Mg-ion batteries(ARMIBs),they have drawn extensive attention in the future energy storage systems.However,the poor Mg^(2+)migration kinetics during the Mg^(2+)intercalation/extraction still hinders the progress of developing suitable cathode materials.Herein,a layered buserite Mg-Mn oxide(MMO)material with large interlayer space(~9.70A)and low-crystalline structure is studied as a high-performance cathode in ARMIBs.Compared with the counterpart,the Mg^(2+)migration kinetics of the MMO cathode can be enhanced by its unique structure(bigger interlayer spacing and low-crystalline structure).The layered buserite MMO as a high-performance ARMIBs cathode exhibits high Mg storage capacity(50 mAg^(-1):169.3 mAh g^(-1)),excellent rate capability(1000 mAg^(-1):98.3 mAh g^(-1)),and fast Mg^(2+)migration(an average diffusion coefficient:~4.21×10-^(10)cm^(2)s^(-1))in 0.5 M MgCl_(2)aqueous electrolyte.Moreover,the MMO-1//AC full battery achieved a high discharge capacity(100 mAg^(-1):111 mAh g^(-1)),and an ignored fading over 5000 cycles(1000 mAg^(-1)).Therefore,layered Mg-Mn oxide with large interlayer space may break a new path to develop the promising ARMIBs.
基金This work was supported by the National Natural Science Foundation of China[Grant No.32000832]the Shandong Province Natural Science Foundation[Grant No.ZR2020QC096].
文摘Presenilin(Psn)protein is associated with organismal aging.Mutations in the Psn gene may lead to Alzheimer’s disease(AD),dilated cardiomyopathy(DCM),and many age-dependent degenerative diseases.These diseases seriously affect the quality of life and longevity of the population and place a huge burden on health care and economic systems around the world.Humans have two types of Psn,presenilin-1(PSEN1)and presenilin-2(PSEN2).Mutations in the genes encoding PSEN1,PSEN2,and amyloid precursor protein(APP)have been identified as the major genetic causes of AD.Psn is a complex gene strongly influenced by genetic and environmental factors.The effects of exercise,training,and a high-fat diet on the Psn gene expressed in the heart and its related pathways are not fully understood.Fortunately,relevant aspects of the mutational effects on Psn can be studied experimentally in easily handled animal models,including Drosophila,mice,and other animals,all of which share orthologous genes of Psn with humans.Many previous studies have linked aging,exercise training,and a high-fat diet to the Psn gene.This review discusses the interrelationship between aging,exercise training,and a high-fat diet on the Psn gene and its associated disease,AD.The aim is to understand the adverse effects of Psn gene mutations on the body and the diseases caused by AD,find ways to alleviate the adverse effects and provide new directions for the improvement of treatment strategies for diseases caused by Psn gene mutations.
基金gratefully acknowledge Chongqing Talent Plan: Leading Talents in Innovation and Entrepreneurship (CQYC201903051)University Innovation Research Group of Chongqing (CXQT20023)Natural Science Foundation of Chongqing (cstc2021ycjh-bgzxm0184)。
文摘It is recently suggested that air-formed film plays an important role in controlling corrosion resistance of Mg-Li alloys. However, the structure of the air-formed film and its effect on corrosion resistance of Mg-Li alloys has not been fully understood. Firstly, the air-formed films formed on α and β phases in a dual-phase LZ91 Mg-Li alloy after exposure to laboratory air for up to 48 h have been examined by SEM under the assistance of ultramicrotomy. Then, the effect of the air-formed film on surface potential and, consequently, corrosion/oxidation behavior of the alloy has been investigated. Finally, in order to exclude the influence from α phase, the structure of the air-formed film on β phase and its effect on corrosion/oxidation behavior of Mg-Li alloys have been studied based on a single-phase LA141 Mg-Li alloy. The results show that the air-formed film is thin and negligible on α phase but thick on β phase after prolonged exposure to laboratory air. The thick air-formed film on β phase has a multilayer structure with an inner layer consisting of Mg O/Mg(OH)_(2) and outer layer consisting of Li_(2)CO_(3), which greatly elevates the surface potential of β phase in air. Both LZ91 and LA141 Mg-Li alloys firstly undergo uniform corrosion and then filiform corrosion when immersed in Na Cl solution and the pre-existed air-formed film on β-Li phase can retard the occurrence of filiform corrosion in the alloys.
基金supported by“the National Natural Science Foundation of China(Grant No.52008146)”“the Research Fund of Henan Key Laboratory of Materials on Deep-Earth Engineering(Grant No.MDE2020-01,Henan Polytechnic University)”+1 种基金“the Fundamental Research Funds for the Central Universities of China(Grant Nos.JZ2021HGTB0089,JZ2020HGQA0205)”“State Key Laboratory of High Performance Civil Engineering Materials(2021CEM003)”.
