A pyrimidine derivative,6-phenyl-2-thiouracil(PT),was synthesized for developing a corrosion inhibitor(CI)applied in the protection of the nickel−aluminum bronze(NAB)in seawater.The anti-corrosion effect of PT was eva...A pyrimidine derivative,6-phenyl-2-thiouracil(PT),was synthesized for developing a corrosion inhibitor(CI)applied in the protection of the nickel−aluminum bronze(NAB)in seawater.The anti-corrosion effect of PT was evaluated by the mass loss experiment,electrochemical tests and surface analysis.The results show that PT exhibits excellent inhibition performance and the maximum inhibition efficiency of PT reaches 99.6%.The interaction mechanism was investigated through X-ray photoelectron spectroscopy(XPS)and molecule dynamics simulation based on the density functional theory(DFT).The S-Cu,Al-N and Cu-N bonds are formed by the chemical interactions,leading to the adsorption of PT on the NAB surface.The diffusion of corrosive species is hindered considerably by the protective PT film with composition of(PT-Cu)_(ads)and(PT-Al)_(ads)on the PT/NAB interface.The degree of suppression is increased with the addition of more PT molecules.展开更多
The layer-by-layer deposition strategy of additive manufacturing makes it ideal to fabricate dissimilar alloy components with varying functionality,which has promising application potential in a large number of indust...The layer-by-layer deposition strategy of additive manufacturing makes it ideal to fabricate dissimilar alloy components with varying functionality,which has promising application potential in a large number of industrial areas.In this study,two components composed of ERCuAl-A2 aluminum bronze(CuAl9)and Inconel 718 nickel-based superalloy were fabricated with different deposition orders by wire-arc directed energy deposition.Subject to changes in heat input and thermophysical properties of the substrate,the transition region of the deposited Cu-Ni component with the bottom half of CuAl9 and the top half of Inconel 718 is narrow and serrated.This region features a laminated intermetallic compound layer due to the convection and rapid cooling in the molten pool.In contrast,the Ni-Cu component deposited in the opposite order exhibits a 2 mm gradient transition zone.Within this region,a large number of diverse precipitates were found as well as regional variations in grain size due to the multi-layer partial remelting.Both two components show strong bonds and their tensile specimens tested along the vertical direction always fracture at the softer CuAl9 side.Excellent tensile properties along the horizontal direction were obtained for Cu-Ni(Ultimate tensile strength:573 MPa,yield stress:302 MPa,elongation:22%),while those of Ni-Cu are much lower due to the existence of the solidification cracks in the transition zone.The results from this study provide a reference for the additive manufacturing of Cu/Ni dissimilar alloy components,as well as their microstructure and mechanical properties control.展开更多
The effect of Cr addition on nickel aluminium bronze(NAB)alloy microstructure,mechanical properties,and erosion-corrosion behaviour has been studied.The results show that Cr addition does not change the composition of...The effect of Cr addition on nickel aluminium bronze(NAB)alloy microstructure,mechanical properties,and erosion-corrosion behaviour has been studied.The results show that Cr addition does not change the composition of the precipitated phases,more Cr entered theκphase and a small amount of Cr solubilized in the matrix,which increase the hardness of theκand matrix and decrease the potential difference between theκand matrix.NAB alloy with Cr shows high erosion-corrosion resistance at high flow rate conditions,due to its lower phase potential difference and higher surface hardness.At the flow rate of 3 m·s^(-1),the corrosion rate is 0.076 mm·year^(-1),which is~20%lower than that of the unadded Cr sample.Moreover,the corrosion product film contains Cr_(2)O_(3)and Cr^(3+),which improves the densification of the film and raises alloy’s corrosion resistance with Cr addition.The combination of mechanical and corrosion resistant properties may qualify this alloy as a potential candidate material for sustainable and safe equipment.展开更多
A novel aluminum bronze over the Cu-Al binary alloy eutectoid Cu-14Al-4.5Fe was prepared by a jointly-charging one-melting technique and conventional sand casting. The bronze coatings were atmospherically plasma spray...A novel aluminum bronze over the Cu-Al binary alloy eutectoid Cu-14Al-4.5Fe was prepared by a jointly-charging one-melting technique and conventional sand casting. The bronze coatings were atmospherically plasma sprayed on the 45# medium carbon steel substrate. The effect of rare earth Ce on the microstructures and Vickers hardness of the cast alloy and coatings were characterized by scanning electron microscopy, X-ray diffraction, electronic probe microanalysis, transmission electron microscopy and microhardness measurements. The results indicate that the hardness of both as-cast alloy and coating are enhanced by the addition of 0.6% Ce due to the refinement of κ phases which are well distributed in the matrix. The rapid solidification in the plasma spray processing retains Fe-supersaturated in the Al-bronze alloy coatings, which avoids the formation of eutectoid （α＋γ2） phase and stacking faults are found in the coatings with Ce added, accordingly improves the mechanical properties.展开更多
