As battery technology evolves and demand for efficient energy storage solutions,aqueous zinc ion batteries(AZIBs)have garnered significant attention due to their safety and environmental benefits.However,the stability...As battery technology evolves and demand for efficient energy storage solutions,aqueous zinc ion batteries(AZIBs)have garnered significant attention due to their safety and environmental benefits.However,the stability of cathode materials under high-voltage conditions remains a critical challenge in improving its energy density.This review systematically explores the failure mechanisms of high-voltage cathode materials in AZIBs,including hydrogen evolution reaction,phase transformation and dissolution phenomena.To address these challenges,we propose a range of advanced strategies aimed at improving the stability of cathode materials.These strategies include surface coating and doping techniques designed to fortify the surface properties and structure integrity of the cathode materials under high-voltage conditions.Additionally,we emphasize the importance of designing antioxidant electrolytes,with a focus on understanding and optimizing electrolyte decomposition mechanisms.The review also highlights the significance of modifying conductive agents and employing innovative separators to further enhance the stability of AZIBs.By integrating these cutting-edge approaches,this review anticipates substantial advancements in the stability of high-voltage cathode materials,paving the way for the broader application and development of AZIBs in energy storage.展开更多
Highly porous Mg-Ca-Zn-Co alloy scaffolds for tissue engineering applications were produced by powder metallurgy based space holder-water leaching method.Mg-Ca-Zn-Co alloy foam can be used as a scaffold material in ti...Highly porous Mg-Ca-Zn-Co alloy scaffolds for tissue engineering applications were produced by powder metallurgy based space holder-water leaching method.Mg-Ca-Zn-Co alloy foam can be used as a scaffold material in tissue engineering.Carbamide was used as a space holder material.Fluoride conversion coating was synthesized on the alloy by immersion treatment in hydrofluoric acid(HF).Increasing Zn content of the alloy increased the elastic modulus.Ca addition prevented the oxidation of the specimens during sintering.Electrochemical corrosion behaviour of the specimens was examined in simulated body fluid.Corrosion rate decreased with Zn addition from1.0%up to3.0%(mass fraction)and then increased.Mass loss of the specimens initially decreased with Zn addition up to about3%and then increased.Fluoride conversion coating increased the corrosion resistance of the specimens.展开更多
An Al2O3-TiB2 nanocomposite was successfully synthesized by ball milling of Al, TiO2 and two B source materials of B2O3 （system （1）） and H3BO3 （system （2））. Phase identification of the milled samples was exami...An Al2O3-TiB2 nanocomposite was successfully synthesized by ball milling of Al, TiO2 and two B source materials of B2O3 （system （1）） and H3BO3 （system （2））. Phase identification of the milled samples was examined by Xray diffraction. The morphology and microstructure of the milled powders were monitored by scanning electron microscopy and transmission electron microscopy. It was found that the formation of this composite was completed after 15 and 30 h of milling time in systems （1） and （2）, respectively. More milling energy was required for the formation of this composite in system （2） due to the lubricant properties of HaBO3 and also its decomposition to HBO2 and B2O3 during milling. On the basis of X-ray diffraction patterns and thermodynamic calculations, this composite was formed by highly exothermic mechanically induced self-sustaining reactions （MSR） in both systems. The MSR mode took place around 9 h and 25 h of milling in systems （1） and （2）, respectively. At the end of milling （15 h for system （1） and 30 h for system （2）） the grain size of about 35-50 nm was obtained in both systems.展开更多
Powder metallurgical Cu-Ti alloys with different titanium additions produced by hot pressing were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and hardness, wear and b...Powder metallurgical Cu-Ti alloys with different titanium additions produced by hot pressing were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and hardness, wear and bending tests. The addition of titanium to copper caused the formation of different intermetallic layers around titanium particles. The titanium content of the intermetallics decreased from the center of the particle to the copper matrix. The hardness, wear resistance, and bending strength of the materials increased with increasing Ti content, whereas strain in the bending test decreased. Worn surface analyses showed that different wear mechanisms were active during the wear test of specimens with different chemical compositions. Changes in the properties of the materials with titanium addition were explained by the high hardness of different Cu-Ti intermetallic phases.展开更多
Joining of dissimilar aluminium-copper is an emerging area of interest for both research and industry due to its complex nature.Friction stir welding was attempted to evaluate the joint strength without offset at the ...Joining of dissimilar aluminium-copper is an emerging area of interest for both research and industry due to its complex nature.Friction stir welding was attempted to evaluate the joint strength without offset at the butt line between AA6063 to HCP copper sheet under different combination of rotational speed of 800 and 1000 r/min and travel speed of 20 and 40 mm/min.Material flow was studied in detail for different combinations of parameters with optical microscopy and elemental mapping by energy dispersive X-ray spectroscopy（EDS）.The results were correlated with the microstructural characteristics and formation of intermetallics at the bond interface using microhardness test and X-ray diffraction（XRD） technique.Material flow clearly suggests that energy input at 800 r/min and 20 mm/min is sufficient to plasticize both the materials with formation of higher amount of thermodynamically stable and hard intermetallic phases Al4Cu9 and Al Cu4（slower cooling rate of 88 K/s） than that at 800 r/min and 40 mm/min（faster cooling rate of 154 K/s）,attributed maximum joint strength（~78.6% of aluminium base metal）.展开更多
