Deformation kink is one of the important strengthening mechanisms of the long-period-stacking-ordered(LPSO)phase containing magnesium(Mg)alloys,while the deformation twin is generally suppressed.To optimize the mechan...Deformation kink is one of the important strengthening mechanisms of the long-period-stacking-ordered(LPSO)phase containing magnesium(Mg)alloys,while the deformation twin is generally suppressed.To optimize the mechanical properties of LPSO containing Mg alloy by simultaneously exciting kink and twin,we successfully prepared the Mg-Zn-Y-Zr alloy featuring intragranular LPSO phase and free grain boundary LPSO phase by homogenization.We unraveled the corresponding strengthening and toughening mechanisms through transmission electron microscopy characterization and theoretical analysis.The high strength and good plasticity of the homogenized alloy benefit from the synergistic deformation mechanism of multiple kinking and twining in the grains.And the activation of kinking and twinning depends on the thicknesses of LPSO lamellae and their relative spacing.These results may shed light on optimizing the design of Mg alloys regulating the microstructure of LPSO phases.展开更多
Energy-saving in China's iron and steel industry still relies on the development and improvement of short-term energy saving technologies.Therefore,a special converter smelting technology incorporating energy savi...Energy-saving in China's iron and steel industry still relies on the development and improvement of short-term energy saving technologies.Therefore,a special converter smelting technology incorporating energy saving was proposed.To evaluate the energy-saving potential of the CO_(2)–O_(2)mixed injection(COMI)technology,collected production data were used to develop an improved techno-economic model.Calculations reveal that the technology can save energy through auxiliary material consumption,sensible heat of solid by-product,iron loss reduction,and energy recovery.The application of COMI technology in an enterprise is cost effective,involving the energy saving potential of 0.206 GJ/t,the cost of conserved energy of−48.83 yuan/GJ,and a simple payback period of 0.35 year for a 60-million-yuan investment.Sensitivity analysis shows that the investment cost and discount rate primarily influence the cost of conserved energy of the technology.As the discount rate increased,the cost of conserved energy also gradually increased.Overall,the COMI technology is an energy-saving technology with good development prospects.展开更多
Dual-phase accelerated cooling(DPAC) was applied to X80 pipeline steel to obtain its microstructure with different amounts of bainite and ferrite. The microstructure, hardness, and polarization behaviors of the steel,...Dual-phase accelerated cooling(DPAC) was applied to X80 pipeline steel to obtain its microstructure with different amounts of bainite and ferrite. The microstructure, hardness, and polarization behaviors of the steel, cooled to different temperatures, were investigated. Results showed that, with decreasing cooling temperature, the amount of polygon ferrite(PF) increased while that of acicular ferrite(AF) decreased. The amount of bainite correspondingly decreased, except when cooled to 760°C. Moreover, the grain size of ferrite increased. The corrosion behaviors of different phases were distinct. Martensite/austenite(M/A) islands presented at the grain boundary of the PF phase caused small pits. Numerous micro-corrosion cells were formed in the AF and bainite phases, where micropores were prone to form. X80 pipeline steel cooled to 700°C had the best corrosion resistance in the simulated seawater. The decreased amount of the PF phase reduced the area of cathode, resulting in slight corrosion. About 40 vol% of the bainite phase provided strength while the PF phase provided adequate ductility to the X80 steel. It was concluded that the appropriate cooling temperature was 700°C for ideal corrosion resistance and mechanical properties.展开更多
Calcium sulphoaluminate(3CaO·3Al2O3·CaSO4,abbreviated as C4A3S)was synthesized by sintering at1375°C for2h with analytically pure carbonate calcium,alumina and dihydrate calcium sulfate.The crystal stru...Calcium sulphoaluminate(3CaO·3Al2O3·CaSO4,abbreviated as C4A3S)was synthesized by sintering at1375°C for2h with analytically pure carbonate calcium,alumina and dihydrate calcium sulfate.The crystal structure of C4A3S was characterized by XRD,SEM and TEM.Alumina leaching properties in Na2CO3solution were studied,and the leaching mechanism was investigated by means of Raman spectrum and XRD.The results show that C4A3S has porous morphology.The polycrystallines and single crystals coexist in C4A3S and grow along different directions.The alumina leaching rate of C4A3S is98.41%,which is higher than that of12CaO·7Al2O3under the optimal condition.The aluminum and sulfur elements exist in the leaching solution in the form of Al(OH)4and24SO,respectively,and the calcium exists as CaCO3in the leaching residues.展开更多