文摘In this paper,the effects of different mineral admixtures and sulfate solution types on the appearance,mass change rate,relative dynamic elastic modulus,and corrosion resistance coefficient of concrete were systematically studied.X-ray Diffraction(XRD),Mercury Intrusion Porosimetry(MIP),Scanning Electron Microscopy(SEM),and X-ray Computed Tomography(X-CT)were used to explore and analyze the changes in the microstructure and the corrosion products of concrete in the sulfate solution.The results show that the existence of magnesium ions accelerates concrete deterioration.There is a critical dosage of fly ash for magnesium sulfate resistance of concrete.The magnesium sulfate resistance of concrete is improved when the fly ash content is less than 20%.Slag can significantly improve the corrosion resistance of concrete to magnesium sulfate.The diffusion of sulfate ions into concrete is a gradual process.In the early stages of corrosion,sulfate ion content in the concrete immersed in the magnesium sulfate solution is slightly less than that of the concrete immersed in the sodium sulfate solution.However,in the later stage of corrosion,the sulfate ion content in the concrete immersed in the magnesium sulfate solution is significantly higher than that of the concrete immersed in the sodium sulfate solution.
基金This work was financially supported by the Chongqing Special Key Project of Technology Innovation and Applica-tion Development,China(No.cstc2019jscx-dxwtB0029)the National Natural Science Foundation of China(Nos.51871143 and U2102212)+1 种基金the Science and Technology Committee of Shanghai,China(No.19010500400)the Shanghai Rising-Star Program(No.21QA1403200).
文摘High hydrogen absorption and desorption rates are two significant index parameters for the applications of hydrogen storage tanks.The analysis of the hydrogen absorption and desorption behavior using the isothermal kinetic models is an efficient way to investigate the kinetic mechanism.Multitudinous kinetic models have been developed to describe the kinetic process.However,these kinetic models were de-duced based on some assumptions and only appropriate for specific kinetic measurement methods and rate-controlling steps(RCSs),which sometimes lead to confusion during application.The kinetic analysis procedures using these kinetic models,as well as the key kinetic parameters,are unclear for many researchers who are unfamiliar with this field.These problems will prevent the kinetic models and their analysis methods from revealing the kinetic mechanism of hydrogen storage alloys.Thus,this review mainly focuses on the summarization of kinetic models based on different kinetic measurement methods and RCSs for the chemisorption,surface penetration,diffusion of hydrogen,nucleation and growth,and chemical reaction processes.The analysis procedures of kinetic experimental data are expounded,as well as the effects of temperature,hydrogen pressure,and particle radius.The applications of the kinetic models for different hydrogen storage alloys are also introduced.
基金This work is financially supported by the National Key Research and Development Program of China(Grant No.2016YFB0301100)the Chongqing Foundation and Advanced Research Project(Grant No.cstc2019jcyj-zdxmX0010)+1 种基金the Natural Science Foundation Commission of China(Grant No.51571044 and 51874062)Fundamental Research Funds for the Central Universities(Grant No.2018CDGFCL0005 and 2019CDXYCL0031).
文摘In this work,as-cast Mg-Ni-Y alloys were proposed to develop a feasible material for fracturing balls,and their mechanical performance and corrosion behavior were systematically investigated.Long period stacking order(LPSO)phase was firstly introduced to improve both the mechanical properties and degradation rate of magnesium alloys.With the increase of LPSO phase,the compressive strength was improved significantly,while the elongation of the alloys decreased owing to the relatively brittle nature of LPSO phase.Due to the higher corrosion potential of LPSO phase,the LPSO phase can accelerate the corrosion process by providing more micro-couples.However,the LPSO phase would serve as the corrosion barrier between the corrosion medium and the matrix when the contents of LPSO phase are too high in Mg92.5Ni3Y4.5 and Mg87.5Ni5Y7.5 alloys.As-cast Mg97.5Ni1Y1.5 alloy with satisfactory mechanical properties and rapid degradation rate was successfully developed,exhibiting a high degradation rate of 6675 mm/a(93℃)in 3 wt.%KCl solution and a favorable ultimate compressive strength of 410 MPa.The degradation rate of Mg97.5Ni1Y1.5 alloy is 2-5 times of the current commercial magnesium alloy fracturing materials.
基金The authors are grateful for the financial support from the National Key Research and Development Program of China(No.2016YFB0301100)the National Natural Science Foundation of China(Grant Nos.51571044,51671162 and 51874062)the Fundamental Research Funds for the Cen-tral Universities(No.2018CDGFCL0005).