Traditional synthetic methodologies are confronted with great challenges to fabricate complex nanomaterials with delicate design,high efficiency and excellent sustainability.During the past decade,bio-inspired synthes...Traditional synthetic methodologies are confronted with great challenges to fabricate complex nanomaterials with delicate design,high efficiency and excellent sustainability.During the past decade,bio-inspired synthesis has been extensively applied as an effective and efficient strategy for the fabrication of nanomaterials and nanostructures.Mimicking electrode materials at nanoscale in the aspect of either structure or functionality has been receiving surging interest because of their incomparable advantages and outperforming properties.In this review,we summarize the recent progresses on bio-inspired synthesis of nanomaterials and smart structures in the field of energy storage and conversion.Firstly,an overall introduction of bio-inspired synthetic strategies will be presented,with focus on the biotemplates and bio-resources.Following that,a library of complex mimicking structures featured by high-order,hierarchical porosity,or bionic function are introduced,with discussion on their chemical and physical properties associated with the structure.The enhanced electrochemical properties such as energy density,cycling stability,etc.in different electrochemical systems will be also discussed.At last,we will expand the perspectives regarding the advantages and limitations of bioinspired strategy and possible solutions in the future.展开更多
In this study, resistance spot weldability of 180 grade bake hardening steel （BH180）, 7123 grade interstitial free steel （IF7123） and 304 grade austenitic stainless steel （AISI304L） with each other was investiga...In this study, resistance spot weldability of 180 grade bake hardening steel （BH180）, 7123 grade interstitial free steel （IF7123） and 304 grade austenitic stainless steel （AISI304L） with each other was investigated. In the joining process, electrode pressure and weld current were kept constant and six different weld time were chosen. Microstructure, microhardness, tensile-shear properties and fracture types of resistance spot welded joints were examined. In order to characterize the metallurgical structure of the welded joint, the microstructural profile was developed, and the relationship between mechanical properties and microstructure was determined. The change of weld time, nugget diameter, the HAZ （heat affected zone） width and the electrode immersion depth were also investigated. Welded joints were examined by SEM （scanning electron microscopy） images of fracture surface. As a result of the experiment, it was determined that with increasing weld time, tensile shear load bearing capacity （TLBC） increased with weld time up to 25 cycle and two types of tearing occurred. It was also determined that while the failure occurred from IF side at the BHIS0＋IF7123 joint, it occurred from the BH180 side at the BHIS0＋AISI304L joint.展开更多
To study the formation of detrimental phases under the sulfur gas impurity to the long-term degradation in the cathode material,the classic cathode material,(La_(0.8)Sr_(0.2))_(0.95)MnO_(3)(LSM),was prepared,sintered,...To study the formation of detrimental phases under the sulfur gas impurity to the long-term degradation in the cathode material,the classic cathode material,(La_(0.8)Sr_(0.2))_(0.95)MnO_(3)(LSM),was prepared,sintered,and annealed at 800,900,and 1000℃ in the sulfur-containing atmospheres,respectively.Through X-ray diffraction,scanning electron microscope,and transmission electron microscopy techniques,as well as the computer coupling of phase diagrams and thermochemistry methodology,the secondary phases,especially the detrimental ones,under different conditions were predicted and experimentally verified correspondingly.Furthermore,sulfur poisoning results indicate that the accelerated tests might have degradation mechanisms different from actual operation conditions.More importantly,comprehensive comparisons among various impurity-containing conditions were also made to recommend better operation parameters.展开更多
One of the thrust areas of research is to find an alternative fuel to meet the increasing demand for energy.Glucose is a good source of alternative fuel for clean energy and is easily available in abundance from both ...One of the thrust areas of research is to find an alternative fuel to meet the increasing demand for energy.Glucose is a good source of alternative fuel for clean energy and is easily available in abundance from both naturally occurring plants and industrial processes.Electrochemical oxidation of glucose in fuel cell requires high electro-catalytic surface of the electrode to produce the clean electrical energy w ith minimum energy losses in the cell.Pt and Pt based alloys exhibit high electro-catalytic properties but they are expensive.For energy synthesis at economically cheap price,non Pt based inexpensive high electro catalytic material is required.Electro synthesized Zn O-Al2O3composite is found to exhibit high electro-catalytic properties for glucose oxidation.The Cyclic Voltammetry and Chronoamperometry curves reflect that the material is very much comparable to Pt as far as the maximum current and the steady state current delivered from the glucose oxidation are concerned.XRD image confirms the mixed oxide composite.SEM images morphology show increased 3D surface areas at higher magnification.This attributed high current delivered from electrochemical oxidation of glucose on this electrode surface.展开更多
