A novel process for manufacturing A1-0.70Fe-0.24Cu alloy conductor was proposed, which includes horizontal continuous casting and subsequent continuous extrusion forming （Conform）. The mechanical properties, electri...A novel process for manufacturing A1-0.70Fe-0.24Cu alloy conductor was proposed, which includes horizontal continuous casting and subsequent continuous extrusion forming （Conform）. The mechanical properties, electrical conductivity and the compressed creep behaviour of the alloy were studied. The results indicate that the Conform process induces obvious grain refinement, strain-induced precipitation of AI7CuzFe phase and the transformation of crystal orientation distribution. The processed alloy has good comprehensive mechanical properties and electrical conductivity. Moreover, a better creep resistance under the conditions of 90 ~C and 76 MPa is shown compared with pure A1 and annealed copper, and the relationship between primary creep strain and time may comply with the logarithmic law. The enhanced properties are attributed to the grain refinement as well as the fine and homogeneously distributed thermally stable A1Fe and A17Cu2Fe precipitation phases.展开更多
Through the experiment of natural seawater exposure corrosion, the antifouling properties of the plate specimens of 90Cu 10Ni alloy were studied, which were processed by different deformations, annealing treatments an...Through the experiment of natural seawater exposure corrosion, the antifouling properties of the plate specimens of 90Cu 10Ni alloy were studied, which were processed by different deformations, annealing treatments and surface treatments. The results indicate that after exposure corrosion for half a year, the antifouling properties of the specimens are quite different. The specimens processed by suitable deformations, annealing treatment at 650?℃ and pretreatment of surface film possess both good corrosion resistance and antifouling properties. However, the specimens processed by different deformations and annealing treatment at 450?℃ possess lower corrosion resistance, although they are also treated by the pretreatment of surface film; their antifouling properties change with different deformations. The relationships among the corrosion morphology and microstructure with the antifouling property of 90Cu 10Ni alloy are observed under the scanning electron microscopy (SEM).展开更多
The Mg65Cu25Y10 melts were quenched at a temperature of 973 K under various pressures in the range of 2-5 GPa and ambient pressure. The microstructure of the solidified specimens has been investigated by X-ray diffrac...The Mg65Cu25Y10 melts were quenched at a temperature of 973 K under various pressures in the range of 2-5 GPa and ambient pressure. The microstructure of the solidified specimens has been investigated by X-ray diffraction, transmission electron microscope and electron probe microanalysis. Experimental results show that the pressure has a great influence on the solidification microstructure of the Mg65Cu25Y10. At ambient pressure, the solidification products are Mg2(Cu,Y) and a very small amount of Y2O3 inclusion. As the pressure is above 2 GPa, a new Cu2(Y,Mg) phase appears, while Y2O3 is not observed at the pressure of 3, 4 and 5 GPa. When the pressure increases from 2 GPa to 5 GPa, the grain sizes of Mg2(Cu,Y) and Cu2(Y,Mg) decrease from 125, 96 nm to 80, 7 nm, respectively. The mechanisms for the effects of the pressure on the phase evolution and microstructure during solidification process of Mg65Cu25Y10 alloy have been discussed.展开更多
The microstructure evolution and formability of Ti-10V-2Fe-3Al alloy related to the initial microstructures and processing variables were investigated during hot forming process. The experimental results show that the...The microstructure evolution and formability of Ti-10V-2Fe-3Al alloy related to the initial microstructures and processing variables were investigated during hot forming process. The experimental results show that the α-phase growth is controlled by solute diffusion during the heat treatment processes. Four different microstructures were established by combinations of several heat treatments, and Ti-10V-2Fe-3Al alloy shows excellent formability both above and below the β transus temperature. The alloy possesses low deformation resistance and active restoration mechanism during the deformation. A constitutive equation describing the hot deformation behavior of Ti-10V-2Fe-3Al alloy was obtained. Higher fl ow stress was observed for the acicular morphology of α phase in microstructures with large aspect ratios as compared with that of small aspect ratios. Due to the dynamic recovery in soft β phase, and the dynamic recrystallization and breakage of acicular α-phase, fl ow softening occurred signifi cantly during deformation. Dynamic recrystallization also occurred especially in the severely deformed regions of forged parts.展开更多
Crystallization behavior of amorphous Zr 65 Cu 25 Al 10 alloy under isothermal annealing condition was investigated by DSC and XRD. It is found that two exothermic peaks appear in the DSC curve of amorphous Zr 65 Cu 2...Crystallization behavior of amorphous Zr 65 Cu 25 Al 10 alloy under isothermal annealing condition was investigated by DSC and XRD. It is found that two exothermic peaks appear in the DSC curve of amorphous Zr 65 Cu 25 Al 10 alloy, indicating that the crystallization proceeds through double stage mode. The crystallization process of amorphous Zr 65 Cu 25 Al 10 alloy under isothermal annealing condition is mainly controlled by nucleation and one dimensional growth with the crystallized volume fraction smaller than 70%. With the crystallized volume fraction ranging from 70% to 90%, crystallization process is mainly dominated by the growth of three dimensional pre existing quench in nuclei. And when the crystallized volume fraction reaches above 90%, transient nucleation becomes the master of the crystallization process.展开更多