The atmospheric corrosion behavior of bronze under thin electrolyte layer （TEL） with different thicknesses was monitored using cathodic polarization curves, open circuit potential （OCP） and electrochemical impedan...The atmospheric corrosion behavior of bronze under thin electrolyte layer （TEL） with different thicknesses was monitored using cathodic polarization curves, open circuit potential （OCP） and electrochemical impedance spectroscopy （EIS）. Cathodic polarization result indicates that the cathodic limiting current density increases with decreasing the TEL thickness. EIS result shows that the corrosion rate increases with decreasing the TEL thickness at the initial stage because the corrosion is dominated by the cathodic process, whereas after long immersion time, the corrosion degree with the TEL thickness is in the sequence of 150 μm 〉 310 μm〉 10μm ≈ bulk solution 〉 57 μm. The measurements of OCP and EIS present in-situ electrochemical corrosion information and their results are in good agreement with that of physical characterizations.展开更多
The material of nickel aluminum bronze (NAB) presents superior properties such as high strength, excellent wear resistance and stress corrosion resistance and is extensively used for marine propellers. In order to est...The material of nickel aluminum bronze (NAB) presents superior properties such as high strength, excellent wear resistance and stress corrosion resistance and is extensively used for marine propellers. In order to establish the constitutive relation of NAB under high strain rate condition, a new methodology was proposed to accurately identify the constitutive parameters of Johnson?Cook model in machining, combining SHPB tests, predictive cutting force model and orthogonal cutting experiment. Firstly, SHPB tests were carried out to obtain the true stress?strain curves at various temperatures and strain rates. Then, an objective function of the predictive and experimental flow stresses was set up, which put the identified parameters of SHPB tests as the initial value, and utilized the PSO algorithm to identify the constitutive parameters of NAB in machining. Finally, the identified parameters were verified to be sufficiently accurate by comparing the values of cutting forces calculated from the predictive model and FEM simulation.展开更多
X-ray diffaction analysis(XRDA)data of the black or brown patina on the surfaces of eight kinds of bronze mirror samples show 4 or 5 broad diffuse peaks which corresponding to almost the same 20 angle, while their mat...X-ray diffaction analysis(XRDA)data of the black or brown patina on the surfaces of eight kinds of bronze mirror samples show 4 or 5 broad diffuse peaks which corresponding to almost the same 20 angle, while their matixes does not.These results indicate that those diffuse peaks were produced by the SnO2, microcrystals of 3 ￣5 nm size contained in the black or brown patina.The matrix of unearthed black patina bronze mirror numbered 223, gives strong XRDA diffraction peaks, indicating that there are a large amounts of non-oxidized bronze alloy particles surrounded by SnO2,which shows that the black patinas are not wholly metallic oxides (mainly SnO2),there are also a lot of original alloys of different sizes in grain in the patina.The bright-field image of the black patina sample gives the same result.展开更多
To investigate the effects of thickness and grain size on mechanical and deformation properties of C5210 phosphor bronze thin sheets, samples with different grain sizes were obtained through annealing heat treatment a...To investigate the effects of thickness and grain size on mechanical and deformation properties of C5210 phosphor bronze thin sheets, samples with different grain sizes were obtained through annealing heat treatment at different temperatures; and then tensile tests of samples with different thicknesses and grain sizes were conducted at room temperature. The results show that yield strength increases with decreasing thickness from 800 to 50 μm, but work hardening exponent and total elongation decrease, and a modified model was proposed to describe the relation between yield strength and thickness; yield strength decreases as the grain size increases, but work hardening exponent shows an increasing trend, total elongation increases to a peak and then decreases. Fracture morphology of tensile specimens was observed by SEM, which indicates that all tensile specimens are ductile fracture. The dimple intensity increases as the specimen thickness increases but reduces with the specimen grain size increasing.展开更多
With the development of society and the prosperity of Chinese literature,as a part of China’s soft power,Chinese chil dren literature is faced with the problem of international dissemination.The English version of Ca...With the development of society and the prosperity of Chinese literature,as a part of China’s soft power,Chinese chil dren literature is faced with the problem of international dissemination.The English version of Cao Wenxuan’s Bronze and Sunflow er won Hans Christian Andersen Award,the top award of children’s literature,which is a successful example of such dissemina tion.Therefore,the Chinese-English translation skills employed are worth studying.This paper aims to analyze the skills used to in the translation of short clauses,reiterative locution,simile,parallelism and dingzhen from the perspective of reception theory.It is found that by using such translation skills as omission,alliteration,repetition of prepositions and pronouns,and literal translation,the translator preserves and recreates the effect of the original text in ways that are more acceptable and idiomatic for the target reader.展开更多