A promising friction material, Iron -based friction material, was prepared by powder metallurgy (PM) processing utilizing hot powder preform forging (near net-shape).The preparation of the product and its characteriza...A promising friction material, Iron -based friction material, was prepared by powder metallurgy (PM) processing utilizing hot powder preform forging (near net-shape).The preparation of the product and its characterization are presented in this paper. These products are useful in heavy duty Military Aircraft applications such as AN-32. In order to eliminate costly environmental control systems to protect products during their high temperature processing (as is conventionally practiced employing hydrogen gas), the present investigation relies on carbon (mixed in the brake pad formulation) as reducing agent and high temperature oxidation resistant glassy coating (separately developed) applied over the product’s surface after cold compacting. After conducting an initial characterization such as hardness, density and Pin-on Disc tests, the samples were tested in sub-scale dynamometer under Rejected Take Off conditions. It was observed that the obtained density in the present investigation is higher than the reported density obtained by sintering route, and wear is on the lower side of the range as per the Aeronautical Standards. Optical metallography was used to investigate the microstructure of friction, interface and backing layer. It was observed that the distribution of ingredients in matrix was homogeneous. The results also indicate that the coefficient of friction is more stable, and wear is lower with respect to temperature rise. .展开更多
Polymeric materials especially nanocomposites(Graphene,MXene based)are widely used in food,electronics,biomedical,batteries,energy storage,fuel cells,wastewater treatment,and automotive[1].Nanocomposites are stronger,...Polymeric materials especially nanocomposites(Graphene,MXene based)are widely used in food,electronics,biomedical,batteries,energy storage,fuel cells,wastewater treatment,and automotive[1].Nanocomposites are stronger,lighter,and stiffer and can improve properties such as mechanical strength,electrical conductivity,thermal stability,flame retardancy,surface appearance,optical clarity and chemical resistance.Current research is focusing on nanocomposites applications[1-3],CO_(2)capturing polymers[4],making polymers degradable[5-7]especially developing bio-composites[8]and green composites[9,10]which are degradable。展开更多
Graphene oxide (GO) reduced by Stachys lavandulifolia extract (SLE) was produced and characterised. The anti-corrosion behaviour of epoxy coatings containing GO and rGO nanosheets was investigated. FESEM-EDS, FT-IR, a...Graphene oxide (GO) reduced by Stachys lavandulifolia extract (SLE) was produced and characterised. The anti-corrosion behaviour of epoxy coatings containing GO and rGO nanosheets was investigated. FESEM-EDS, FT-IR, and Raman spectroscopy were used to examine the microstructure and chemical composition of the nanosheets and epoxy coatings. EIS experiment was used to explore the corrosion behaviour of the coatings. The O/C ratio for GO and rGO-SLE was found to be 2.5 and 4.5, indicating a decrease in the carbon content after the reduction of GO, confirming the adsorption of SLE onto the GO nanosheets. The successful reduction of GO in the presence of SLE particles was confirmed by disappearing the C=O peak and a significant decrease in the C-O-C bond intensity. The epoxy/rGO- SLE coatings exhibited the highest double-layer thickness and excellent corrosion resistance compared to neat epoxy and epoxy/GO coatings, emphasizing the significant role of rGO in enhancing the protective performance of epoxy coatings. The highest values for total charge transfer and film resistances and the inhibition efficiency were observed to be 6529 Ω·cm^(2) and 90%, respectively, for the epoxy/rGO-SLE coated steel plate. It was also found that the epoxy/0.15 wt.% rGO-SLE coating demonstrates the best corrosion resistance performance.展开更多
Designing high-performance high-entropy alloys(HEAs)with transformation-induced plasticity(TRIP)or twinning-induced plasticity(TWIP)effects requires precise control over stacking fault energy(SFE)and phase stability.H...Designing high-performance high-entropy alloys(HEAs)with transformation-induced plasticity(TRIP)or twinning-induced plasticity(TWIP)effects requires precise control over stacking fault energy(SFE)and phase stability.However,the vast complexity of multicomponent systems poses a major challenge for identifying promising candidates through conventional experimental or computational methods.A high-throughput CALPHAD framework is developed to identify compositions with potential TWIP/TRIP behaviors in the Cr-Co-Ni and Cr-Co-Ni-Fe systems through systematic screening of stacking fault energy(SFE),FCC phase stability,and FCC-to-HCP transition temperatures(T0).The approach combines TC-Python automation with parallel Gibbs energy calculations across hundreds of thousands of compositions,enabling efficient extraction of metastable FCC-dominant alloys.The high-throughput results find 214 compositions with desired properties from 160,000 candidates.Detailed analysis of the Gibbs energy distributions,phase fraction trends,and temperature-dependent SFE evolution reveals critical insights into the thermodynamic landscape governing plasticity mechanisms in HEAs.The results show that only a narrow region of the compositional space satisfies all screening criteria,emphasizing the necessity of an integrated approach.The screened compositions and trends provide a foundation for targeted experimental validation.Furthermore,this work demonstrates a scalable,composition-resolved strategy for predicting deformation mechanisms in multicomponent alloys and offers a blueprint for integrating thermodynamic screening with mechanistic understanding in HEA design.展开更多
