This paper presents a novel blockchain-embedded cybersecurity framework for industrial solar power systems,integrating immutable machine learning(ML)with distributed ledger technology.Our contribution focused on three...This paper presents a novel blockchain-embedded cybersecurity framework for industrial solar power systems,integrating immutable machine learning(ML)with distributed ledger technology.Our contribution focused on three factors,Quantum-resistant feature engineering using theUNSW-NB15 dataset adapted for solar infrastructure anomalies.An enhanced Light Gradient Boosting Machine(LightGBM)classifier with blockchain-validated decision thresholds,and A cryptographic proof-of-threat(PoT)consensus mechanism for cyber attack verification.The proposed Immutable LightGBM model with majority voting and cryptographic feature encoding achieves 96.9% detection accuracy with 0.97 weighted average of precision,recall and F1-score,outperforming conventional intrusion detection systems(IDSs)by 12.7% in false positive reduction.The blockchain layer demonstrates a 2.4-s average block confirmation time with 256-bit SHA-3 hashing,enabling real-time threat logging in photovoltaic networks.Experimental results improve in attack traceability compared to centralized security systems,establishing new benchmarks for trustworthy anomaly detection in smart grid infrastructures.This study also compared traditional and hybrid ML based blockchian driven IDSs and attained better classification results.The proposed framework not only delivers a resilient,adaptable threat mitigation system(TMS)for Industry 4.0 solar powered infrastructure but also attains high explainability,scalability with tamper-proof logs,and remarkably exceptional ability of endurance to cyber attacks.展开更多
A novel continuous plastic process employed on AZ31 Mg alloy called closed forging extrusion(CFE)was presented.The optical microscopy,scanning electron microscopy,electron back-scatter diffraction and tensile and comp...A novel continuous plastic process employed on AZ31 Mg alloy called closed forging extrusion(CFE)was presented.The optical microscopy,scanning electron microscopy,electron back-scatter diffraction and tensile and compressive tests were employed to investigate the microstructure evolution and strengthening mechanism.The results indicated that the CFE-process can promote dynamic recrystallization(DRX),eliminate the coarsen unDRXed grain regions,refine the grains effectively,and improve the strength,plasticity and anisotropy of the alloy.The grain refinement was mainly attributed to the stress,which facilitated the nucleation of recrystallization and refined the microstructure via the CFE.The fully DRXed ultrafine grained structure improved the strength and plasticity simultaneously.After 60 s closed forging and continuous extrusion,the alloy exhibits relatively high TYS,UTS,CYS,elongation and yield asymmetry of 305 MPa,337 MPa,295 MPa,27%and 0.97,respectively.展开更多
Mg−9Al−1Zn(AZ91)magnesium matrix composites reinforced by Ti−6Al−4V(TC4)particles were successfully prepared via powder metallurgical method.The yield strength(YS),ultimate tensile strength(UTS),and elongation(EL)show...Mg−9Al−1Zn(AZ91)magnesium matrix composites reinforced by Ti−6Al−4V(TC4)particles were successfully prepared via powder metallurgical method.The yield strength(YS),ultimate tensile strength(UTS),and elongation(EL)showed a mountain-like tendency with the increase of the TC4 content.The mechanical properties of AZ91 magnesium matrix composites reached the optimal point with TC4 content of 10 wt.%,realizing YS,UTS,and EL of 335 MPa,370 MPa,and 6.4%,respectively.The improvement of mechanical properties can be attributed to the effective load transfer from the magnesium matrix to the TC4 particles,dislocations associated with the difference in the coefficient of thermal expansion,good interfacial bonding between the Mg matrix and TC4 particles,and grain refinement strengthening.展开更多
Nano-scaled ZrNbAlN films with different negative bias voltages（Vb） were deposited on bronze substrate and Si（100） wafers by a reactive unbalanced magnetron sputtering technique. Composition and structure properti...Nano-scaled ZrNbAlN films with different negative bias voltages（Vb） were deposited on bronze substrate and Si（100） wafers by a reactive unbalanced magnetron sputtering technique. Composition and structure properties were characterized by X-ray photoelectron spectroscopy and X-ray diffraction. It is found that mole concentrations of Zr and Nb are affected by Vb, which leads to the increase of binding energy of N 1s and Al 2p and decrease of binding energy of Zr 3d5/2 and Nb 3d5/2. Surface morphologies evolution controlled by Vb could be observed. Furthermore, X-ray diffraction patterns reveal that these films show a（111） preferred orientation. Moreover, mechanical property and corrosion behavior of ZrNbAlN films were characterized by nanoindentation test and corrosion test, respectively. A maximum value of 21.85 GPa at-70 V occurs in the ZrNbAlN- bronze system, which outperforms uncoated bronze. Corrosion experiments in 0.5 mol/L NaCl and 0.5 mol/L HCl solution show that corrosion potential and corrosion current are dependent on Vb, and better anti-corrosion property could be obtained at-90 V.展开更多