The Scandinavian Bronze Age started quite rapidly at around 1750 BC, and is marked by three simultaneous events: 1) importation of bronze from the east Mediterranean region, 2) export of amber from southeast Sweden to...The Scandinavian Bronze Age started quite rapidly at around 1750 BC, and is marked by three simultaneous events: 1) importation of bronze from the east Mediterranean region, 2) export of amber from southeast Sweden to the east Mediterranean region, and 3) the carving of pictures of big ships on bedrock and boulders in southern Scandinavia. We take this as evidence of travel and trading by people coming from the east Mediterranean region on big ships via Gibraltar and the North Sea to Scandinavia. At the same time, the Sun cult flourished in southern Sweden and Denmark, as evidenced by monuments perfectly oriented with respect to the Sun’s daily and annual motions over the sky (e.g. Ales Stones), rock carvings of solar symbols and in solar alignment, and a number of ritual objects related to the Sun Cult (e.g. The Golden Sky Dome). In this paper, we summarize and update available data, especially the data from Southern Sweden.展开更多
The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness...The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness and pin-on-plate test showed that DLC coating had a greater hardness compared with NAB alloy.Besides,the decrease in friction coefficient from 0.2 for NAB substrate to 0.13 for the DLC-coated sample was observed.Potentiodynamic polarization and EIS results showed that the corrosion current density decreased from 2.5μA/cm2 for bare NAB alloy to 0.14μA/cm2 for DLC-coated sample in 3.5 wt.%NaCl solution.Moreover,the charge transfer resistance at the substrate−electrolyte interface increased from 3.3 kΩ·cm2 for NAB alloy to 120.8 kΩ·cm2 for DLC-coated alloy,which indicated an increase in corrosion resistance due to the DLC coating.展开更多
The corrosion behaviour of bronze alloy prepared by equal channel angular pressing(ECAP) was investigated in 3.5 wt. % Na Cl solution.Immersion corrosion tests and different electrochemical techniques were carried out...The corrosion behaviour of bronze alloy prepared by equal channel angular pressing(ECAP) was investigated in 3.5 wt. % Na Cl solution.Immersion corrosion tests and different electrochemical techniques were carried out. The results showed that ECAPed bronze samples exhibited higher corrosion resistance compared with the as-cast alloy and the passive current density decreased with increasing number of passes. Moreover,the morphology of alloys indicated that the corrosion damage on the surface of ECAPed bronze was smooth and uniform while the as-cast alloy suffered from selective corrosion.展开更多
Hydrogen molybdenum bronze (HxMoO3) can be electrodeposited on platinum and oxidized in two steps to the hydrogen molybdenum bronze with less amount of hydrogen HyMoO3 (y<x) and MoO3 when platinum electrode is cycl...Hydrogen molybdenum bronze (HxMoO3) can be electrodeposited on platinum and oxidized in two steps to the hydrogen molybdenum bronze with less amount of hydrogen HyMoO3 (y<x) and MoO3 when platinum electrode is cycled from -0.2 to 1.3V (vs. SCE) in 0.05 mol/L Na2MoO4 + 0.5 mol/L H2SO4 solution. During the formation of HxMoO3, the electrochemical reduction of molybdate existing in the form of polymolydate is reversible and is about a five-electron transfer reaction.展开更多
The deformation mechanism of C5191 phosphor bronze sheet under ultra-high-speed blanking was investigated.By virtue of a DOBBY-OMEGA F1 ultra-high-speed press,the ultra-high-speed blanking test was conducted on C5191 ...The deformation mechanism of C5191 phosphor bronze sheet under ultra-high-speed blanking was investigated.By virtue of a DOBBY-OMEGA F1 ultra-high-speed press,the ultra-high-speed blanking test was conducted on C5191 phosphor bronze sheets with a thickness of 0.12 mm at 3000 strokes per minute.The microstructures of the blanked edges were characterized and analyzed separately by electron back-scatter diffraction(EBSD)and transmission electron microscopy(TEM).The results show that grains in the blanked edges are stretched along the blanking direction.Strong{001}<100>cube textures(maximum pole densities of 9 and 12,respectively)and secondarily strong{011}<011>textures(maximum pole densities of 4 and 7,respectively)are formed in local zones.Additionally,deformation twins are found in the shear zone of the blanked edges which are rotated and coarsened due to the blanking-induced extrusion and local thermal effect which can further form into sub-grains with clear and high-angle boundaries.The C5191 phosphor bronze sheet is subjected to adiabatic shear during ultra-high-speed blanking,accompanied with dynamic recrystallization.展开更多