Carbon dioxide enhanced oil recovery(CO_(2)-EOR)technology is used for oil production and CO_(2) storage in reservoirs.Methods are being constantly developed to optimize oil recovery and CO_(2) storage during the CO_(...Carbon dioxide enhanced oil recovery(CO_(2)-EOR)technology is used for oil production and CO_(2) storage in reservoirs.Methods are being constantly developed to optimize oil recovery and CO_(2) storage during the CO_(2) displacement process,especially for low-permeability reservoirs under varying geological conditions.In this study,long-core experiments and trans-scale numerical simulations are employed to examine the characteristics of oil production and CO_(2) storage.Optimal production parameters for the target reservoir are also proposed.The results indicate that maintaining the pressure at 1.04 to 1.10 times the minimum miscible pressure(MMP)and increasing the injection rate can enhance oil production in the early stage of reservoir development.In contrast,reducing the injection rate at the later stages prevents CO_(2) channeling,thus improving oil recovery and CO_(2) storage efficiency.A solution-doubling factor is introduced to modify the calculation method for CO_(2) storage,increasing its accuracy to approximately 90%.Before CO_(2) breakthrough,prioritizing oil production is recommended to maximize the economic benefits of this process.In the middle stage of CO_(2) displacement,decreasing the injection rate optimizes the coordination between oil displacement and CO_(2) storage.Further,in the late stage,reduced pressure and injection rates are required as the focus shifts to CO_(2) storage.展开更多
The pozzolanic activity of coal gangue burned at different burning temperatures was investigated. The burned coal gangue was mixed with portland cement in different proportions （ 20% - 60% ）. The pozzolanic activity...The pozzolanic activity of coal gangue burned at different burning temperatures was investigated. The burned coal gangue was mixed with portland cement in different proportions （ 20% - 60% ）. The pozzolanic activity of coal gangue burned and the hydration products were examined, the compressive strengths of the pastes of the mixtures were tested, and the mechanism of the reaction was discussed. The experimental results slum, that the coal gangue burned at 750 ℃ has the optimum pozzolanic activity, and the burned coal ganguc with SiO2 and Al2 O3 is in an active form. When the coal gangue burned at 750℃ is mixed into portland cement, the content of calcium hydroxide in paste is significantly reduced, while the contents of hydrated calcium silk.ate and hydrated calcium aluminate are increased accordingly, hence resulting in the improvement of the microstructure of mortar. The compressive strength of cement paste decreases with increasing the content of burncd coal gangue. The decease in strength is small in the range of 20% - 30% coal gangue substitution and significant in 30%- 60% substitution.展开更多
Grade A （GA） and high strength steel DH36 ship steels possessing different chemical compositions were used, and strength properties of GA steel and DH36 steel were compared. Additionally, 4 types of dual phase （DP...Grade A （GA） and high strength steel DH36 ship steels possessing different chemical compositions were used, and strength properties of GA steel and DH36 steel were compared. Additionally, 4 types of dual phase （DP） steels with different martensite volume fractions （MVFs） were produced from GA steel by means of heat treatment and they were compared with other steels through conducting mierostructure, microhardness, tensile and impact tests. The fracture surfaces of specimens （DH36, GA and DP steels） exposed to tensile and Charpy impact tests were investigated by scanning electron microscope. Furthermore, it was found that the specimens quenched from 800 and 900℃ had better strength than DH36 steel. The tensile test results indicated that the tensile strength of DP steel water quenched from 900℃ was 3 times that of GA steel and twice that of DH36 steel.展开更多
Zinc coated dual phase 600 steel （DP 600 grade） was investigated, utilisation of which has gradually increased with each passing day in the automotive industry. The adhesive bonding （AB）, resistance spot welding ...Zinc coated dual phase 600 steel （DP 600 grade） was investigated, utilisation of which has gradually increased with each passing day in the automotive industry. The adhesive bonding （AB）, resistance spot welding （RSW）, and adhesive weld bonding （AWB） ioints of the zinc coated DP 600 steel were investigated. Additionally, the zinc coating was removed using HCL acid in order to investigate the effect of the coating. The microstructure, tensile shear strengths, and fracture properties of adhesive bonding （AB）, resistance spot welding （RSW）, and adhesive weld bonding （AWB） joints of the coated and uncoated DP 600 steel were compared. In addition, a mechani cal-electrical-thermal coupled model in a finite element analysis environment was utilised. The thermal profile phe nomenon was calculated by simulating this process. The results of the tensile shear test indicated that the tensile load bearing capacity （TLBC） values of the coated specimens among the three welding methods were higher than those of the uncoated specimens. Additionally, the tensile strength of the AWB joints of the coated and uncoated specimens was higher than that of the AB and RSW joints. It was determined that the fracture behaviours and the deformation caused were different for the three welding methods.展开更多