Effect of graphene nanoplatelets(GNPs)addition on mechanical properties of magnesium–10wt%Titanium(Mg–10Ti)alloy is investigated in current work.The Mg-(10Ti+0.18GNPs)composite was synthesized using the semi powder ...Effect of graphene nanoplatelets(GNPs)addition on mechanical properties of magnesium–10wt%Titanium(Mg–10Ti)alloy is investigated in current work.The Mg-(10Ti+0.18GNPs)composite was synthesized using the semi powder metallurgy method followed by hot extrusion.Microstructural characterization results revealed the uniform distribution of reinforcement(Ti+GNPs)particles in the matrix,therefore(Ti+GNPs)particles act as an effective reinforcing filler to prevent the deformation.Room temperature tensile results showed that the addition of Ti+GNPs to monolithic Mg lead to increase in 0.2%yield strength(0.2%YS),ultimate tensile strength(UTS),and failure strain.Scanning Electron Microscopy(SEM),Energy-Dispersive X-ray Spectroscopy(EDS)and X-Ray Diffraction(XRD)were used to investigate the surface morphology,elemental dispersion and phase analysis,respectively.展开更多
Outstanding mechanical properties of graphene nanoplatelets(GNPs)make them ideal reinforcement for mass production of composites.In this research,the composites were fabricated by stir-casting method.GNPs were added i...Outstanding mechanical properties of graphene nanoplatelets(GNPs)make them ideal reinforcement for mass production of composites.In this research,the composites were fabricated by stir-casting method.GNPs were added in 1.5 and 3.0 wt.%into Mg–3wt.%Al–1wt.%Zn(AZ31)magnesium alloy.As cast ingots were preheated for one hour and extruded at 350℃ with extrusion ratio of 5.2:1.As extruded AZ31-GNPs composites were micro-structurally characterized with X-ray diffraction,optical microscopy and scanning electron microscopy.Vickers microhardness of synthesized materials was investigated both in parallel and perpendicular to extrusion directions.Room temperature mechanical testing revealed that with increasing GNP’s content,tensile fracture strain was remarkably increased without significant compromise in tensile strength.Furthermore,as extruded AZ31-3GNPs composites were subjected to tensile testing at temperatures ranging from 75℃ to 300℃ with initial strain rate of 2×10^(−3)s^(−1) to evaluate high temperature formability of composite.It was found that like CNTs,GNPs also have the potential to sustain tensile strength at high temperatures.展开更多
Rechargeable magnesium ion batteries are potential candidates to replace the lithium ion batteries due to their high volumetric energy density,dendrite free cycling,and low costs.In present work,we have critically rev...Rechargeable magnesium ion batteries are potential candidates to replace the lithium ion batteries due to their high volumetric energy density,dendrite free cycling,and low costs.In present work,we have critically reviewed the recent advances made in the field of cathode materials development to achieve the high reversible capacities and working potentials.In first part,carbon-based cathodes such as fluorinedoped graphene nanosheets and graphite fluoride(CF0.8)are discussed in terms of compatibilities of pos让ive electrode materials and electrolyte solutions for rechargeable magnesium-ion batteries.Whereas,the second part of this review focuses on crystal structure of vanadium oxide and its capability to accommodate the Mg^2+ions.Likewise,electrochemical performance of selected vanadium oxide based cathodes including VO2(B),FeVO4.0.9H2(X Mc)2.5+yVO9+δ,RFC/V2O5 and V2O5/Graphene composite,are discussed at different temperatures.To support the future research on magnesium ion batteries,particularly positive electrode material developments,several innovative research directions are proposed.展开更多