The effects of various amount of Y and La on the cast structure.the fluidity,the wearability and corrosion resistance of the high manganese aluminium bronze have been investigated.The results have shown that a proper ...The effects of various amount of Y and La on the cast structure.the fluidity,the wearability and corrosion resistance of the high manganese aluminium bronze have been investigated.The results have shown that a proper content of rare earth elements is able to refine the cast structure of the alloy,and furthermore to enhance its wearability and corrosion resistance.The reasons for these phenomena have also been discussed.展开更多
By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and t...By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and the bonding strength between the coating and the substrate were tested with a HV-1000 microhardness tester and a mechanical universal testing machine. The surface microstructure, cross-section and tensile fracture surface of the coating were observed with a scanning electron microscope(SEM). Correspondingly, the influences of the preheat treatment temperature of the bronze powder and the Al_2O_3 content on the coating performance were investigated. The results indicate that the hardness of bronze powders decreased and the coating deposition rate increased after the preheating treatment of the bronze powder. The Al_2O_3 content in the mixed powders contributed to the deformation of bronze powders during the spraying process. This trend resulted in varied performance of the coating.展开更多
The repair welding of UNS C95700manganese?aluminum bronze plates was done using different filler metals.Themicrostructure and mechanical properties of welds were studied.The main microstructural constituents wereα,β...The repair welding of UNS C95700manganese?aluminum bronze plates was done using different filler metals.Themicrostructure and mechanical properties of welds were studied.The main microstructural constituents wereα,βandκphases withdifferent morphologies.The addition of manganese decreased the percentage ofαphase in the microstructure of weldments from80%(Mn-free weld)to57%(12.5%Mn weld,mass fraction).The morphology ofκphase was lamellar in high nickel specimens andit was changed to a globular morphology for high manganese welds.Although the application of high manganese filler metal yieldedthe higher tensile and bending strengths of weldment compared with the weld using high nickel filler material,the optimummechanical properties of repair welds were obtained using a non-alloy filler material(ERCuAl-A2)for the underlay and highmanganese filler metal(ERCuMnNiAl)for filling passes.This weld presented an increase of39%in tensile strength compared withthe base metal,and no cracking was observed after bending test.展开更多
The microstructure,corrosion and cavitation erosion(CE)behaviors of the as-cast and four different heat treated nickel aluminum bronzes(NABs)in 3.5 wt.%NaCl solution were investigated.The results show that after annea...The microstructure,corrosion and cavitation erosion(CE)behaviors of the as-cast and four different heat treated nickel aluminum bronzes(NABs)in 3.5 wt.%NaCl solution were investigated.The results show that after annealing,β′transformed into the eutectoid microstructure,and moreκIV precipitated fromα.Less eutectoid microstructure and moreβ′were obtained after normalizing.The quenched NAB mainly consisted ofαandβ′phases,and fine,acicularαandκphases precipitated insideβ′after subsequent aging.The largest proportion of the eutectoid microstructure,which underwent severe selective phase corrosion,was responsible for the lowest corrosion resistance of the annealed NAB.The quenched NAB possessed the most protective film and hence the highest corrosion resistance.The mechanical attack was primarily responsible for the CE damage for the as-cast,annealed and normarlized NABs.The quenched and quenched+aged NABs exhibited superior CE resistance because of the high hardness.The CE−corrosion synergy dominantly caused CE degradation,and it was largely attributed to corrosion-enhanced-CE.展开更多
The element diffusion process of Nb_3Sn superconductors by bronze route was studied using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The critical current of superconductors was...The element diffusion process of Nb_3Sn superconductors by bronze route was studied using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The critical current of superconductors was measured by four-point method. The results show that a diffusion layer has formed around the boundaries between the filaments and bronze matrix after 15 h heat treatment. The diffusion layer thickness keeps stable after heat treatment duration of 50~75 h. The stable and solid Nb 3 Sn layer is obtained in the sample after 100 h heat treatment. Excessive heat treatment would induce superconductivity degeneration because of superconductor grain coarsening. The characteristics of the element diffusion process were discussed. The diffusion of tin atom is the governing factor in diffusion. In this study, Nb_3_Sn superconductors with good superconducting property were fabricated successfully at 670 °C after 100h heat treatment.展开更多
基金supported by the National Natural Science Foundation of China(No.52171069).