Friction stir welding （FSW） of 6061 aluminium alloy butt joint was carried out at each rotation speed of 600, 800, 1000, 1200 r/min for two different travel speeds, 80 and 100 mm/min, at a constant probe depth of 1....Friction stir welding （FSW） of 6061 aluminium alloy butt joint was carried out at each rotation speed of 600, 800, 1000, 1200 r/min for two different travel speeds, 80 and 100 mm/min, at a constant probe depth of 1.85 mm. The calculated energy input based on the FSW parameters studied shows that the ultimate tensile strength （UTS） of the butt joint is obtained within a certain range of energy input of 297 kJ to 354 kJ out of total range of energy input studied from 196 kJ to 405 kJ. The fatigue behaviors of high-strength and low-strength joints performed at different stress ratios, i.e., 0.5, 0.3, 0.1, -0.3, -0.5, indicate that the fatigue behaviors of both the welds are sensitive to the microstructural features, such as stir zone （SZ）, thermo mechanically affected zone （TMAZ） and heat affected zone （HAZ）. The observed fatigue strengths were discussed in terms of the microstructure, crack path behavior and fracture surface.展开更多
基金supported by the Exchange Program of Highend Foreign Experts of Ministry of Science and Technology of People’s Republic of China(No.G2023041003L)the Natural Science Foundation of Shaanxi Provincial Department of Education(No.23JK0367)+1 种基金the Scientific Research Startup Program for Introduced Talents of Shaanxi University of Technology(Nos.SLGRCQD2208,SLGRCQD2306,SLGRCQD2133)Contaminated Soil Remediation and Resource Utilization Innovation Team at Shaanxi University of Technology。
文摘As battery technology evolves and demand for efficient energy storage solutions,aqueous zinc ion batteries(AZIBs)have garnered significant attention due to their safety and environmental benefits.However,the stability of cathode materials under high-voltage conditions remains a critical challenge in improving its energy density.This review systematically explores the failure mechanisms of high-voltage cathode materials in AZIBs,including hydrogen evolution reaction,phase transformation and dissolution phenomena.To address these challenges,we propose a range of advanced strategies aimed at improving the stability of cathode materials.These strategies include surface coating and doping techniques designed to fortify the surface properties and structure integrity of the cathode materials under high-voltage conditions.Additionally,we emphasize the importance of designing antioxidant electrolytes,with a focus on understanding and optimizing electrolyte decomposition mechanisms.The review also highlights the significance of modifying conductive agents and employing innovative separators to further enhance the stability of AZIBs.By integrating these cutting-edge approaches,this review anticipates substantial advancements in the stability of high-voltage cathode materials,paving the way for the broader application and development of AZIBs in energy storage.
基金Project(214M438)supported by the Scientific and Technological Research Council of Turkey(TUBITAK)Projects(20795,42796)supported partially by Scientific Research Projects Coordination Unit of Istanbul University,Turkey
文摘Highly porous Mg-Ca-Zn-Co alloy scaffolds for tissue engineering applications were produced by powder metallurgy based space holder-water leaching method.Mg-Ca-Zn-Co alloy foam can be used as a scaffold material in tissue engineering.Carbamide was used as a space holder material.Fluoride conversion coating was synthesized on the alloy by immersion treatment in hydrofluoric acid(HF).Increasing Zn content of the alloy increased the elastic modulus.Ca addition prevented the oxidation of the specimens during sintering.Electrochemical corrosion behaviour of the specimens was examined in simulated body fluid.Corrosion rate decreased with Zn addition from1.0%up to3.0%(mass fraction)and then increased.Mass loss of the specimens initially decreased with Zn addition up to about3%and then increased.Fluoride conversion coating increased the corrosion resistance of the specimens.
文摘An Al2O3-TiB2 nanocomposite was successfully synthesized by ball milling of Al, TiO2 and two B source materials of B2O3 （system （1）） and H3BO3 （system （2））. Phase identification of the milled samples was examined by Xray diffraction. The morphology and microstructure of the milled powders were monitored by scanning electron microscopy and transmission electron microscopy. It was found that the formation of this composite was completed after 15 and 30 h of milling time in systems （1） and （2）, respectively. More milling energy was required for the formation of this composite in system （2） due to the lubricant properties of HaBO3 and also its decomposition to HBO2 and B2O3 during milling. On the basis of X-ray diffraction patterns and thermodynamic calculations, this composite was formed by highly exothermic mechanically induced self-sustaining reactions （MSR） in both systems. The MSR mode took place around 9 h and 25 h of milling in systems （1） and （2）, respectively. At the end of milling （15 h for system （1） and 30 h for system （2）） the grain size of about 35-50 nm was obtained in both systems.
文摘Powder metallurgical Cu-Ti alloys with different titanium additions produced by hot pressing were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and hardness, wear and bending tests. The addition of titanium to copper caused the formation of different intermetallic layers around titanium particles. The titanium content of the intermetallics decreased from the center of the particle to the copper matrix. The hardness, wear resistance, and bending strength of the materials increased with increasing Ti content, whereas strain in the bending test decreased. Worn surface analyses showed that different wear mechanisms were active during the wear test of specimens with different chemical compositions. Changes in the properties of the materials with titanium addition were explained by the high hardness of different Cu-Ti intermetallic phases.