Heterogeneous interfaces produced by interdomain interactions on a nanoscale performs a crucial role in boosting the properties of an electrocatalyst toward oxygen evolution reaction(OER)process.Herein,a series of dua...Heterogeneous interfaces produced by interdomain interactions on a nanoscale performs a crucial role in boosting the properties of an electrocatalyst toward oxygen evolution reaction(OER)process.Herein,a series of dual-phase electrodes with intimately connected heterointerfaces are prepared by in situ decomposing solid solution oxide of Ni_(x)Co_(y)Fe_(100-x-y)O,which grew on Ni foam massively via an ultrafast combustion approach.Particularly,with high-reaction kinetics caused by the reduction treatment at 450℃,the less electronegative Fe and Co are more oxyphilic than Ni,which facilitated their co-exsolution and formation of CoFe_2O_4/NiO oxide with enriched oxygen vacancies.Benefiting from the nanoporous framework,heterojunction structure,and oxygen defects,the self-supporting electrodes present rapid charge/mass transmission and provide abundant active sites for OER.The optimized sample(R-SNCF4.5)shows low overpotentials of 226 and 324 mV at 10 and100 mA·cm^(-2),a small Tafel slope(46.7 mV·dec^(-1)),and excellent stability.The assembled R-SNCF4.5//Pt/C/NF electrolyzer demonstrates continuous electrolysis over 50 h at a current density of 10 mA·cm^(-2),under 1.51 V.Density functional theory(DFT)calculations verify that the strong electronic modulation plays a critical part in the CoFe_2O_4/NiO hybrid by lowering the energy barriers for the ratedetermining steps,and Fe sites are the most active OER sites.展开更多
Three-dimentional(3D)transition metal selenides with sufficient channels could produce significant superiority on enhancing reaction kinetics for sodium-ion batteries.However,the thorough exploration of 3D architectur...Three-dimentional(3D)transition metal selenides with sufficient channels could produce significant superiority on enhancing reaction kinetics for sodium-ion batteries.However,the thorough exploration of 3D architecture with a facile strategy is still challenging.Here we report that a polycrystalline Cu_(2-x)Se film was epitaxial grown on(220)facets-exposed Cu by direct selenization of a nanoporous Cu skeleton,which is obtained by dealloying rolled Cu Mn@Cu alloy foil.Density functional theory calculation result shows strong adsorption energy for Se atoms on Cu(220)planes during selenization reaction,rendering a low energy consumption.By virtue of this core-shell 3D nanoporous architecture to offer abundant active sites and endow fast electron/ion transportation,the nanoporous Cu_(2-x)Se@Cu-0.15 composite electrode exhibits remarkable sodium-ion storage properties with high reversible capacity of 950.6μAh/cm^(2)at 50μA/cm^(2),suprior rate capability of 457.6μAh/cm^(2)at 500μA/cm^(2),as well as an ultra-long stability at a high current density.Mechanism investigation reveals that the electrochemical reaction is a typical conversion-type reaction with different intermediates.This novel electrode synthetic strategy provides useful instructions to design the high-performance anode material for sodium-ion batteries.展开更多
The Ti-20Zr-6.5Al-4V(T20Z,wt%)alloy surface was treated by the process of laser surface nitriding.The evolution of microstructures and microhardness has been investigated by changing the laser power parameter from 120...The Ti-20Zr-6.5Al-4V(T20Z,wt%)alloy surface was treated by the process of laser surface nitriding.The evolution of microstructures and microhardness has been investigated by changing the laser power parameter from 120 to 240 W.All laser-treated T20Z samples show two regions with distinctly different microstructural features,as compared with the untreated substrate:dense TiN dendrites and(α+β)-Ti(remelting zone,RMZ),nanoscaleαlaths doped with part of p phase(heat-affected zone,HAZ).The formation of TiN dendrites can be analyzed by a series of complex reactions during the process of melting and solidification.The increase in laser power results in the increase in content of TiN dendrite which is mainly due to the increase in energy input.In HAZ,the self-quenching effect leads to the formation of nanoscale a laths and the residue ofβphase.Microhardness profile of different regions was measured from the surface to the interior,and the highest microhardness was obtained(~HV 916.8)in the RMZ,as the laser power was set to 240 W.In the present study,we explained various microstructural characteristics induced by laser surface nitriding treatment.展开更多