文摘The mechanical properties and bio-corrosion behaviors of as-extruded Mg-4Zn alloys after Sn addition were investigated,systemati-cally.A small amount of Sn addition to Mg-4Zn alloy slightly improved the mechanical properties for solid solution strengthening,and significantly controlled the bio-corrosion rates.Sn participating in the outer layer film formation as SnO/SnO_(2)resisted the bio-corrosion proceeding.Especially,Mg-4Zn-1.5Sn alloy,with a weight loss rate of 0.45 mm/y and hydrogen evolution rate of 0.099 mL/cm^(2)/day,showed cytotoxicity grade of 0 to MC3T3-E1 cells.The perfect alliance of cytocompatibility,suitable mechanical properties and low bio-corrosion rate demonstrates that this Mg-4Zn-1.5Sn alloy is a promising biodegradable magnesium alloy for orthopedic implants.
基金The authors would like to acknowledge the financial supports from the National Natural Science Foundation of China(No.51875062).
文摘The solid–liquid compound casting of Mg-AZ91D and Ti-TC4 alloys was developed by using pure Ni electro-deposited coating.The pouring temperatures of 660℃,690℃,720℃and 750℃were chosen to investigated the effects of casting temperatures on microstructural evolution,properties,and fracture behaviors of Ni-coated TC4/AZ91D bimetals by the solid–liquid compound casting(SLCC).The scanning electron microscopy(SEM)and the energy dispersive spectroscopy(EDS)results showed that the interfacial zone mainly composed of nickel,Mg_(2)Ni and Mg-Al-Ni in the bimetals cast at 660℃.As the pouring temperature was increased to 750℃,the width of the interface zone,which mainly composed ofδ(Mg),Mg_(2)Ni,Mg-Al-Ni,Mg_(3)TiNi_(2) and Al_(3)Ni,gradually increased.The microhardness tests showed that the micro-hardness of the interface zone was smaller than that of TC4 substrate but larger than that of the cast AZ91D matrix.At the pouring temperature of 720℃,the Ni-coated TC4/AZ91D bimetals had the most typical homogeneous interface,which had granular Mg-Al-Ni ternary phase but no ribbon-like Al3Ni binary phase,and achieved the highest shear strength of 97.35MPa.Meanwhile,further fracture behavior analysis showed that most fracture failure of Ni-coated TC4/AZ91D bimetals occurred at the Mg_(2)Ni+δ(Mg)eutectic structure and Al_(3)Ni hard intermetallic.
基金The authors are grateful for the financial support from the foundation support of the Key Laboratory of Science and Technology on High Energy Laser,CAEP,the National Natural Science Foundation Commission of China(Grant No.51271206)the National Basic Research Program of China(Grant No.2013CB632201)the Program for New Century Excellent Talents in University(Grant No.NCET-11-0554).
文摘In this study,the optimization of mechanical and damping capacities of Mg-0.6 wt.%Zr alloys by controlling the recrystallized(DRXed)grain size under varying extrusion processing parameters including extrusion temperature T and strain rate was investigated.The relationship between the DRXed grain size and damping properties of the studied alloy was also discussed.The DRXed grain size of the as-extruded Mg-Zr alloys decreased as the extrusion temperature T decreased and the strain rateεincreased.As the DRXed grain size decreased,the strength and elongation of the as-extruded alloys exhibited improved performance through the grain refinement mechanism,while the damping properties deteriorated.The extrusion temperature of the Mg-Zr alloy had relatively greater effects on the mechanical and damping properties than the strain rate.The results of the present work indicate that alloys with appropriate mechanical and damping properties may be obtained from controlling the DRXed grain size by careful tailoring of the extrusion process parameters.
基金financially National Natural Science Foundation of China(52171100,51971044,U20A20234 and U1910213)the National Key R&D Program of China(2021YFB3701100)the Natural Science Foundation of Chongqing(cstc2019yszx-jcyj X0004)。
文摘The low-density magnesium(Mg)alloys are attractive for the application in aerospace,transportation and other weight-saving-required fields.The mechanical properties and corrosion properties of Mg alloys are the key-property issues for the wide application.It is surprising to find that the solid solution of alloying elements in theα-Mg phase can have multi-effects on the properties of Mg alloys,e.g.,solid solution strengthening,solid solution corrosion-resistance-enhancing,etc.Additionally,the alloy design theory of"solid solution strengthening and ductilizing"proposed by Pan and co-workers has attracted extensive attentions.It is promising that by selected proper multi-alloying-elements(with optimal ratio)solid solutioned in theα-Mg phase,the comprehensive properties of Mg alloys can be synergistically improved.In this work,the solid solution behavior of Mg alloys and the followed solid solution property-enhancing effects were reviewed.The mechanisms proposed recently by researchers for these solid solution property-enhancing behaviors were presented,and the related calculations and predictions were also described.It is shown the demonstrations of the fundamentals for the solid solution property-enhancing of Mg alloys,especially from the atomic inter-reaction aspects,still require elaborated characterization work and calculation work.Additionally,it could be expected that the multi-solute in Mg alloys can bring many possibilities,or,in another saying,"cocktail effects".With understanding the multi-solute interaction behavior and the corresponded solid solution property-enhancing effects,the good balanced high-performance Mg alloys can be developed.
