The precipitation characteristics and effect on strengthening mechanism of Cu-rich phases during short-time and long-time aging for Super 304H steels with different Cu content were investigated using X-ray diffraction...The precipitation characteristics and effect on strengthening mechanism of Cu-rich phases during short-time and long-time aging for Super 304H steels with different Cu content were investigated using X-ray diffraction （XRD）, scanning electron microscope （SEM） and transmission electron microscope （TEM）. The results show that the size of Cu-rich phase particles increases, the interspace of Cu-rich phase particles decreases and the density of Curich phases increases with the increase of Cu content during short-time aging （approximately 800 h） at 650℃ for Super 304H steels. During long-time aging （more than 2 000 h） at 650 ℃, Cu-rich phase precipitates sufficiently and the strengthening effect of Cu-rich phase is preferable in Super 304H steel containing Cu of 4%. The strengthening effect of Cu-rich phase in Super 304H steels containing Cu of 2.2% or 5% is weaker than that with Cu of 4% during long-time aging （more than 2 000 h）.展开更多
The effects of Cu content on the microstructure and mechanical properties of thixoformed Al-6Si-xCu-0.3Mg(x= 3,4,5and 6,mass fraction,%) alloys were studied.The samples were thixoformed at 50%liquid content and severa...The effects of Cu content on the microstructure and mechanical properties of thixoformed Al-6Si-xCu-0.3Mg(x= 3,4,5and 6,mass fraction,%) alloys were studied.The samples were thixoformed at 50%liquid content and several of the samples were treated with the T6 heat treatment.The samples were then examined by optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive X-ray(EDX) spectroscopy and X-ray diffraction(XRD) analysis,as well as hardness and tensile tests.The results show that the cooling slope casting and thixoforming process promote the formation of very fine and well distributed intermetallic compounds in the aluminium matrix and the mechanical properties of the alloys increase considerably compared with the permanent mould casting.The results also reveal that as the Cu content in the alloy increases,the hardness and tensile strength of the thixoformed alloys also increase.The ultimate tensile strength,yield strength and elongation to fracture of the thixoformed heat-treated Al-6Si-3Cu-0.3Mg alloy are 298 MPa,201 MPa and 4.5%,respectively,whereas the values of the thixoformed heat-treated alloy with high Cu content(6%) are 361 MPa,274 MPa and 1.1%,respectively.The fracture of the thixoformed Al-6Si-3Cu-0.3Mg alloy shows a dimple rupture,whereas in the alloy that contains the highest Cu content(6%),a cleavage fracture is observed.展开更多
A systematic study on how Cu content affects the microstructure and mechanical properties of rheo-diecasting Al-6Zn-2Mg-xCu alloys during solution treatment and ageing heat treatment was conducted.The swirled enthalpy...A systematic study on how Cu content affects the microstructure and mechanical properties of rheo-diecasting Al-6Zn-2Mg-xCu alloys during solution treatment and ageing heat treatment was conducted.The swirled enthalpy equilibrium device(SEED)was adopted to prepare the semi-solid slurry of Al-6Zn-2Mg-xCu alloys.The microstructure development and mechanical properties were studied using optical microscopy(OM),scanning electron microscopy(SEM),X-ray diffraction(XRD),differential scanning calorimetry(DSC),as well as hardness and tensile testing.The grain boundary and shape factor were calculated using image processing software(Image-Pro Plus 6.0).Results show that the alloys are composed of typical globular primaryα-Al grains,eutectic phases,and smaller secondaryα-Al grains.After solution and ageing heat treatment,the eutectic phases are dissolved into Al matrix when the Cu content is lower than 1.5wt.%,while some eutectic phases transform into Al_(2)CuMg(S)phases and remain at grain boundaries when Cu content reaches 2wt.%.T6 heat treatment significantly enhances the mechanical properties of rheo-diecasting Al-6Zn-2Mg-xCu alloys.When Cu concentration is 0.5wt.%-1.5wt.%,the ultimate tensile strength,yield strength and elongation of T6 treated alloys rise to around 500 MPa,420 MPa,and 18%,respectively.展开更多
