The in situ filamentary composites based on the Cu-10Ag and Cu-10Ag-Ce alloys were prepared. The microstructure and properties of the composites were studied. The effects of Ce addition on the microstructure as cast, ...The in situ filamentary composites based on the Cu-10Ag and Cu-10Ag-Ce alloys were prepared. The microstructure and properties of the composites were studied. The effects of Ce addition on the microstructure as cast, including refining Cu grains and the Ag filaments, increasing the proportion of (Cu+Ag) eutectic and decreasing the proportion of the Ag precipitate, were researched. The average size of the Ag filaments in the composites could be approached by a formula: d=C·exp(-0.228η), here C is a coefficient related to the size of the original grains and 1500 nm for Cu-10Ag and 800 nm for Cu-10Ag-Ce. A two-stage strain strengthening effect was found for the deformed composites, that is the dislocation strengthening at low strain stage and the ultra-fine Ag filaments or interface strengthening at the high strain stage. The intermediate heat treatment at lower temperature further refined the Ag filaments and therefore improved the properties. The high strengthening rate of Ce addition on Cu-10Ag alloy attributed the refining effect to Cu grains and Ag filaments. The typical properties of the heavy deformed composites with 1 IHT reached to UTS=1500 MPa with conductivity 62% IACS for the Cu-10Ag alloy and UTS=1550 MPa with conductivity 65% IACS for the Cu-10Ag-Ce alloy, respectively.展开更多
The influences of rare earth elements（cerium and lanthanum） on the microstructure and phases of Al-3.0 wt%Mg alloys used for electromagnetic shielding wire were characterized by scanning electron microscopy（SEM）, ...The influences of rare earth elements（cerium and lanthanum） on the microstructure and phases of Al-3.0 wt%Mg alloys used for electromagnetic shielding wire were characterized by scanning electron microscopy（SEM）, energy-dispersive spectroscopy（EDS）, X-ray diffraction（XRD） and differential scanning calorimetry（DSC）. The mechanical properties and electrical resistivity were also investigated. The results indicated that a certain content of rare earth could improve the purification of the aluminum molten, enhance the strength, and reduce the electrical resistivity of Al-3.0 wt%Mg alloys. The strength reached the top value when RE content was 0.3 wt% while the alloy with 0.2 wt% RE addition had the smallest electrical resistivity. The elongation varied little when RE addition was no more than 0.2 wt%. But the excessive addition of rare earth would be harmful to the microstructure and properties of Al-3.0 wt%Mg alloys.展开更多
文摘The in situ filamentary composites based on the Cu-10Ag and Cu-10Ag-Ce alloys were prepared. The microstructure and properties of the composites were studied. The effects of Ce addition on the microstructure as cast, including refining Cu grains and the Ag filaments, increasing the proportion of (Cu+Ag) eutectic and decreasing the proportion of the Ag precipitate, were researched. The average size of the Ag filaments in the composites could be approached by a formula: d=C·exp(-0.228η), here C is a coefficient related to the size of the original grains and 1500 nm for Cu-10Ag and 800 nm for Cu-10Ag-Ce. A two-stage strain strengthening effect was found for the deformed composites, that is the dislocation strengthening at low strain stage and the ultra-fine Ag filaments or interface strengthening at the high strain stage. The intermediate heat treatment at lower temperature further refined the Ag filaments and therefore improved the properties. The high strengthening rate of Ce addition on Cu-10Ag alloy attributed the refining effect to Cu grains and Ag filaments. The typical properties of the heavy deformed composites with 1 IHT reached to UTS=1500 MPa with conductivity 62% IACS for the Cu-10Ag alloy and UTS=1550 MPa with conductivity 65% IACS for the Cu-10Ag-Ce alloy, respectively.
基金Funded by the National Natural Science Foundation of China(No.51379070)the Fundamental Research Funds for the Central Universities(No.2017B40314)
文摘The influences of rare earth elements（cerium and lanthanum） on the microstructure and phases of Al-3.0 wt%Mg alloys used for electromagnetic shielding wire were characterized by scanning electron microscopy（SEM）, energy-dispersive spectroscopy（EDS）, X-ray diffraction（XRD） and differential scanning calorimetry（DSC）. The mechanical properties and electrical resistivity were also investigated. The results indicated that a certain content of rare earth could improve the purification of the aluminum molten, enhance the strength, and reduce the electrical resistivity of Al-3.0 wt%Mg alloys. The strength reached the top value when RE content was 0.3 wt% while the alloy with 0.2 wt% RE addition had the smallest electrical resistivity. The elongation varied little when RE addition was no more than 0.2 wt%. But the excessive addition of rare earth would be harmful to the microstructure and properties of Al-3.0 wt%Mg alloys.