In this study,the effect of micron-sized titanium and aluminum addition on the microstructural,mechanical and work-hardening behavior of pure Mg is investigated.Pure Mg reinforced with 10%Ti and 10%Ti-1%Al particulate...In this study,the effect of micron-sized titanium and aluminum addition on the microstructural,mechanical and work-hardening behavior of pure Mg is investigated.Pure Mg reinforced with 10%Ti and 10%Ti-1%Al particulates were synthesized through semi-powder metallurgy route followed by hot extrusion.Semi-powder metallurgy appears to be promising approach for the synthesis of Mg based composite,as it is free of ball milling.Tensile results indicate that the direct addition of micron-sized 10wt.%titanium particulates to pure Mg,caused an improvement in elastic modulus,0.2%yield strength,ultimate tensile strength,and failure strain(+72%;+41%;+29%;and+79%respectively).The addition of micron-sized 10wt.%titanium particles along with 1.0wt.%Al particles to pure Mg,resulted in an enhancement in elastic modulus,0.2%yield strength,ultimate tensile strength,and failure strain(+74%;+56%;+45%;and+241%respectively).Besides tensile test,Vickers hardness and work-hardening behavior of prepared composites were also examined.Impressive failure strain of Mg-10Ti-1Al composite can be attributed to the better compatibility of Ti particulates with Mg due to presence of alloying element Al.展开更多
A CoCrFeMnNi high-entropy alloy with a high content of carbon was synthesized,and its hot deformation behavior was studied at the temperatures 800-1000℃at the strain rates ranging from 0.001 to 0.1s^-1.As-prepared al...A CoCrFeMnNi high-entropy alloy with a high content of carbon was synthesized,and its hot deformation behavior was studied at the temperatures 800-1000℃at the strain rates ranging from 0.001 to 0.1s^-1.As-prepared alloy is a face-centered cubic-structured solid solution,with a large amount of carbides residing at grain boundaries.True stress-strain curves were employed to develop the constitutive equation of apparent activation energy.The apparent activation energy(Q)was found to be 423 kJ mol^-1,indicating a dynamic flow softening behaviThe size of dynamic recrystallized(DRXed)grains increases with increasing the temperature or decreasing the strain rate.A processing map was sketched on the basis of the flow stress.The temperature range of 900-1000℃and 10^-3-10^-2 6 s^-1 strain rate were found to be the optimum hot-forging parameter.With increasing temperature or decreasing strain rate,the volume fraction of fine carbides(≤1μm)increases.A lot of coarse carbides can be found in the matrix after deformation at 800℃,which leads to a high hardness value of 345 HV.The carbides after deformation at 1000℃are mainly nano-sized M7C3 and M23C6,which can promote the nucleation of DRX.展开更多
Coating of graphene and graphene/polymer composites on metals improves the corrosion resistance of metal substrates.On other hand,graphene embedded inside metal(especially Mg)matrices increases or decreases corrosion,...Coating of graphene and graphene/polymer composites on metals improves the corrosion resistance of metal substrates.On other hand,graphene embedded inside metal(especially Mg)matrices increases or decreases corrosion,is a crucial factor and must be explored.In present study,electrochemical behaviors of magnesium alloys(AZ31 and AZ61)and their composites reinforced with graphene nanoplatelets(GNPs)were carried out in 3.5%NaCl solution by polarization method.The surface morphology of composites before and after corrosion tests were analyzed using scanning electron microscopy.Experimental results revealed that presence of graphene nanoplatelets in different matrices decrease corrosion resistance of composites.This may be attributed to presence of graphene nanoplatelets which activates the corrosion of magnesium/alloys due to the occurrence of galvanic corrosion and this effect increases with increasing graphene nanoplatelets content.Further,an appropriate model describing the corrosion mechanism was proposed.展开更多
High-temperature compressive deformation behaviors of Mg–6Zn–1.5Y–0.5Ce–0.4Zr alloy were investigated at temperatures and strain rates ranging from 523 to 673 K and from 0.001 to 1 s~(-1),respectively.The studied ...High-temperature compressive deformation behaviors of Mg–6Zn–1.5Y–0.5Ce–0.4Zr alloy were investigated at temperatures and strain rates ranging from 523 to 673 K and from 0.001 to 1 s~(-1),respectively.The studied alloy was mainly composed ofα-Mg,Mg_(3)Zn_(6)Y(I phase),Mg–Zn–Ce and Mg_(3)Zn_(3)Y_(2)(W phase).The constitutive equation of Mg alloy was obtained,and the apparent activation energy(Q)was determined as 200.44 k J/mol,indicating that rare earth phase increases the difficulty of deformation.The work hardening involves three stages:(1)linear hardening stage;(2)strain hardening stage;and(3)softening and steady-state stage.During these three stages,the dislocation aggregation and tangling,dynamic recovery and recrystallization occur sequentially.To characterize the dynamic recrystallization(DRX)volume fraction,the DRX kinetics was investigated using the Avrami-type equation.The deformation mechanism of magnesium alloy under different Zener–Hollomon parameter(Z)value conditions was also studied.At high Z values and intermediate conditions,dislocations rapidly generate and pile up in the alloy.Recrystallization is hardly seen at this time.At low Z condition,the DRX occurs in the alloy.展开更多