文摘Joining of dissimilar aluminium-copper is an emerging area of interest for both research and industry due to its complex nature.Friction stir welding was attempted to evaluate the joint strength without offset at the butt line between AA6063 to HCP copper sheet under different combination of rotational speed of 800 and 1000 r/min and travel speed of 20 and 40 mm/min.Material flow was studied in detail for different combinations of parameters with optical microscopy and elemental mapping by energy dispersive X-ray spectroscopy（EDS）.The results were correlated with the microstructural characteristics and formation of intermetallics at the bond interface using microhardness test and X-ray diffraction（XRD） technique.Material flow clearly suggests that energy input at 800 r/min and 20 mm/min is sufficient to plasticize both the materials with formation of higher amount of thermodynamically stable and hard intermetallic phases Al4Cu9 and Al Cu4（slower cooling rate of 88 K/s） than that at 800 r/min and 40 mm/min（faster cooling rate of 154 K/s）,attributed maximum joint strength（~78.6% of aluminium base metal）.
基金the 100 Talented Team of Hunan Province(XiangZu[2016]91)the“Huxiang high-level talents”program(no.2018RS3077,no.2019RS1007).
文摘Traditional synthetic methodologies are confronted with great challenges to fabricate complex nanomaterials with delicate design,high efficiency and excellent sustainability.During the past decade,bio-inspired synthesis has been extensively applied as an effective and efficient strategy for the fabrication of nanomaterials and nanostructures.Mimicking electrode materials at nanoscale in the aspect of either structure or functionality has been receiving surging interest because of their incomparable advantages and outperforming properties.In this review,we summarize the recent progresses on bio-inspired synthesis of nanomaterials and smart structures in the field of energy storage and conversion.Firstly,an overall introduction of bio-inspired synthetic strategies will be presented,with focus on the biotemplates and bio-resources.Following that,a library of complex mimicking structures featured by high-order,hierarchical porosity,or bionic function are introduced,with discussion on their chemical and physical properties associated with the structure.The enhanced electrochemical properties such as energy density,cycling stability,etc.in different electrochemical systems will be also discussed.At last,we will expand the perspectives regarding the advantages and limitations of bioinspired strategy and possible solutions in the future.
文摘In this study, resistance spot weldability of 180 grade bake hardening steel （BH180）, 7123 grade interstitial free steel （IF7123） and 304 grade austenitic stainless steel （AISI304L） with each other was investigated. In the joining process, electrode pressure and weld current were kept constant and six different weld time were chosen. Microstructure, microhardness, tensile-shear properties and fracture types of resistance spot welded joints were examined. In order to characterize the metallurgical structure of the welded joint, the microstructural profile was developed, and the relationship between mechanical properties and microstructure was determined. The change of weld time, nugget diameter, the HAZ （heat affected zone） width and the electrode immersion depth were also investigated. Welded joints were examined by SEM （scanning electron microscopy） images of fracture surface. As a result of the experiment, it was determined that with increasing weld time, tensile shear load bearing capacity （TLBC） increased with weld time up to 25 cycle and two types of tearing occurred. It was also determined that while the failure occurred from IF side at the BHIS0＋IF7123 joint, it occurred from the BH180 side at the BHIS0＋AISI304L joint.
文摘To study the formation of detrimental phases under the sulfur gas impurity to the long-term degradation in the cathode material,the classic cathode material,(La_(0.8)Sr_(0.2))_(0.95)MnO_(3)(LSM),was prepared,sintered,and annealed at 800,900,and 1000℃ in the sulfur-containing atmospheres,respectively.Through X-ray diffraction,scanning electron microscope,and transmission electron microscopy techniques,as well as the computer coupling of phase diagrams and thermochemistry methodology,the secondary phases,especially the detrimental ones,under different conditions were predicted and experimentally verified correspondingly.Furthermore,sulfur poisoning results indicate that the accelerated tests might have degradation mechanisms different from actual operation conditions.More importantly,comprehensive comparisons among various impurity-containing conditions were also made to recommend better operation parameters.
基金"TEQIP,COE Phase Ⅱ "in Jadavpur University for the support of this work
文摘One of the thrust areas of research is to find an alternative fuel to meet the increasing demand for energy.Glucose is a good source of alternative fuel for clean energy and is easily available in abundance from both naturally occurring plants and industrial processes.Electrochemical oxidation of glucose in fuel cell requires high electro-catalytic surface of the electrode to produce the clean electrical energy w ith minimum energy losses in the cell.Pt and Pt based alloys exhibit high electro-catalytic properties but they are expensive.For energy synthesis at economically cheap price,non Pt based inexpensive high electro catalytic material is required.Electro synthesized Zn O-Al2O3composite is found to exhibit high electro-catalytic properties for glucose oxidation.The Cyclic Voltammetry and Chronoamperometry curves reflect that the material is very much comparable to Pt as far as the maximum current and the steady state current delivered from the glucose oxidation are concerned.XRD image confirms the mixed oxide composite.SEM images morphology show increased 3D surface areas at higher magnification.This attributed high current delivered from electrochemical oxidation of glucose on this electrode surface.