In order to reduce implant-related infections and improve early osseointegration,we performed HF+anodic oxidation on the surface of the new antibacterial Ti-Cu alloy to make the titanium-based implants have a micro/su...In order to reduce implant-related infections and improve early osseointegration,we performed HF+anodic oxidation on the surface of the new antibacterial Ti-Cu alloy to make the titanium-based implants have a micro/submicron structure.On this basis,a series of surface-modified Ti-x Cu alloys with different Cu contents(3,5 and 7 wt%)were fabricated and a comprehensive study was conducted on MC3 T3-E1 cell adhesion,proliferation,apoptosis and its antibacterial activity against Staphylococcus aureus.Results showed that the Ti-x Cu alloys by HF etching+anodized possessed multifunctional characteristics of antibiofilm and antibacterial abilities,excellent biocompatibility and osteogenesis promoting abilities.Increment of Cu content significantly contributed to the antibacterial and osteogenic properties of HF etching+anodized Ti-Cu alloys.Cell proliferation rates of HF etching+anodized Ti-7 Cu alloys were lower than those of Ti-3 Cu and Ti-5 Cu alloys,while the early cell apoptosis rates were higher than Ti-3 Cu and Ti-5 Cu groups.All the above results finally presented that the HF etching+anodized Ti-5 Cu alloy exhibited extremely strong antibacterial properties,good biological compatibility and osteogenic ability,as well as the most excellent ductility and corrosion resistance,providing a great potential application for the future dental implantation.展开更多
In order to understand the heavy metal contamination of Cu in the farmland soil in the suburbs of Changchun City,and reveal the distribution of Cu content of soil in different farmland types,we use the methods field s...In order to understand the heavy metal contamination of Cu in the farmland soil in the suburbs of Changchun City,and reveal the distribution of Cu content of soil in different farmland types,we use the methods field survey and laboratory analysis,to analyze the Cu content of soil in different farmland types in the suburbs of Changchun City. Using SPSS statistical analysis software and ORING mapping software,we process the data of Cu content in 60 sampling points and draw the normal distribution map,and then analyze the distribution of Cu content of soil in different land use types. The results show that the Cu content of the farmland soil in the suburbs of Changchun City is between 41. 71 mg /kg and 116. 77 mg /kg,with an average of 53. 35 mg /kg,and the content in all sampling points is higher than the background value; in terms of the Cu content of soil,different land use types are sequenced in descending order(vegetable field > paddy > dry land).展开更多
The AgCu alloy is widely used in numerous industries such as electronics and electrical engineering due to its excellent electrical conductivity,thermal conductivity,and workability.However,the friction problems durin...The AgCu alloy is widely used in numerous industries such as electronics and electrical engineering due to its excellent electrical conductivity,thermal conductivity,and workability.However,the friction problems during its service can seriously affect the operational stability and service life.Therefore,it is of great significance to deeply explore the friction and wear behavior of the AgCu alloy.In this study,the molecular dynamics simulation method was employed to conduct an in-depth investigation of the friction and wear behavior of AgCu alloy with different friction depths,velocities,and Cu contents.It found that as the depth increases,the contact area enlarges,and the atomic packing,phase transformation,and dislocations increase,resulting in a roughly linear increase in the average and normal friction force.The characteristic of this wear mechanism is that it will create grooves on the surface and cause material transfer.At friction speeds of 0.5Å/ps,1Å/ps,and 1.5Å/ps,the average friction force increases with the increase of speed,accompanied by expanded strain localization and reduced twinning with intensified temperature under dynamic loading.The content of the Cu has a significant impact on the friction behavior.When the content increases,the softening of the alloy leads to a linear decrease in the average friction force.At the same time,the plasticity is enhanced,the strain region expands,and the disordered atomic structures increase.The results of this study provide an important theoretical basis for a deep understanding of the friction and wear mechanism of the AgCu alloy and the optimization of its performance.展开更多
By means of scanning electron microscopy(SEM), energy dispersive spectrum(EDS), X-ray diffractometry(XRD) and metallographic analysis, the effects of variation of magnesium content on phase constituents of Al-Mg-Si-Cu...By means of scanning electron microscopy(SEM), energy dispersive spectrum(EDS), X-ray diffractometry(XRD) and metallographic analysis, the effects of variation of magnesium content on phase constituents of Al-Mg-Si-Cu alloys were investigated. The results indicate that the constituents formed during casting alloys are main Al1.9CuMg4.1Si3.3,Al4(MnFe)3Si2 and Mg2Si, while pure Si is only present in the alloy containing lower magnesium content. Increasing Mg content leads to increasing the amount of Mg2Si, but decreasing the amount of Al1.9CuMg4.1Si3.3 and Al4(MnFe)3Si2. During the following homogenization process, Al1.9CuMg4.1Si3.3 is completely dissolved, Al4(MnFe)3Si2 and pure Si remain unchanged. After rolling and final heat treatment, the constituents in the alloys change no longer.展开更多
Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction interme...Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction intermediate in this reaction, creating a different reaction pathway. The formation of crystalline phases and characteristic morphology of the co-precipitated precursors during the co-precipitation step were important factors in obtaining an efficient Cu/ZnO catalyst with a high dispersion of metallic copper,which is one of the main active sites for methanol synthesis. The acidic properties of the Cu/ZnO catalyst were also revealed as important factors, since alcohol esterification is considered the rate-limiting step in alcohol-assisted low-temperature methanol synthesis. As a consequence, bifunctionality of the Cu/ZnO catalyst such as metallic copper and acidic properties was required for this reaction. In this respect, the copper content（X） strongly affected the catalytic activity of the Cu/ZnO;catalysts, and accordingly, the Cu/ZnO;.5 catalyst with a high copper dispersion and sufficient acid sites exhibited the best catalytic performance in this reaction.展开更多
It is discovered that there is the concentrative phenomenon of relative content ratios of Cu, Pb and Zn in soil by studying their parageneous association in soil, meteorites and rocks with the relative content ratios....It is discovered that there is the concentrative phenomenon of relative content ratios of Cu, Pb and Zn in soil by studying their parageneous association in soil, meteorites and rocks with the relative content ratios. This not only is helpful to understand the trends of Cu, Cd and Zn enriched and dispersed in the evolution course of earth matter, but also provides evidence for geochemical self-organization that there may be in the process of Cu, Pb and Zn translation and distribution.展开更多
基金Sponsored by National Science and Technology Support Plan of China (2007BAE51B02)
文摘The precipitation characteristics and effect on strengthening mechanism of Cu-rich phases during short-time and long-time aging for Super 304H steels with different Cu content were investigated using X-ray diffraction （XRD）, scanning electron microscope （SEM） and transmission electron microscope （TEM）. The results show that the size of Cu-rich phase particles increases, the interspace of Cu-rich phase particles decreases and the density of Curich phases increases with the increase of Cu content during short-time aging （approximately 800 h） at 650℃ for Super 304H steels. During long-time aging （more than 2 000 h） at 650 ℃, Cu-rich phase precipitates sufficiently and the strengthening effect of Cu-rich phase is preferable in Super 304H steel containing Cu of 4%. The strengthening effect of Cu-rich phase in Super 304H steels containing Cu of 2.2% or 5% is weaker than that with Cu of 4% during long-time aging （more than 2 000 h）.
基金Universiti Teknikal Malaysia Melaka (UTeM) and the Ministry of Education Malaysia for financial support of this studyUniversiti Kebangsaan Malaysia (UKM) for the financial support under research grants GUP-2012-040 and AP-2012-014
文摘The effects of Cu content on the microstructure and mechanical properties of thixoformed Al-6Si-xCu-0.3Mg(x= 3,4,5and 6,mass fraction,%) alloys were studied.The samples were thixoformed at 50%liquid content and several of the samples were treated with the T6 heat treatment.The samples were then examined by optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive X-ray(EDX) spectroscopy and X-ray diffraction(XRD) analysis,as well as hardness and tensile tests.The results show that the cooling slope casting and thixoforming process promote the formation of very fine and well distributed intermetallic compounds in the aluminium matrix and the mechanical properties of the alloys increase considerably compared with the permanent mould casting.The results also reveal that as the Cu content in the alloy increases,the hardness and tensile strength of the thixoformed alloys also increase.The ultimate tensile strength,yield strength and elongation to fracture of the thixoformed heat-treated Al-6Si-3Cu-0.3Mg alloy are 298 MPa,201 MPa and 4.5%,respectively,whereas the values of the thixoformed heat-treated alloy with high Cu content(6%) are 361 MPa,274 MPa and 1.1%,respectively.The fracture of the thixoformed Al-6Si-3Cu-0.3Mg alloy shows a dimple rupture,whereas in the alloy that contains the highest Cu content(6%),a cleavage fracture is observed.