Magnesium-lithium hybrid ion batteries have emerged as a new class of energy storage systems owing to dendrite free cycling of magnesium anode and possibility of practice of numerous conventional lithium cathodes.In p...Magnesium-lithium hybrid ion batteries have emerged as a new class of energy storage systems owing to dendrite free cycling of magnesium anode and possibility of practice of numerous conventional lithium cathodes.In present work,we used hybrid ion strategy to analyze the performance of lithium titanate based lithium cathode,magnesium metal anode,and all-phenyl complex(APC)electrolytes at different temperatures(25℃,10℃,0℃,-10℃,and-20℃).The hybrid ion battery exhibited excellent rate performance(228 m Ah g^(-1)/20 m A g^(-1) and 163 mAh g^(-1)/1000 mA g^(-1))with stable voltage plateaus at 0.90 and 0.75 V,which corresponds to specific energy of 178 Wh kg^(-1) at room temperature(25℃).Experimental results revealed that APC-THF solutions have strong potential to suppress the freezing of electrolyte solutions owing to low boiling point of THF.The low temperature electrochemical testing revealed the reversible capacities of 213.4,165.5,143.8,133.2 and 78.56 mAh g^(-1) at 25,10,0,-10,and-20℃,respectively.Furthermore,ex-situ XRD,SEM,and EIS tests were carried out to understand the reaction kinetics of both Mg2+and Li+ions inside the lithium titanate cathode.We hope this work will shed light on low temperature prospective of electrochemical devices for use in cold environments.展开更多
Gastropods,a mollusk class including slugs and snails,represent an extraordinarily diverse and ecologically significant group of organisms featuring the largest class of invertebrates.They can be classified as aquatic...Gastropods,a mollusk class including slugs and snails,represent an extraordinarily diverse and ecologically significant group of organisms featuring the largest class of invertebrates.They can be classified as aquatic and terrestrial animals having coiled shells,although some species have reduced or absent shells.Their unique body structure includes a muscular foot for locomotion,a visceral mass containing essential organs,and a distinct head region with sensory organs such as tentacles and eyes.They are used to secrete a complex mixture of glycoproteins,enzymes,peptides,mucus and other bioactive compounds,namely slime,which represents a tool to allow locomotion,protection,and interaction within different habitats.The biological activities of the slime have attracted considerable interest due to their diverse and potentially valuable properties ranging from defense mechanisms to potential therapeutic applications in wound healing,antimicrobial therapy,management of inflammation,and neurological disorders.This review aims at exploring the beneficial effects of snail and slug slime focusing,in particular,on the improvement of the biological processes underlying them.Continued exploration of the intricate components of these slimy secretions promises to discover new bioactive molecules with diverse applications in various scientific and industrial fields.展开更多
文摘This paper presents a novel blockchain-embedded cybersecurity framework for industrial solar power systems,integrating immutable machine learning(ML)with distributed ledger technology.Our contribution focused on three factors,Quantum-resistant feature engineering using theUNSW-NB15 dataset adapted for solar infrastructure anomalies.An enhanced Light Gradient Boosting Machine(LightGBM)classifier with blockchain-validated decision thresholds,and A cryptographic proof-of-threat(PoT)consensus mechanism for cyber attack verification.The proposed Immutable LightGBM model with majority voting and cryptographic feature encoding achieves 96.9% detection accuracy with 0.97 weighted average of precision,recall and F1-score,outperforming conventional intrusion detection systems(IDSs)by 12.7% in false positive reduction.The blockchain layer demonstrates a 2.4-s average block confirmation time with 256-bit SHA-3 hashing,enabling real-time threat logging in photovoltaic networks.Experimental results improve in attack traceability compared to centralized security systems,establishing new benchmarks for trustworthy anomaly detection in smart grid infrastructures.This study also compared traditional and hybrid ML based blockchian driven IDSs and attained better classification results.The proposed framework not only delivers a resilient,adaptable threat mitigation system(TMS)for Industry 4.0 solar powered infrastructure but also attains high explainability,scalability with tamper-proof logs,and remarkably exceptional ability of endurance to cyber attacks.