文摘A promising friction material, Iron -based friction material, was prepared by powder metallurgy (PM) processing utilizing hot powder preform forging (near net-shape).The preparation of the product and its characterization are presented in this paper. These products are useful in heavy duty Military Aircraft applications such as AN-32. In order to eliminate costly environmental control systems to protect products during their high temperature processing (as is conventionally practiced employing hydrogen gas), the present investigation relies on carbon (mixed in the brake pad formulation) as reducing agent and high temperature oxidation resistant glassy coating (separately developed) applied over the product’s surface after cold compacting. After conducting an initial characterization such as hardness, density and Pin-on Disc tests, the samples were tested in sub-scale dynamometer under Rejected Take Off conditions. It was observed that the obtained density in the present investigation is higher than the reported density obtained by sintering route, and wear is on the lower side of the range as per the Aeronautical Standards. Optical metallography was used to investigate the microstructure of friction, interface and backing layer. It was observed that the distribution of ingredients in matrix was homogeneous. The results also indicate that the coefficient of friction is more stable, and wear is lower with respect to temperature rise. .
文摘Polymeric materials especially nanocomposites(Graphene,MXene based)are widely used in food,electronics,biomedical,batteries,energy storage,fuel cells,wastewater treatment,and automotive[1].Nanocomposites are stronger,lighter,and stiffer and can improve properties such as mechanical strength,electrical conductivity,thermal stability,flame retardancy,surface appearance,optical clarity and chemical resistance.Current research is focusing on nanocomposites applications[1-3],CO_(2)capturing polymers[4],making polymers degradable[5-7]especially developing bio-composites[8]and green composites[9,10]which are degradable。
文摘Graphene oxide (GO) reduced by Stachys lavandulifolia extract (SLE) was produced and characterised. The anti-corrosion behaviour of epoxy coatings containing GO and rGO nanosheets was investigated. FESEM-EDS, FT-IR, and Raman spectroscopy were used to examine the microstructure and chemical composition of the nanosheets and epoxy coatings. EIS experiment was used to explore the corrosion behaviour of the coatings. The O/C ratio for GO and rGO-SLE was found to be 2.5 and 4.5, indicating a decrease in the carbon content after the reduction of GO, confirming the adsorption of SLE onto the GO nanosheets. The successful reduction of GO in the presence of SLE particles was confirmed by disappearing the C=O peak and a significant decrease in the C-O-C bond intensity. The epoxy/rGO- SLE coatings exhibited the highest double-layer thickness and excellent corrosion resistance compared to neat epoxy and epoxy/GO coatings, emphasizing the significant role of rGO in enhancing the protective performance of epoxy coatings. The highest values for total charge transfer and film resistances and the inhibition efficiency were observed to be 6529 Ω·cm^(2) and 90%, respectively, for the epoxy/rGO-SLE coated steel plate. It was also found that the epoxy/0.15 wt.% rGO-SLE coating demonstrates the best corrosion resistance performance.
基金supported by the U.S.Army Research Laboratory through their award#W911NF-22-2-0040the Ministry of Education,Youth and Sports of the Czech Republic through the e-INFRA CZ(ID:90254).
文摘Designing high-performance high-entropy alloys(HEAs)with transformation-induced plasticity(TRIP)or twinning-induced plasticity(TWIP)effects requires precise control over stacking fault energy(SFE)and phase stability.However,the vast complexity of multicomponent systems poses a major challenge for identifying promising candidates through conventional experimental or computational methods.A high-throughput CALPHAD framework is developed to identify compositions with potential TWIP/TRIP behaviors in the Cr-Co-Ni and Cr-Co-Ni-Fe systems through systematic screening of stacking fault energy(SFE),FCC phase stability,and FCC-to-HCP transition temperatures(T0).The approach combines TC-Python automation with parallel Gibbs energy calculations across hundreds of thousands of compositions,enabling efficient extraction of metastable FCC-dominant alloys.The high-throughput results find 214 compositions with desired properties from 160,000 candidates.Detailed analysis of the Gibbs energy distributions,phase fraction trends,and temperature-dependent SFE evolution reveals critical insights into the thermodynamic landscape governing plasticity mechanisms in HEAs.The results show that only a narrow region of the compositional space satisfies all screening criteria,emphasizing the necessity of an integrated approach.The screened compositions and trends provide a foundation for targeted experimental validation.Furthermore,this work demonstrates a scalable,composition-resolved strategy for predicting deformation mechanisms in multicomponent alloys and offers a blueprint for integrating thermodynamic screening with mechanistic understanding in HEA design.
