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 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 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
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
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.