基金funded by the National Natural Science Foundation of China (Nos. 51971042, 51901028)the Fundamental Research Funds for the Central Universities Project, China (No. 2021CDJQY-038)the Chongqing Academician Special Fund, China (Nos. cstc2018jcyj-yszxX0007, cstc2019yszx-jcyjX0004)
文摘A novel continuous plastic process employed on AZ31 Mg alloy called closed forging extrusion(CFE)was presented.The optical microscopy,scanning electron microscopy,electron back-scatter diffraction and tensile and compressive tests were employed to investigate the microstructure evolution and strengthening mechanism.The results indicated that the CFE-process can promote dynamic recrystallization(DRX),eliminate the coarsen unDRXed grain regions,refine the grains effectively,and improve the strength,plasticity and anisotropy of the alloy.The grain refinement was mainly attributed to the stress,which facilitated the nucleation of recrystallization and refined the microstructure via the CFE.The fully DRXed ultrafine grained structure improved the strength and plasticity simultaneously.After 60 s closed forging and continuous extrusion,the alloy exhibits relatively high TYS,UTS,CYS,elongation and yield asymmetry of 305 MPa,337 MPa,295 MPa,27%and 0.97,respectively.
基金Acknowledgments The authors acknowledge the financial support from the Guangdong Major Project of Basic and Applied Basic Research,China(No.2020B0301030006)the National Natural Science Foundation of China(Nos.52171133,52171103)+1 种基金the“111 Project”by the Ministry of Education of China(No.B16007)Fundamental Research Fund of Central Universities in China(No.2018CDJDCL0019)。
文摘Mg−9Al−1Zn(AZ91)magnesium matrix composites reinforced by Ti−6Al−4V(TC4)particles were successfully prepared via powder metallurgical method.The yield strength(YS),ultimate tensile strength(UTS),and elongation(EL)showed a mountain-like tendency with the increase of the TC4 content.The mechanical properties of AZ91 magnesium matrix composites reached the optimal point with TC4 content of 10 wt.%,realizing YS,UTS,and EL of 335 MPa,370 MPa,and 6.4%,respectively.The improvement of mechanical properties can be attributed to the effective load transfer from the magnesium matrix to the TC4 particles,dislocations associated with the difference in the coefficient of thermal expansion,good interfacial bonding between the Mg matrix and TC4 particles,and grain refinement strengthening.