基金funded by the National Science and Technology Major Project for the Exploration and Development of New Types of Oil and Gas(No.2024ZD14066)the National Natural Science Foundation of China(No.52274053)+1 种基金the Natural Science Foundation of Beijing Municipality(No.3173044)the Xinjiang Conglomerate Reservoir Laboratory Development Foundation Project(No.2020D04045)。
文摘Carbon dioxide enhanced oil recovery(CO_(2)-EOR)technology is used for oil production and CO_(2) storage in reservoirs.Methods are being constantly developed to optimize oil recovery and CO_(2) storage during the CO_(2) displacement process,especially for low-permeability reservoirs under varying geological conditions.In this study,long-core experiments and trans-scale numerical simulations are employed to examine the characteristics of oil production and CO_(2) storage.Optimal production parameters for the target reservoir are also proposed.The results indicate that maintaining the pressure at 1.04 to 1.10 times the minimum miscible pressure(MMP)and increasing the injection rate can enhance oil production in the early stage of reservoir development.In contrast,reducing the injection rate at the later stages prevents CO_(2) channeling,thus improving oil recovery and CO_(2) storage efficiency.A solution-doubling factor is introduced to modify the calculation method for CO_(2) storage,increasing its accuracy to approximately 90%.Before CO_(2) breakthrough,prioritizing oil production is recommended to maximize the economic benefits of this process.In the middle stage of CO_(2) displacement,decreasing the injection rate optimizes the coordination between oil displacement and CO_(2) storage.Further,in the late stage,reduced pressure and injection rates are required as the focus shifts to CO_(2) storage.
基金Funded by Social Development Plan in Science and Technologyof Jiangsu Province (No.BS2006033)
文摘The pozzolanic activity of coal gangue burned at different burning temperatures was investigated. The burned coal gangue was mixed with portland cement in different proportions （ 20% - 60% ）. The pozzolanic activity of coal gangue burned and the hydration products were examined, the compressive strengths of the pastes of the mixtures were tested, and the mechanism of the reaction was discussed. The experimental results slum, that the coal gangue burned at 750 ℃ has the optimum pozzolanic activity, and the burned coal ganguc with SiO2 and Al2 O3 is in an active form. When the coal gangue burned at 750℃ is mixed into portland cement, the content of calcium hydroxide in paste is significantly reduced, while the contents of hydrated calcium silk.ate and hydrated calcium aluminate are increased accordingly, hence resulting in the improvement of the microstructure of mortar. The compressive strength of cement paste decreases with increasing the content of burncd coal gangue. The decease in strength is small in the range of 20% - 30% coal gangue substitution and significant in 30%- 60% substitution.
文摘Grade A （GA） and high strength steel DH36 ship steels possessing different chemical compositions were used, and strength properties of GA steel and DH36 steel were compared. Additionally, 4 types of dual phase （DP） steels with different martensite volume fractions （MVFs） were produced from GA steel by means of heat treatment and they were compared with other steels through conducting mierostructure, microhardness, tensile and impact tests. The fracture surfaces of specimens （DH36, GA and DP steels） exposed to tensile and Charpy impact tests were investigated by scanning electron microscope. Furthermore, it was found that the specimens quenched from 800 and 900℃ had better strength than DH36 steel. The tensile test results indicated that the tensile strength of DP steel water quenched from 900℃ was 3 times that of GA steel and twice that of DH36 steel.
文摘Zinc coated dual phase 600 steel （DP 600 grade） was investigated, utilisation of which has gradually increased with each passing day in the automotive industry. The adhesive bonding （AB）, resistance spot welding （RSW）, and adhesive weld bonding （AWB） ioints of the zinc coated DP 600 steel were investigated. Additionally, the zinc coating was removed using HCL acid in order to investigate the effect of the coating. The microstructure, tensile shear strengths, and fracture properties of adhesive bonding （AB）, resistance spot welding （RSW）, and adhesive weld bonding （AWB） joints of the coated and uncoated DP 600 steel were compared. In addition, a mechani cal-electrical-thermal coupled model in a finite element analysis environment was utilised. The thermal profile phe nomenon was calculated by simulating this process. The results of the tensile shear test indicated that the tensile load bearing capacity （TLBC） values of the coated specimens among the three welding methods were higher than those of the uncoated specimens. Additionally, the tensile strength of the AWB joints of the coated and uncoated specimens was higher than that of the AB and RSW joints. It was determined that the fracture behaviours and the deformation caused were different for the three welding methods.
文摘Friction stir welding （FSW） of 6061 aluminium alloy butt joint was carried out at each rotation speed of 600, 800, 1000, 1200 r/min for two different travel speeds, 80 and 100 mm/min, at a constant probe depth of 1.85 mm. The calculated energy input based on the FSW parameters studied shows that the ultimate tensile strength （UTS） of the butt joint is obtained within a certain range of energy input of 297 kJ to 354 kJ out of total range of energy input studied from 196 kJ to 405 kJ. The fatigue behaviors of high-strength and low-strength joints performed at different stress ratios, i.e., 0.5, 0.3, 0.1, -0.3, -0.5, indicate that the fatigue behaviors of both the welds are sensitive to the microstructural features, such as stir zone （SZ）, thermo mechanically affected zone （TMAZ） and heat affected zone （HAZ）. The observed fatigue strengths were discussed in terms of the microstructure, crack path behavior and fracture surface.