Titanium alloys possess excellent corrosion resistance in marine environments,thus the possibility of their corrosion caused by marine microorganisms is neglected.In this work,microbiologically influenced corrosion(MI...Titanium alloys possess excellent corrosion resistance in marine environments,thus the possibility of their corrosion caused by marine microorganisms is neglected.In this work,microbiologically influenced corrosion(MIC)of TC4 titanium alloy caused by marine Pseudomonas aeruginosa was investigated through electrochemical and surface characterizations during a 14-day immersion test.Results revealed that the unstable surface caused by P.aeruginosa resulted in exposure of Ti_(2)O_(3) and severe pitting corrosion with maximum pit depth of 5.7μm after 14 days of incubation.Phenazine-1-carboxylate(PCN),secreted by P.aeruginosa,promoted extracellular electron transfer(EET)and accelerated corrosion.Deletion of the phzH gene,which codes for the enzyme that catalyzes PCN production,from the P.aeruginosa genome,resulted in significantly decreased rates of corrosion.These results demonstrate that TC4 titanium alloy is not immune to marine MIC,and EET contributes to the corrosion of TC4 titanium alloy caused by P.aeruginosa.展开更多
Graphite anode materials are widely used in commercial lithium-ion batteries;however, the long electron/ion transportation path restricted its high energy storage. In this experiment, we designed a copper/graphite com...Graphite anode materials are widely used in commercial lithium-ion batteries;however, the long electron/ion transportation path restricted its high energy storage. In this experiment, we designed a copper/graphite composite with a dual three-dimensional(3 D) continuous porous structure combining used nonsolvent-induced phase separation and heat treatment, in which a large amount of graphite is embedded in the 3 D porous copper/carbon architecture. In the novel structure, not only the electron and Li^(+) transmission performances are improved, but also the space of current collector is fully utilized. Meanwhile,carbonized polyacrylonitrile network stabilizes the interface between graphite and copper matrix. The obtained copper/graphite composite anode has an initial discharge capacity of 524.6 mAh·g^(-1), a holding capacity of350 mAh·g^(-1) and excellent cycle stability(299.3 mAh·g^(-1) after 180 cycles at 0.1 C rate), exhibiting good electrochemical performance. The experimental results show that the mass loading of the copper/graphite composite electrode material is about 4.39 mg·cm^(-2). We also envisage replacing graphite with other high-capacity active materials to fill the current collector, which can provide a reference for the future development of next-generation advanced electrodes.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant No.52101015,52171021,and 51871222)Natural Science Foundation of Hebei Province(Grant No.E2020208083)Science and Technology Research Project of Colleges and Universities in Hebei Province(Grant No.BJK2022020).
文摘Deformation kink is one of the important strengthening mechanisms of the long-period-stacking-ordered(LPSO)phase containing magnesium(Mg)alloys,while the deformation twin is generally suppressed.To optimize the mechanical properties of LPSO containing Mg alloy by simultaneously exciting kink and twin,we successfully prepared the Mg-Zn-Y-Zr alloy featuring intragranular LPSO phase and free grain boundary LPSO phase by homogenization.We unraveled the corresponding strengthening and toughening mechanisms through transmission electron microscopy characterization and theoretical analysis.The high strength and good plasticity of the homogenized alloy benefit from the synergistic deformation mechanism of multiple kinking and twining in the grains.And the activation of kinking and twinning depends on the thicknesses of LPSO lamellae and their relative spacing.These results may shed light on optimizing the design of Mg alloys regulating the microstructure of LPSO phases.
基金the National Natural Science Foundation of China(Nos.52204342 and 52201073)Natural Science Foundation of Hebei Province(No.E2022208019)+1 种基金Natural Science Foundation of Hebei Education Department(Nos.BJK2024194 and BJK2024024)Natural Science Foundation of Hebei Education Department(No.QN2021058)for financial support.
文摘Energy-saving in China's iron and steel industry still relies on the development and improvement of short-term energy saving technologies.Therefore,a special converter smelting technology incorporating energy saving was proposed.To evaluate the energy-saving potential of the CO_(2)–O_(2)mixed injection(COMI)technology,collected production data were used to develop an improved techno-economic model.Calculations reveal that the technology can save energy through auxiliary material consumption,sensible heat of solid by-product,iron loss reduction,and energy recovery.The application of COMI technology in an enterprise is cost effective,involving the energy saving potential of 0.206 GJ/t,the cost of conserved energy of−48.83 yuan/GJ,and a simple payback period of 0.35 year for a 60-million-yuan investment.Sensitivity analysis shows that the investment cost and discount rate primarily influence the cost of conserved energy of the technology.As the discount rate increased,the cost of conserved energy also gradually increased.Overall,the COMI technology is an energy-saving technology with good development prospects.