基金Project(50725413)supported by the National Natural Science Foundation of ChinaProject(2010BB4290)supported by Natural Science Foundation Project of CQ CSTC,China
文摘Nano-scaled ZrNbAlN films with different negative bias voltages（Vb） were deposited on bronze substrate and Si（100） wafers by a reactive unbalanced magnetron sputtering technique. Composition and structure properties were characterized by X-ray photoelectron spectroscopy and X-ray diffraction. It is found that mole concentrations of Zr and Nb are affected by Vb, which leads to the increase of binding energy of N 1s and Al 2p and decrease of binding energy of Zr 3d5/2 and Nb 3d5/2. Surface morphologies evolution controlled by Vb could be observed. Furthermore, X-ray diffraction patterns reveal that these films show a（111） preferred orientation. Moreover, mechanical property and corrosion behavior of ZrNbAlN films were characterized by nanoindentation test and corrosion test, respectively. A maximum value of 21.85 GPa at-70 V occurs in the ZrNbAlN- bronze system, which outperforms uncoated bronze. Corrosion experiments in 0.5 mol/L NaCl and 0.5 mol/L HCl solution show that corrosion potential and corrosion current are dependent on Vb, and better anti-corrosion property could be obtained at-90 V.
基金The present work was supported by the National Natural Science Funds of China(No.50725413)the Ministry of Science and Technology of China(MOST)(No.2010DFR50010 and 2011FU125Z07)Chongqing Science and Technology Commission(CSTC2013jcyjC60001).
文摘Effect of graphene nanoplatelets(GNPs)addition on mechanical properties of magnesium–10wt%Titanium(Mg–10Ti)alloy is investigated in current work.The Mg-(10Ti+0.18GNPs)composite was synthesized using the semi powder metallurgy method followed by hot extrusion.Microstructural characterization results revealed the uniform distribution of reinforcement(Ti+GNPs)particles in the matrix,therefore(Ti+GNPs)particles act as an effective reinforcing filler to prevent the deformation.Room temperature tensile results showed that the addition of Ti+GNPs to monolithic Mg lead to increase in 0.2%yield strength(0.2%YS),ultimate tensile strength(UTS),and failure strain.Scanning Electron Microscopy(SEM),Energy-Dispersive X-ray Spectroscopy(EDS)and X-Ray Diffraction(XRD)were used to investigate the surface morphology,elemental dispersion and phase analysis,respectively.
基金the National Natural Science Foundation of China(Projects 51531002,51474043,51571043)Fundamental Research Funds for the Central Universities(Grant 106112015CDJZR135515)Chongqing Municipal Government(CSTC2013JCYJC60001,CEC project,Two River Scholar Project andThe Chief Scientist Studio Project).
文摘Outstanding mechanical properties of graphene nanoplatelets(GNPs)make them ideal reinforcement for mass production of composites.In this research,the composites were fabricated by stir-casting method.GNPs were added in 1.5 and 3.0 wt.%into Mg–3wt.%Al–1wt.%Zn(AZ31)magnesium alloy.As cast ingots were preheated for one hour and extruded at 350℃ with extrusion ratio of 5.2:1.As extruded AZ31-GNPs composites were micro-structurally characterized with X-ray diffraction,optical microscopy and scanning electron microscopy.Vickers microhardness of synthesized materials was investigated both in parallel and perpendicular to extrusion directions.Room temperature mechanical testing revealed that with increasing GNP’s content,tensile fracture strain was remarkably increased without significant compromise in tensile strength.Furthermore,as extruded AZ31-3GNPs composites were subjected to tensile testing at temperatures ranging from 75℃ to 300℃ with initial strain rate of 2×10^(−3)s^(−1) to evaluate high temperature formability of composite.It was found that like CNTs,GNPs also have the potential to sustain tensile strength at high temperatures.
基金This research was supported by National Natural Science Foundation of China(51601073)Jiangsu Distinguished Professor Project(1064901601)+1 种基金Jiangsu Provincial Six Talent Peaks Project(1062991801)Jiangsu University of Science and Technology Research Start-Up Fund(1062921905).
文摘Rechargeable magnesium ion batteries are potential candidates to replace the lithium ion batteries due to their high volumetric energy density,dendrite free cycling,and low costs.In present work,we have critically reviewed the recent advances made in the field of cathode materials development to achieve the high reversible capacities and working potentials.In first part,carbon-based cathodes such as fluorinedoped graphene nanosheets and graphite fluoride(CF0.8)are discussed in terms of compatibilities of pos让ive electrode materials and electrolyte solutions for rechargeable magnesium-ion batteries.Whereas,the second part of this review focuses on crystal structure of vanadium oxide and its capability to accommodate the Mg^2+ions.Likewise,electrochemical performance of selected vanadium oxide based cathodes including VO2(B),FeVO4.0.9H2(X Mc)2.5+yVO9+δ,RFC/V2O5 and V2O5/Graphene composite,are discussed at different temperatures.To support the future research on magnesium ion batteries,particularly positive electrode material developments,several innovative research directions are proposed.