基金supported by the National Key Research and Development Program of China(No.2016YFB0301100)the Natural Science Foundation Commission of China(Grant No.51571044)+1 种基金Chongqing foundation and advanced research project(Grant No.cstc2015jcyjBX0081)the National Basic Research Program of China(Grant No.2013 CB632201)。
文摘This study analyzes the effect of substitution of Ni for Zn on microstructure and mechanical properties of Mg-Gd-Y-Zn-Mn alloy.Our results show that the volume fraction of Mg5(Gd,Y)and(Mg,Zn)3RE phase decreased and LPSO phase increased with more substitution of Ni.After homogenization,onlyα-Mg and LPSO phase existed.In Mg-Gd-Y-Zn-Mn alloys,the LPSO phases mainly consisted of the 14H type.While in Mg-Gd-Y-Ni-Mn alloy,the LPSO phases consisted of the 18R type.In addition,compared with Mg-Gd-Y-Zn-Mn alloy,the mechanical properties of as-extruded Ni-substitution alloys were improved due to the better refinement of the size of grains and LPSO phases.The tensile strength in as-extruded Mg-Gd-Y-Ni-Mn alloy could reach up to 400 MPa with 18%of the elongation to failure.
文摘To meet the growing demand for antibacterial implants for bone-implant-associated infection therapy and avoid the adverse effects of secondary surgery,a degradable platform with pH responsiveness and ion-associated antibacterial properties was constructed.A small amount of Sn added to Mg-1Zn alloy reduces the biocorrosion rate,which can be attributed to Sn participation in outer-layer film formation,significantly reducing the biocorrosion rate and hydrogen evolution rate after implantation in vivo.These Mg alloys,which are susceptible to degradation in the acidic bacterial microenvironment,degrade by releasing Mg,Zn and Sn,producing favorably alkaline and antibacterial conditions.Samples with the composition of Mg-1Zn-0.5Sn were found to be beneficial for promoting initial cell adhesion and proliferation,resulting in improved biocompatibility and biosafety.The biocompatibility of this alloy was confirmed by the healthy behavior of animals and the absence of acute or chronic toxicity in the liver,spleen,and kidneys.Our results demonstrate that Mg-1Zn-0.5Sn is safe for biological systems,enabling its efficacious use in biomedical applications.
基金the Guangdong Natural Science Foundation Project(2018A030313531)the Yat-Sen Scholarship for Young Scientists.
文摘Objective:The head-up tilt test(HUTT)is widely used but is time-consuming and not cost-effective to evaluate patients with vasovagal syncope(VVS).The present study aims to verify the hypothesis that ambulatory blood pressure(BP)monitoring(ABPM)and the simplistic tilt test may be potential alternatives to the HUTT.Methods:The study consecutively enrolled 360 patients who underwent the HUTT to evaluate VVS.BP),heart rate(HR),and BP/HR ratios derived from ABPM and the simplistic tilt test were evaluated to predict the presence,pattern,and stage of syncope during the HUTT.Results:Mixed response was the commonest pattern,and syncope occurred frequently with infusion of isoproterenol at a rate of 3μg/min.During the simplistic tilt test,the cardioinhibitory group had higher tilted BP/HR ratios than the vasodepressor group,while the vasodepressor group had a faster tilted HR and a larger HR difference than the cardioinhibitory group.The higher the BP/HR ratio in the tilted position,the higher the isoproterenol dosage needed to induce a positive response.During ABPM,BP/HR ratios were signifi cantly higher in the cardioinhibitory group than in the vasodepressor group.The higher the ABPM-derived BP,the higher the dosage of isoproterenol needed to induce syncope.There were signifi cant correlations in BP/HR ratios between ABPM and the supine position in the vasodepressor group,while signifi cant correlation was found only for the diastolic BP/HR ratio between ABPM and the tilted position in the cardioinhibitory group.The mixed pattern shared correlative features of the other two patterns.Conclusion:ABPM and the simplistic tilt test might be used as promising alternatives to the HUTT in VVS evaluation in clinical settings.