基金financially supported by the National Natural Science Foundation of China(Nos.51761030 and 51701064)the Inner Mongolia Natural Science Foundation(No.2019MS05081)
文摘Dual-phase accelerated cooling(DPAC) was applied to X80 pipeline steel to obtain its microstructure with different amounts of bainite and ferrite. The microstructure, hardness, and polarization behaviors of the steel, cooled to different temperatures, were investigated. Results showed that, with decreasing cooling temperature, the amount of polygon ferrite(PF) increased while that of acicular ferrite(AF) decreased. The amount of bainite correspondingly decreased, except when cooled to 760°C. Moreover, the grain size of ferrite increased. The corrosion behaviors of different phases were distinct. Martensite/austenite(M/A) islands presented at the grain boundary of the PF phase caused small pits. Numerous micro-corrosion cells were formed in the AF and bainite phases, where micropores were prone to form. X80 pipeline steel cooled to 700°C had the best corrosion resistance in the simulated seawater. The decreased amount of the PF phase reduced the area of cathode, resulting in slight corrosion. About 40 vol% of the bainite phase provided strength while the PF phase provided adequate ductility to the X80 steel. It was concluded that the appropriate cooling temperature was 700°C for ideal corrosion resistance and mechanical properties.
基金Project (E2016208107) supported by the Natural Science Foundation of Hebei Province,ChinaProjects (QN2015002,BJ2016023) supported by the Science and Technology Foundation of Higher Education Institution of Hebei Province,China
文摘Calcium sulphoaluminate(3CaO·3Al2O3·CaSO4,abbreviated as C4A3S)was synthesized by sintering at1375°C for2h with analytically pure carbonate calcium,alumina and dihydrate calcium sulfate.The crystal structure of C4A3S was characterized by XRD,SEM and TEM.Alumina leaching properties in Na2CO3solution were studied,and the leaching mechanism was investigated by means of Raman spectrum and XRD.The results show that C4A3S has porous morphology.The polycrystallines and single crystals coexist in C4A3S and grow along different directions.The alumina leaching rate of C4A3S is98.41%,which is higher than that of12CaO·7Al2O3under the optimal condition.The aluminum and sulfur elements exist in the leaching solution in the form of Al(OH)4and24SO,respectively,and the calcium exists as CaCO3in the leaching residues.
基金financially supported by the National Natural Science Foundation of China(No.52101251)the Natural Science Foundation of Hebei Province(Nos.E2020208069 and B2020208083)。
文摘Heterogeneous interfaces produced by interdomain interactions on a nanoscale performs a crucial role in boosting the properties of an electrocatalyst toward oxygen evolution reaction(OER)process.Herein,a series of dual-phase electrodes with intimately connected heterointerfaces are prepared by in situ decomposing solid solution oxide of Ni_(x)Co_(y)Fe_(100-x-y)O,which grew on Ni foam massively via an ultrafast combustion approach.Particularly,with high-reaction kinetics caused by the reduction treatment at 450℃,the less electronegative Fe and Co are more oxyphilic than Ni,which facilitated their co-exsolution and formation of CoFe_2O_4/NiO oxide with enriched oxygen vacancies.Benefiting from the nanoporous framework,heterojunction structure,and oxygen defects,the self-supporting electrodes present rapid charge/mass transmission and provide abundant active sites for OER.The optimized sample(R-SNCF4.5)shows low overpotentials of 226 and 324 mV at 10 and100 mA·cm^(-2),a small Tafel slope(46.7 mV·dec^(-1)),and excellent stability.The assembled R-SNCF4.5//Pt/C/NF electrolyzer demonstrates continuous electrolysis over 50 h at a current density of 10 mA·cm^(-2),under 1.51 V.Density functional theory(DFT)calculations verify that the strong electronic modulation plays a critical part in the CoFe_2O_4/NiO hybrid by lowering the energy barriers for the ratedetermining steps,and Fe sites are the most active OER sites.
基金financially supported by the National Natural Science Foundation of China(Nos.52271011,52102291,52101251)。
文摘Three-dimentional(3D)transition metal selenides with sufficient channels could produce significant superiority on enhancing reaction kinetics for sodium-ion batteries.However,the thorough exploration of 3D architecture with a facile strategy is still challenging.Here we report that a polycrystalline Cu_(2-x)Se film was epitaxial grown on(220)facets-exposed Cu by direct selenization of a nanoporous Cu skeleton,which is obtained by dealloying rolled Cu Mn@Cu alloy foil.Density functional theory calculation result shows strong adsorption energy for Se atoms on Cu(220)planes during selenization reaction,rendering a low energy consumption.By virtue of this core-shell 3D nanoporous architecture to offer abundant active sites and endow fast electron/ion transportation,the nanoporous Cu_(2-x)Se@Cu-0.15 composite electrode exhibits remarkable sodium-ion storage properties with high reversible capacity of 950.6μAh/cm^(2)at 50μA/cm^(2),suprior rate capability of 457.6μAh/cm^(2)at 500μA/cm^(2),as well as an ultra-long stability at a high current density.Mechanism investigation reveals that the electrochemical reaction is a typical conversion-type reaction with different intermediates.This novel electrode synthetic strategy provides useful instructions to design the high-performance anode material for sodium-ion batteries.