The rheological behavior of partially solidified Al-10% Cu alloy is in-vestigated.It is found that the slurry presents the character of a psoudoplastie fluid inisothermally holding and the apparent viscosity increases...The rheological behavior of partially solidified Al-10% Cu alloy is in-vestigated.It is found that the slurry presents the character of a psoudoplastie fluid inisothermally holding and the apparent viscosity increases with increasing cooling ratein continuously cooling.The effect of cooling rate on the apparent viscosity decreasesin high stirring rate range.The measured value of apparent viscosity is influenced bythe diameter of the screw propeller.展开更多
Effect of β-flecks on properties of tensile elongation and low cycle.fatigue life at room tern. perature for Ti-10V-2Fe-3Al alloy has been investigated.The cracks along initial β-grain boundaries in the β-fleck reg...Effect of β-flecks on properties of tensile elongation and low cycle.fatigue life at room tern. perature for Ti-10V-2Fe-3Al alloy has been investigated.The cracks along initial β-grain boundaries in the β-fleck region may propagate to form intergranular brittle fracture.Under alternating load,the β-fleck often becomes a fatigue origin.While under higher strain,the cracks initiate and propagate to fracture early at the original β-grain boundaries in β-fleck region and at α-grain boundaries.展开更多
The bulk glassy Cu 60 Zr 30 Ti 10 alloy with a diameter up to 4 mm and a length of 70 mm containing nanocrystalline phase was successfully developed by using copper mold casting method. The temperature interval of the...The bulk glassy Cu 60 Zr 30 Ti 10 alloy with a diameter up to 4 mm and a length of 70 mm containing nanocrystalline phase was successfully developed by using copper mold casting method. The temperature interval of the supercooled liquid region before crystallization is above 37 K. The glass transition temperature ( T g) and the reduced glass transition temperature ( T g/ T l) of the cast bulk glassy Cu 60 Zr 30 Ti 10 alloy are 713 K and 0.62. The cast bulk glassy alloy, which has high glassy forming ability, shows expected mechanical properties. The elastic modulus, yield strength, fracture strength and elongation including elastic elongation are 114 GPa, 1 785 MPa, 2 150 MPa and 3.3% respectively in compressive deformation, and 112 GPa, 1 780 MPa, 2 000 MPa and 1.9% respectively in tensile deformation. High resolution transmission electron microscope (HRTEM) and nano beam electron diffraction (NBED) studies indicate that the cast metallic bulk glassy Cu 60 Zr 30 Ti 10 alloy consists of nanocrystals with a size of 4 nm embedded in glassy matrix. The nanoparticle is identified as CuZr and has point space group symmetry of pm3m and its lattice parameter is a =0.3 262 nm . The nanocrystalline phase grew up to 10 nm upon annealing at 430 ℃ for 10 min and caused the alloy brittle.展开更多
Crystallization behavior of amorphous Zr 70 Cu 20 Ni 10 alloy isothermally annealed at 380 ℃ was first investigated by employing the differential scanning calorimetry (DSC) and transmission electron microscopy (TEM)....Crystallization behavior of amorphous Zr 70 Cu 20 Ni 10 alloy isothermally annealed at 380 ℃ was first investigated by employing the differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). It has been found that an exothermic peak appears in the DSC trace when the annealing time is about 17～18 min, indicating a certain phase transformation occurs in the matrix of amorphous Zr 70 Cu 20 Ni 10 alloy. Meanwhile, isothermal annealing experiments for amorphous Zr 70 Cu 20 Ni 10 alloy ranging from 360 ℃ to 400 ℃ with a temperature interval of 10 ℃ were also carried out, from which no exothermic reaction can be observed except for the case of 380 ℃. This behavior indicates that the phase transformation during isothermal annealing of amorphous Zr 70 Cu 20 Ni 10 alloy is strongly temperature and time dependent. Further investigations are required to reveal the nature of such phenomenon.展开更多
基金Project(20130161110007) supported by the Doctoral Program of Higher Education of China
文摘A novel process for manufacturing A1-0.70Fe-0.24Cu alloy conductor was proposed, which includes horizontal continuous casting and subsequent continuous extrusion forming （Conform）. The mechanical properties, electrical conductivity and the compressed creep behaviour of the alloy were studied. The results indicate that the Conform process induces obvious grain refinement, strain-induced precipitation of AI7CuzFe phase and the transformation of crystal orientation distribution. The processed alloy has good comprehensive mechanical properties and electrical conductivity. Moreover, a better creep resistance under the conditions of 90 ~C and 76 MPa is shown compared with pure A1 and annealed copper, and the relationship between primary creep strain and time may comply with the logarithmic law. The enhanced properties are attributed to the grain refinement as well as the fine and homogeneously distributed thermally stable A1Fe and A17Cu2Fe precipitation phases.