文摘A pyrimidine derivative,6-phenyl-2-thiouracil(PT),was synthesized for developing a corrosion inhibitor(CI)applied in the protection of the nickel−aluminum bronze(NAB)in seawater.The anti-corrosion effect of PT was evaluated by the mass loss experiment,electrochemical tests and surface analysis.The results show that PT exhibits excellent inhibition performance and the maximum inhibition efficiency of PT reaches 99.6%.The interaction mechanism was investigated through X-ray photoelectron spectroscopy(XPS)and molecule dynamics simulation based on the density functional theory(DFT).The S-Cu,Al-N and Cu-N bonds are formed by the chemical interactions,leading to the adsorption of PT on the NAB surface.The diffusion of corrosive species is hindered considerably by the protective PT film with composition of(PT-Cu)_(ads)and(PT-Al)_(ads)on the PT/NAB interface.The degree of suppression is increased with the addition of more PT molecules.
基金supported by the Key Research and Development Program of Shaanxi Province(2023-YBGY361)the National Natural Science Foundation of China(52275374 and 52205414)+1 种基金the Postdoctoral Fellowship Program of CPSF(GZC20232098)as well as the Xiaomi Foundation through Xiaomi Young Scholar Program。
文摘The layer-by-layer deposition strategy of additive manufacturing makes it ideal to fabricate dissimilar alloy components with varying functionality,which has promising application potential in a large number of industrial areas.In this study,two components composed of ERCuAl-A2 aluminum bronze(CuAl9)and Inconel 718 nickel-based superalloy were fabricated with different deposition orders by wire-arc directed energy deposition.Subject to changes in heat input and thermophysical properties of the substrate,the transition region of the deposited Cu-Ni component with the bottom half of CuAl9 and the top half of Inconel 718 is narrow and serrated.This region features a laminated intermetallic compound layer due to the convection and rapid cooling in the molten pool.In contrast,the Ni-Cu component deposited in the opposite order exhibits a 2 mm gradient transition zone.Within this region,a large number of diverse precipitates were found as well as regional variations in grain size due to the multi-layer partial remelting.Both two components show strong bonds and their tensile specimens tested along the vertical direction always fracture at the softer CuAl9 side.Excellent tensile properties along the horizontal direction were obtained for Cu-Ni(Ultimate tensile strength:573 MPa,yield stress:302 MPa,elongation:22%),while those of Ni-Cu are much lower due to the existence of the solidification cracks in the transition zone.The results from this study provide a reference for the additive manufacturing of Cu/Ni dissimilar alloy components,as well as their microstructure and mechanical properties control.
基金supported by Beijing Nova Program(No.20230484371)the National Key Research and Development Program of China(No.2021YFB3700700).
文摘The effect of Cr addition on nickel aluminium bronze(NAB)alloy microstructure,mechanical properties,and erosion-corrosion behaviour has been studied.The results show that Cr addition does not change the composition of the precipitated phases,more Cr entered theκphase and a small amount of Cr solubilized in the matrix,which increase the hardness of theκand matrix and decrease the potential difference between theκand matrix.NAB alloy with Cr shows high erosion-corrosion resistance at high flow rate conditions,due to its lower phase potential difference and higher surface hardness.At the flow rate of 3 m·s^(-1),the corrosion rate is 0.076 mm·year^(-1),which is~20%lower than that of the unadded Cr sample.Moreover,the corrosion product film contains Cr_(2)O_(3)and Cr^(3+),which improves the densification of the film and raises alloy’s corrosion resistance with Cr addition.The combination of mechanical and corrosion resistant properties may qualify this alloy as a potential candidate material for sustainable and safe equipment.