基金The authors would like to thank the financial support from the National Key R&D Program of China(No.2016YFB0301003).
文摘A systematic study on how Cu content affects the microstructure and mechanical properties of rheo-diecasting Al-6Zn-2Mg-xCu alloys during solution treatment and ageing heat treatment was conducted.The swirled enthalpy equilibrium device(SEED)was adopted to prepare the semi-solid slurry of Al-6Zn-2Mg-xCu alloys.The microstructure development and mechanical properties were studied using optical microscopy(OM),scanning electron microscopy(SEM),X-ray diffraction(XRD),differential scanning calorimetry(DSC),as well as hardness and tensile testing.The grain boundary and shape factor were calculated using image processing software(Image-Pro Plus 6.0).Results show that the alloys are composed of typical globular primaryα-Al grains,eutectic phases,and smaller secondaryα-Al grains.After solution and ageing heat treatment,the eutectic phases are dissolved into Al matrix when the Cu content is lower than 1.5wt.%,while some eutectic phases transform into Al_(2)CuMg(S)phases and remain at grain boundaries when Cu content reaches 2wt.%.T6 heat treatment significantly enhances the mechanical properties of rheo-diecasting Al-6Zn-2Mg-xCu alloys.When Cu concentration is 0.5wt.%-1.5wt.%,the ultimate tensile strength,yield strength and elongation of T6 treated alloys rise to around 500 MPa,420 MPa,and 18%,respectively.
基金financially supported by the National Key Research and Development Program of China(Nos.2018YFC1106601 and 2016YFC1100601)the LiaoNing Revitalization Talents Program(No.XLYC1807069)+1 种基金the National Natural Science Foundation of China(Nos.51631009 and 31870954)the Key Projects for Foreign Cooperation of Bureau of International Cooperation Chinese Academy of Sciences(No.174321KYSB2018000)。
文摘In order to reduce implant-related infections and improve early osseointegration,we performed HF+anodic oxidation on the surface of the new antibacterial Ti-Cu alloy to make the titanium-based implants have a micro/submicron structure.On this basis,a series of surface-modified Ti-x Cu alloys with different Cu contents(3,5 and 7 wt%)were fabricated and a comprehensive study was conducted on MC3 T3-E1 cell adhesion,proliferation,apoptosis and its antibacterial activity against Staphylococcus aureus.Results showed that the Ti-x Cu alloys by HF etching+anodized possessed multifunctional characteristics of antibiofilm and antibacterial abilities,excellent biocompatibility and osteogenesis promoting abilities.Increment of Cu content significantly contributed to the antibacterial and osteogenic properties of HF etching+anodized Ti-Cu alloys.Cell proliferation rates of HF etching+anodized Ti-7 Cu alloys were lower than those of Ti-3 Cu and Ti-5 Cu alloys,while the early cell apoptosis rates were higher than Ti-3 Cu and Ti-5 Cu groups.All the above results finally presented that the HF etching+anodized Ti-5 Cu alloy exhibited extremely strong antibacterial properties,good biological compatibility and osteogenic ability,as well as the most excellent ductility and corrosion resistance,providing a great potential application for the future dental implantation.
基金Supported by Jilin Provincial Science and Technology Development Program(20110403)Water Pollution Control and Management Project(2012ZX07201001)
文摘In order to understand the heavy metal contamination of Cu in the farmland soil in the suburbs of Changchun City,and reveal the distribution of Cu content of soil in different farmland types,we use the methods field survey and laboratory analysis,to analyze the Cu content of soil in different farmland types in the suburbs of Changchun City. Using SPSS statistical analysis software and ORING mapping software,we process the data of Cu content in 60 sampling points and draw the normal distribution map,and then analyze the distribution of Cu content of soil in different land use types. The results show that the Cu content of the farmland soil in the suburbs of Changchun City is between 41. 71 mg /kg and 116. 77 mg /kg,with an average of 53. 35 mg /kg,and the content in all sampling points is higher than the background value; in terms of the Cu content of soil,different land use types are sequenced in descending order(vegetable field > paddy > dry land).