基金The present work was supported by the National Natural Science Funds of China(No.50725413)the Ministry of Science and Technology of China(MOST)(No.2010DFR50010 and 2011FU125Z07)Chongqing Science and Technology Commission(CSTC2013JCYJC60001).
文摘In this study,the effect of micron-sized titanium and aluminum addition on the microstructural,mechanical and work-hardening behavior of pure Mg is investigated.Pure Mg reinforced with 10%Ti and 10%Ti-1%Al particulates were synthesized through semi-powder metallurgy route followed by hot extrusion.Semi-powder metallurgy appears to be promising approach for the synthesis of Mg based composite,as it is free of ball milling.Tensile results indicate that the direct addition of micron-sized 10wt.%titanium particulates to pure Mg,caused an improvement in elastic modulus,0.2%yield strength,ultimate tensile strength,and failure strain(+72%;+41%;+29%;and+79%respectively).The addition of micron-sized 10wt.%titanium particles along with 1.0wt.%Al particles to pure Mg,resulted in an enhancement in elastic modulus,0.2%yield strength,ultimate tensile strength,and failure strain(+74%;+56%;+45%;and+241%respectively).Besides tensile test,Vickers hardness and work-hardening behavior of prepared composites were also examined.Impressive failure strain of Mg-10Ti-1Al composite can be attributed to the better compatibility of Ti particulates with Mg due to presence of alloying element Al.
基金financially supported by the National Natural Science Foundation of China (No.51601022)the National Key Research and Development plan of China (No.2016YFB0700302)the Science and Technology Planning Project of Hunan Province of China (No.2015SK1002-1)
文摘A CoCrFeMnNi high-entropy alloy with a high content of carbon was synthesized,and its hot deformation behavior was studied at the temperatures 800-1000℃at the strain rates ranging from 0.001 to 0.1s^-1.As-prepared alloy is a face-centered cubic-structured solid solution,with a large amount of carbides residing at grain boundaries.True stress-strain curves were employed to develop the constitutive equation of apparent activation energy.The apparent activation energy(Q)was found to be 423 kJ mol^-1,indicating a dynamic flow softening behaviThe size of dynamic recrystallized(DRXed)grains increases with increasing the temperature or decreasing the strain rate.A processing map was sketched on the basis of the flow stress.The temperature range of 900-1000℃and 10^-3-10^-2 6 s^-1 strain rate were found to be the optimum hot-forging parameter.With increasing temperature or decreasing strain rate,the volume fraction of fine carbides(≤1μm)increases.A lot of coarse carbides can be found in the matrix after deformation at 800℃,which leads to a high hardness value of 345 HV.The carbides after deformation at 1000℃are mainly nano-sized M7C3 and M23C6,which can promote the nucleation of DRX.
基金supported by the National Natural Science Foundation of China(Projects 51531002,51474043,51571043)Fundamental Research Funds for the Central Universities(Grant 106112015CDJZR135515)Chongqing Municipal Government(CSTC2013JCYJC60001,CEC project,Two River Scholar Project and The Chief Scientist Studio Project).
文摘Coating of graphene and graphene/polymer composites on metals improves the corrosion resistance of metal substrates.On other hand,graphene embedded inside metal(especially Mg)matrices increases or decreases corrosion,is a crucial factor and must be explored.In present study,electrochemical behaviors of magnesium alloys(AZ31 and AZ61)and their composites reinforced with graphene nanoplatelets(GNPs)were carried out in 3.5%NaCl solution by polarization method.The surface morphology of composites before and after corrosion tests were analyzed using scanning electron microscopy.Experimental results revealed that presence of graphene nanoplatelets in different matrices decrease corrosion resistance of composites.This may be attributed to presence of graphene nanoplatelets which activates the corrosion of magnesium/alloys due to the occurrence of galvanic corrosion and this effect increases with increasing graphene nanoplatelets content.Further,an appropriate model describing the corrosion mechanism was proposed.