基金Projects (50804019, 51165021) supported by the National Natural Science Foundation of ChinaProject (0901ZTB009) supported by the Super Tutor Foundation from the Education Department of Gansu Province, China
文摘A novel aluminum bronze over the Cu-Al binary alloy eutectoid Cu-14Al-4.5Fe was prepared by a jointly-charging one-melting technique and conventional sand casting. The bronze coatings were atmospherically plasma sprayed on the 45# medium carbon steel substrate. The effect of rare earth Ce on the microstructures and Vickers hardness of the cast alloy and coatings were characterized by scanning electron microscopy, X-ray diffraction, electronic probe microanalysis, transmission electron microscopy and microhardness measurements. The results indicate that the hardness of both as-cast alloy and coating are enhanced by the addition of 0.6% Ce due to the refinement of κ phases which are well distributed in the matrix. The rapid solidification in the plasma spray processing retains Fe-supersaturated in the Al-bronze alloy coatings, which avoids the formation of eutectoid （α＋γ2） phase and stacking faults are found in the coatings with Ce added, accordingly improves the mechanical properties.
基金Projects (51131005, 51171172, 50801056) supported by the National Natural Science Foundation of ChinaProject (Y4110074) supported by Natural Science Foundation of Zhejiang Province, China
文摘The atmospheric corrosion behavior of bronze under thin electrolyte layer （TEL） with different thicknesses was monitored using cathodic polarization curves, open circuit potential （OCP） and electrochemical impedance spectroscopy （EIS）. Cathodic polarization result indicates that the cathodic limiting current density increases with decreasing the TEL thickness. EIS result shows that the corrosion rate increases with decreasing the TEL thickness at the initial stage because the corrosion is dominated by the cathodic process, whereas after long immersion time, the corrosion degree with the TEL thickness is in the sequence of 150 μm 〉 310 μm〉 10μm ≈ bulk solution 〉 57 μm. The measurements of OCP and EIS present in-situ electrochemical corrosion information and their results are in good agreement with that of physical characterizations.
基金Project(2014CB046704)supported by the National Basic Research Program of ChinaProject(2014BAB13B01)supported by the National Science and Technology Pillar Program of China
文摘The material of nickel aluminum bronze (NAB) presents superior properties such as high strength, excellent wear resistance and stress corrosion resistance and is extensively used for marine propellers. In order to establish the constitutive relation of NAB under high strain rate condition, a new methodology was proposed to accurately identify the constitutive parameters of Johnson?Cook model in machining, combining SHPB tests, predictive cutting force model and orthogonal cutting experiment. Firstly, SHPB tests were carried out to obtain the true stress?strain curves at various temperatures and strain rates. Then, an objective function of the predictive and experimental flow stresses was set up, which put the identified parameters of SHPB tests as the initial value, and utilized the PSO algorithm to identify the constitutive parameters of NAB in machining. Finally, the identified parameters were verified to be sufficiently accurate by comparing the values of cutting forces calculated from the predictive model and FEM simulation.
文摘X-ray diffaction analysis(XRDA)data of the black or brown patina on the surfaces of eight kinds of bronze mirror samples show 4 or 5 broad diffuse peaks which corresponding to almost the same 20 angle, while their matixes does not.These results indicate that those diffuse peaks were produced by the SnO2, microcrystals of 3 ￣5 nm size contained in the black or brown patina.The matrix of unearthed black patina bronze mirror numbered 223, gives strong XRDA diffraction peaks, indicating that there are a large amounts of non-oxidized bronze alloy particles surrounded by SnO2,which shows that the black patinas are not wholly metallic oxides (mainly SnO2),there are also a lot of original alloys of different sizes in grain in the patina.The bright-field image of the black patina sample gives the same result.
文摘To investigate the effects of thickness and grain size on mechanical and deformation properties of C5210 phosphor bronze thin sheets, samples with different grain sizes were obtained through annealing heat treatment at different temperatures; and then tensile tests of samples with different thicknesses and grain sizes were conducted at room temperature. The results show that yield strength increases with decreasing thickness from 800 to 50 μm, but work hardening exponent and total elongation decrease, and a modified model was proposed to describe the relation between yield strength and thickness; yield strength decreases as the grain size increases, but work hardening exponent shows an increasing trend, total elongation increases to a peak and then decreases. Fracture morphology of tensile specimens was observed by SEM, which indicates that all tensile specimens are ductile fracture. The dimple intensity increases as the specimen thickness increases but reduces with the specimen grain size increasing.