基金The Guangdong Province Natural Science Foundation,2023A1515011558the Liaoning Natural Science Foundation,2025-MS-047+3 种基金the State Key Laboratory of Solid Lubrication Fund,LSL-2204the Open Fund of The Key Laboratory for Metallurgical Equipment and Control Technology of Ministry of Education in Wuhan University of Science and Technology,MECOF2024B02the Fundamental Research Funds for the Central Universities,N2403019the Tribology Science Fund of the State Key Laboratory of Tribology in Advanced Equipment,SKLTKF24B15.
文摘The AgCu alloy is widely used in numerous industries such as electronics and electrical engineering due to its excellent electrical conductivity,thermal conductivity,and workability.However,the friction problems during its service can seriously affect the operational stability and service life.Therefore,it is of great significance to deeply explore the friction and wear behavior of the AgCu alloy.In this study,the molecular dynamics simulation method was employed to conduct an in-depth investigation of the friction and wear behavior of AgCu alloy with different friction depths,velocities,and Cu contents.It found that as the depth increases,the contact area enlarges,and the atomic packing,phase transformation,and dislocations increase,resulting in a roughly linear increase in the average and normal friction force.The characteristic of this wear mechanism is that it will create grooves on the surface and cause material transfer.At friction speeds of 0.5Å/ps,1Å/ps,and 1.5Å/ps,the average friction force increases with the increase of speed,accompanied by expanded strain localization and reduced twinning with intensified temperature under dynamic loading.The content of the Cu has a significant impact on the friction behavior.When the content increases,the softening of the alloy leads to a linear decrease in the average friction force.At the same time,the plasticity is enhanced,the strain region expands,and the disordered atomic structures increase.The results of this study provide an important theoretical basis for a deep understanding of the friction and wear mechanism of the AgCu alloy and the optimization of its performance.
基金Project(2002AA331050) supported by Hi-tech Research and Development Program of China project(0208) supported by Science and Technology Research of Ministry of Education of China
文摘By means of scanning electron microscopy(SEM), energy dispersive spectrum(EDS), X-ray diffractometry(XRD) and metallographic analysis, the effects of variation of magnesium content on phase constituents of Al-Mg-Si-Cu alloys were investigated. The results indicate that the constituents formed during casting alloys are main Al1.9CuMg4.1Si3.3,Al4(MnFe)3Si2 and Mg2Si, while pure Si is only present in the alloy containing lower magnesium content. Increasing Mg content leads to increasing the amount of Mg2Si, but decreasing the amount of Al1.9CuMg4.1Si3.3 and Al4(MnFe)3Si2. During the following homogenization process, Al1.9CuMg4.1Si3.3 is completely dissolved, Al4(MnFe)3Si2 and pure Si remain unchanged. After rolling and final heat treatment, the constituents in the alloys change no longer.
基金supported by C1 Gas Refinery Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science,ICT & Future Planning (2015M3D3A1A01064908)
文摘Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction intermediate in this reaction, creating a different reaction pathway. The formation of crystalline phases and characteristic morphology of the co-precipitated precursors during the co-precipitation step were important factors in obtaining an efficient Cu/ZnO catalyst with a high dispersion of metallic copper,which is one of the main active sites for methanol synthesis. The acidic properties of the Cu/ZnO catalyst were also revealed as important factors, since alcohol esterification is considered the rate-limiting step in alcohol-assisted low-temperature methanol synthesis. As a consequence, bifunctionality of the Cu/ZnO catalyst such as metallic copper and acidic properties was required for this reaction. In this respect, the copper content（X） strongly affected the catalytic activity of the Cu/ZnO;catalysts, and accordingly, the Cu/ZnO;.5 catalyst with a high copper dispersion and sufficient acid sites exhibited the best catalytic performance in this reaction.
基金The Projecton Environmental Background Value of Soilin China(75-60-01-01 )
文摘It is discovered that there is the concentrative phenomenon of relative content ratios of Cu, Pb and Zn in soil by studying their parageneous association in soil, meteorites and rocks with the relative content ratios. This not only is helpful to understand the trends of Cu, Cd and Zn enriched and dispersed in the evolution course of earth matter, but also provides evidence for geochemical self-organization that there may be in the process of Cu, Pb and Zn translation and distribution.