基金financially supported by the Youth Top Talents Research Project of Hebei Provincial Education Department China(No.BJ2018052)the Natural Science Foundation of Hebei Province of China(Nos.E2019208205 and E2018208126)+3 种基金the National Natural Science Foundation of China(No.51701064)the Science and Technology on Plasma Dynamics Laboratory Fund Project(No.614220206021806)the Key Research and Development Program of Hebei Province(No.19211016D)the Open Foundation of State Key Laboratory of Metastable Materials Science and Technology(Nos.201804 and 201812).
文摘The Ti-20Zr-6.5Al-4V(T20Z,wt%)alloy surface was treated by the process of laser surface nitriding.The evolution of microstructures and microhardness has been investigated by changing the laser power parameter from 120 to 240 W.All laser-treated T20Z samples show two regions with distinctly different microstructural features,as compared with the untreated substrate:dense TiN dendrites and(α+β)-Ti(remelting zone,RMZ),nanoscaleαlaths doped with part of p phase(heat-affected zone,HAZ).The formation of TiN dendrites can be analyzed by a series of complex reactions during the process of melting and solidification.The increase in laser power results in the increase in content of TiN dendrite which is mainly due to the increase in energy input.In HAZ,the self-quenching effect leads to the formation of nanoscale a laths and the residue ofβphase.Microhardness profile of different regions was measured from the surface to the interior,and the highest microhardness was obtained(~HV 916.8)in the RMZ,as the laser power was set to 240 W.In the present study,we explained various microstructural characteristics induced by laser surface nitriding treatment.
基金This work was supported by the National Natural Science Foundation of China(U2006219,U1660118 and 51871050)the Fundamental Research Funds for the Central Universities of the Ministry of Education of China(N180205021,N180203019)Liaoning Revitalization Talents Program(No.XLYC1907158)。
文摘Titanium alloys possess excellent corrosion resistance in marine environments,thus the possibility of their corrosion caused by marine microorganisms is neglected.In this work,microbiologically influenced corrosion(MIC)of TC4 titanium alloy caused by marine Pseudomonas aeruginosa was investigated through electrochemical and surface characterizations during a 14-day immersion test.Results revealed that the unstable surface caused by P.aeruginosa resulted in exposure of Ti_(2)O_(3) and severe pitting corrosion with maximum pit depth of 5.7μm after 14 days of incubation.Phenazine-1-carboxylate(PCN),secreted by P.aeruginosa,promoted extracellular electron transfer(EET)and accelerated corrosion.Deletion of the phzH gene,which codes for the enzyme that catalyzes PCN production,from the P.aeruginosa genome,resulted in significantly decreased rates of corrosion.These results demonstrate that TC4 titanium alloy is not immune to marine MIC,and EET contributes to the corrosion of TC4 titanium alloy caused by P.aeruginosa.
基金financially supported by Tianjin Municipal Education Committee Scientific Research Project (No.2017KJ075)。
文摘Graphite anode materials are widely used in commercial lithium-ion batteries;however, the long electron/ion transportation path restricted its high energy storage. In this experiment, we designed a copper/graphite composite with a dual three-dimensional(3 D) continuous porous structure combining used nonsolvent-induced phase separation and heat treatment, in which a large amount of graphite is embedded in the 3 D porous copper/carbon architecture. In the novel structure, not only the electron and Li^(+) transmission performances are improved, but also the space of current collector is fully utilized. Meanwhile,carbonized polyacrylonitrile network stabilizes the interface between graphite and copper matrix. The obtained copper/graphite composite anode has an initial discharge capacity of 524.6 mAh·g^(-1), a holding capacity of350 mAh·g^(-1) and excellent cycle stability(299.3 mAh·g^(-1) after 180 cycles at 0.1 C rate), exhibiting good electrochemical performance. The experimental results show that the mass loading of the copper/graphite composite electrode material is about 4.39 mg·cm^(-2). We also envisage replacing graphite with other high-capacity active materials to fill the current collector, which can provide a reference for the future development of next-generation advanced electrodes.