文摘With the development of society and the prosperity of Chinese literature,as a part of China’s soft power,Chinese chil dren literature is faced with the problem of international dissemination.The English version of Cao Wenxuan’s Bronze and Sunflow er won Hans Christian Andersen Award,the top award of children’s literature,which is a successful example of such dissemina tion.Therefore,the Chinese-English translation skills employed are worth studying.This paper aims to analyze the skills used to in the translation of short clauses,reiterative locution,simile,parallelism and dingzhen from the perspective of reception theory.It is found that by using such translation skills as omission,alliteration,repetition of prepositions and pronouns,and literal translation,the translator preserves and recreates the effect of the original text in ways that are more acceptable and idiomatic for the target reader.
文摘The Scandinavian Bronze Age started quite rapidly at around 1750 BC, and is marked by three simultaneous events: 1) importation of bronze from the east Mediterranean region, 2) export of amber from southeast Sweden to the east Mediterranean region, and 3) the carving of pictures of big ships on bedrock and boulders in southern Scandinavia. We take this as evidence of travel and trading by people coming from the east Mediterranean region on big ships via Gibraltar and the North Sea to Scandinavia. At the same time, the Sun cult flourished in southern Sweden and Denmark, as evidenced by monuments perfectly oriented with respect to the Sun’s daily and annual motions over the sky (e.g. Ales Stones), rock carvings of solar symbols and in solar alignment, and a number of ritual objects related to the Sun Cult (e.g. The Golden Sky Dome). In this paper, we summarize and update available data, especially the data from Southern Sweden.
文摘The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness and pin-on-plate test showed that DLC coating had a greater hardness compared with NAB alloy.Besides,the decrease in friction coefficient from 0.2 for NAB substrate to 0.13 for the DLC-coated sample was observed.Potentiodynamic polarization and EIS results showed that the corrosion current density decreased from 2.5μA/cm2 for bare NAB alloy to 0.14μA/cm2 for DLC-coated sample in 3.5 wt.%NaCl solution.Moreover,the charge transfer resistance at the substrate−electrolyte interface increased from 3.3 kΩ·cm2 for NAB alloy to 120.8 kΩ·cm2 for DLC-coated alloy,which indicated an increase in corrosion resistance due to the DLC coating.
文摘The corrosion behaviour of bronze alloy prepared by equal channel angular pressing(ECAP) was investigated in 3.5 wt. % Na Cl solution.Immersion corrosion tests and different electrochemical techniques were carried out. The results showed that ECAPed bronze samples exhibited higher corrosion resistance compared with the as-cast alloy and the passive current density decreased with increasing number of passes. Moreover,the morphology of alloys indicated that the corrosion damage on the surface of ECAPed bronze was smooth and uniform while the as-cast alloy suffered from selective corrosion.
文摘Hydrogen molybdenum bronze (HxMoO3) can be electrodeposited on platinum and oxidized in two steps to the hydrogen molybdenum bronze with less amount of hydrogen HyMoO3 (y<x) and MoO3 when platinum electrode is cycled from -0.2 to 1.3V (vs. SCE) in 0.05 mol/L Na2MoO4 + 0.5 mol/L H2SO4 solution. During the formation of HxMoO3, the electrochemical reduction of molybdate existing in the form of polymolydate is reversible and is about a five-electron transfer reaction.
基金The authors are grateful for the financial supports from Jiangsu Key Laboratory of Precision and Micro-manufacturing Technology of China(JSJMYWX2020-01)Zhejiang Provincial Natural Science Foundation of China(LY18E050005)the Startup Foundation for Introducing Talent of Nanjing Institute of Industry Technology(YK18-13-02)of China.
文摘The deformation mechanism of C5191 phosphor bronze sheet under ultra-high-speed blanking was investigated.By virtue of a DOBBY-OMEGA F1 ultra-high-speed press,the ultra-high-speed blanking test was conducted on C5191 phosphor bronze sheets with a thickness of 0.12 mm at 3000 strokes per minute.The microstructures of the blanked edges were characterized and analyzed separately by electron back-scatter diffraction(EBSD)and transmission electron microscopy(TEM).The results show that grains in the blanked edges are stretched along the blanking direction.Strong{001}<100>cube textures(maximum pole densities of 9 and 12,respectively)and secondarily strong{011}<011>textures(maximum pole densities of 4 and 7,respectively)are formed in local zones.Additionally,deformation twins are found in the shear zone of the blanked edges which are rotated and coarsened due to the blanking-induced extrusion and local thermal effect which can further form into sub-grains with clear and high-angle boundaries.The C5191 phosphor bronze sheet is subjected to adiabatic shear during ultra-high-speed blanking,accompanied with dynamic recrystallization.