基金financially supported by the National Key R&D Program of China(2016YFB0301100)the Natural Science Foundation of Chongqing,China(cstc2019jcyj-msxmX0505)the support of the“111 Project”(B16007)by the Ministry of Education and Fundamental Research Fund of Central Universities in China(Grant No.2018CDJDCL0019)。
文摘High-temperature compressive deformation behaviors of Mg–6Zn–1.5Y–0.5Ce–0.4Zr alloy were investigated at temperatures and strain rates ranging from 523 to 673 K and from 0.001 to 1 s~(-1),respectively.The studied alloy was mainly composed ofα-Mg,Mg_(3)Zn_(6)Y(I phase),Mg–Zn–Ce and Mg_(3)Zn_(3)Y_(2)(W phase).The constitutive equation of Mg alloy was obtained,and the apparent activation energy(Q)was determined as 200.44 k J/mol,indicating that rare earth phase increases the difficulty of deformation.The work hardening involves three stages:(1)linear hardening stage;(2)strain hardening stage;and(3)softening and steady-state stage.During these three stages,the dislocation aggregation and tangling,dynamic recovery and recrystallization occur sequentially.To characterize the dynamic recrystallization(DRX)volume fraction,the DRX kinetics was investigated using the Avrami-type equation.The deformation mechanism of magnesium alloy under different Zener–Hollomon parameter(Z)value conditions was also studied.At high Z values and intermediate conditions,dislocations rapidly generate and pile up in the alloy.Recrystallization is hardly seen at this time.At low Z condition,the DRX occurs in the alloy.
基金JUST Research Start-Up Fund(1062921905)supported。
文摘Magnesium-lithium hybrid ion batteries have emerged as a new class of energy storage systems owing to dendrite free cycling of magnesium anode and possibility of practice of numerous conventional lithium cathodes.In present work,we used hybrid ion strategy to analyze the performance of lithium titanate based lithium cathode,magnesium metal anode,and all-phenyl complex(APC)electrolytes at different temperatures(25℃,10℃,0℃,-10℃,and-20℃).The hybrid ion battery exhibited excellent rate performance(228 m Ah g^(-1)/20 m A g^(-1) and 163 mAh g^(-1)/1000 mA g^(-1))with stable voltage plateaus at 0.90 and 0.75 V,which corresponds to specific energy of 178 Wh kg^(-1) at room temperature(25℃).Experimental results revealed that APC-THF solutions have strong potential to suppress the freezing of electrolyte solutions owing to low boiling point of THF.The low temperature electrochemical testing revealed the reversible capacities of 213.4,165.5,143.8,133.2 and 78.56 mAh g^(-1) at 25,10,0,-10,and-20℃,respectively.Furthermore,ex-situ XRD,SEM,and EIS tests were carried out to understand the reaction kinetics of both Mg2+and Li+ions inside the lithium titanate cathode.We hope this work will shed light on low temperature prospective of electrochemical devices for use in cold environments.
基金FAR 2020,2021 Cataldi,FAR 2020,2021 Zara and also supported by MUR National Innovation Ecosystem-Recovery and Resilience Plan(PNRR)Italy。
文摘Gastropods,a mollusk class including slugs and snails,represent an extraordinarily diverse and ecologically significant group of organisms featuring the largest class of invertebrates.They can be classified as aquatic and terrestrial animals having coiled shells,although some species have reduced or absent shells.Their unique body structure includes a muscular foot for locomotion,a visceral mass containing essential organs,and a distinct head region with sensory organs such as tentacles and eyes.They are used to secrete a complex mixture of glycoproteins,enzymes,peptides,mucus and other bioactive compounds,namely slime,which represents a tool to allow locomotion,protection,and interaction within different habitats.The biological activities of the slime have attracted considerable interest due to their diverse and potentially valuable properties ranging from defense mechanisms to potential therapeutic applications in wound healing,antimicrobial therapy,management of inflammation,and neurological disorders.This review aims at exploring the beneficial effects of snail and slug slime focusing,in particular,on the improvement of the biological processes underlying them.Continued exploration of the intricate components of these slimy secretions promises to discover new bioactive molecules with diverse applications in various scientific and industrial fields.