文摘The effects of various amount of Y and La on the cast structure.the fluidity,the wearability and corrosion resistance of the high manganese aluminium bronze have been investigated.The results have shown that a proper content of rare earth elements is able to refine the cast structure of the alloy,and furthermore to enhance its wearability and corrosion resistance.The reasons for these phenomena have also been discussed.
基金financially supported by the National Key Research and Development Program of China(No.2016YFE0111400)the Program on Key Research Project of Gansu Province(No.17YF1WA159)the National High-end Foreign Experts Program of China(No.GTD20156200088)
文摘By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and the bonding strength between the coating and the substrate were tested with a HV-1000 microhardness tester and a mechanical universal testing machine. The surface microstructure, cross-section and tensile fracture surface of the coating were observed with a scanning electron microscope(SEM). Correspondingly, the influences of the preheat treatment temperature of the bronze powder and the Al_2O_3 content on the coating performance were investigated. The results indicate that the hardness of bronze powders decreased and the coating deposition rate increased after the preheating treatment of the bronze powder. The Al_2O_3 content in the mixed powders contributed to the deformation of bronze powders during the spraying process. This trend resulted in varied performance of the coating.
文摘The repair welding of UNS C95700manganese?aluminum bronze plates was done using different filler metals.Themicrostructure and mechanical properties of welds were studied.The main microstructural constituents wereα,βandκphases withdifferent morphologies.The addition of manganese decreased the percentage ofαphase in the microstructure of weldments from80%(Mn-free weld)to57%(12.5%Mn weld,mass fraction).The morphology ofκphase was lamellar in high nickel specimens andit was changed to a globular morphology for high manganese welds.Although the application of high manganese filler metal yieldedthe higher tensile and bending strengths of weldment compared with the weld using high nickel filler material,the optimummechanical properties of repair welds were obtained using a non-alloy filler material(ERCuAl-A2)for the underlay and highmanganese filler metal(ERCuMnNiAl)for filling passes.This weld presented an increase of39%in tensile strength compared withthe base metal,and no cracking was observed after bending test.
基金financially supported by the Fundamental Research Funds for the Central Universities of China (Nos. B210203049, B210204005)the Natural Science Foundation of Jiangsu Province, China (No. BK20191161)+1 种基金the Changzhou Sci & Tech Program, China (No. CJ20210154)the National Natural Science Foundation of China (Nos. 51601058, 51879089)
文摘The microstructure,corrosion and cavitation erosion(CE)behaviors of the as-cast and four different heat treated nickel aluminum bronzes(NABs)in 3.5 wt.%NaCl solution were investigated.The results show that after annealing,β′transformed into the eutectoid microstructure,and moreκIV precipitated fromα.Less eutectoid microstructure and moreβ′were obtained after normalizing.The quenched NAB mainly consisted ofαandβ′phases,and fine,acicularαandκphases precipitated insideβ′after subsequent aging.The largest proportion of the eutectoid microstructure,which underwent severe selective phase corrosion,was responsible for the lowest corrosion resistance of the annealed NAB.The quenched NAB possessed the most protective film and hence the highest corrosion resistance.The mechanical attack was primarily responsible for the CE damage for the as-cast,annealed and normarlized NABs.The quenched and quenched+aged NABs exhibited superior CE resistance because of the high hardness.The CE−corrosion synergy dominantly caused CE degradation,and it was largely attributed to corrosion-enhanced-CE.
基金supported by the National Natural Science Foundation of China(No.50925726)
文摘The element diffusion process of Nb_3Sn superconductors by bronze route was studied using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The critical current of superconductors was measured by four-point method. The results show that a diffusion layer has formed around the boundaries between the filaments and bronze matrix after 15 h heat treatment. The diffusion layer thickness keeps stable after heat treatment duration of 50~75 h. The stable and solid Nb 3 Sn layer is obtained in the sample after 100 h heat treatment. Excessive heat treatment would induce superconductivity degeneration because of superconductor grain coarsening. The characteristics of the element diffusion process were discussed. The diffusion of tin atom is the governing factor in diffusion. In this study, Nb_3_Sn superconductors with good superconducting property were fabricated successfully at 670 °C after 100h heat treatment.