文摘Through the experiment of natural seawater exposure corrosion, the antifouling properties of the plate specimens of 90Cu 10Ni alloy were studied, which were processed by different deformations, annealing treatments and surface treatments. The results indicate that after exposure corrosion for half a year, the antifouling properties of the specimens are quite different. The specimens processed by suitable deformations, annealing treatment at 650?℃ and pretreatment of surface film possess both good corrosion resistance and antifouling properties. However, the specimens processed by different deformations and annealing treatment at 450?℃ possess lower corrosion resistance, although they are also treated by the pretreatment of surface film; their antifouling properties change with different deformations. The relationships among the corrosion morphology and microstructure with the antifouling property of 90Cu 10Ni alloy are observed under the scanning electron microscopy (SEM).
基金supported by the National Natural Science Foundation of China(Grant number:50071060)the National Development Project for Basic Scientific Research(Grant number:G2000067201).
文摘The Mg65Cu25Y10 melts were quenched at a temperature of 973 K under various pressures in the range of 2-5 GPa and ambient pressure. The microstructure of the solidified specimens has been investigated by X-ray diffraction, transmission electron microscope and electron probe microanalysis. Experimental results show that the pressure has a great influence on the solidification microstructure of the Mg65Cu25Y10. At ambient pressure, the solidification products are Mg2(Cu,Y) and a very small amount of Y2O3 inclusion. As the pressure is above 2 GPa, a new Cu2(Y,Mg) phase appears, while Y2O3 is not observed at the pressure of 3, 4 and 5 GPa. When the pressure increases from 2 GPa to 5 GPa, the grain sizes of Mg2(Cu,Y) and Cu2(Y,Mg) decrease from 125, 96 nm to 80, 7 nm, respectively. The mechanisms for the effects of the pressure on the phase evolution and microstructure during solidification process of Mg65Cu25Y10 alloy have been discussed.
基金Funded by the National Natural Science Foundation of China(Nos.51222405 and 51474063)
文摘The microstructure evolution and formability of Ti-10V-2Fe-3Al alloy related to the initial microstructures and processing variables were investigated during hot forming process. The experimental results show that the α-phase growth is controlled by solute diffusion during the heat treatment processes. Four different microstructures were established by combinations of several heat treatments, and Ti-10V-2Fe-3Al alloy shows excellent formability both above and below the β transus temperature. The alloy possesses low deformation resistance and active restoration mechanism during the deformation. A constitutive equation describing the hot deformation behavior of Ti-10V-2Fe-3Al alloy was obtained. Higher fl ow stress was observed for the acicular morphology of α phase in microstructures with large aspect ratios as compared with that of small aspect ratios. Due to the dynamic recovery in soft β phase, and the dynamic recrystallization and breakage of acicular α-phase, fl ow softening occurred signifi cantly during deformation. Dynamic recrystallization also occurred especially in the severely deformed regions of forged parts.
文摘Crystallization behavior of amorphous Zr 65 Cu 25 Al 10 alloy under isothermal annealing condition was investigated by DSC and XRD. It is found that two exothermic peaks appear in the DSC curve of amorphous Zr 65 Cu 25 Al 10 alloy, indicating that the crystallization proceeds through double stage mode. The crystallization process of amorphous Zr 65 Cu 25 Al 10 alloy under isothermal annealing condition is mainly controlled by nucleation and one dimensional growth with the crystallized volume fraction smaller than 70%. With the crystallized volume fraction ranging from 70% to 90%, crystallization process is mainly dominated by the growth of three dimensional pre existing quench in nuclei. And when the crystallized volume fraction reaches above 90%, transient nucleation becomes the master of the crystallization process.
文摘The rheological behavior of partially solidified Al-10% Cu alloy is in-vestigated.It is found that the slurry presents the character of a psoudoplastie fluid inisothermally holding and the apparent viscosity increases with increasing cooling ratein continuously cooling.The effect of cooling rate on the apparent viscosity decreasesin high stirring rate range.The measured value of apparent viscosity is influenced bythe diameter of the screw propeller.
文摘Effect of β-flecks on properties of tensile elongation and low cycle.fatigue life at room tern. perature for Ti-10V-2Fe-3Al alloy has been investigated.The cracks along initial β-grain boundaries in the β-fleck region may propagate to form intergranular brittle fracture.Under alternating load,the β-fleck often becomes a fatigue origin.While under higher strain,the cracks initiate and propagate to fracture early at the original β-grain boundaries in β-fleck region and at α-grain boundaries.
文摘The bulk glassy Cu 60 Zr 30 Ti 10 alloy with a diameter up to 4 mm and a length of 70 mm containing nanocrystalline phase was successfully developed by using copper mold casting method. The temperature interval of the supercooled liquid region before crystallization is above 37 K. The glass transition temperature ( T g) and the reduced glass transition temperature ( T g/ T l) of the cast bulk glassy Cu 60 Zr 30 Ti 10 alloy are 713 K and 0.62. The cast bulk glassy alloy, which has high glassy forming ability, shows expected mechanical properties. The elastic modulus, yield strength, fracture strength and elongation including elastic elongation are 114 GPa, 1 785 MPa, 2 150 MPa and 3.3% respectively in compressive deformation, and 112 GPa, 1 780 MPa, 2 000 MPa and 1.9% respectively in tensile deformation. High resolution transmission electron microscope (HRTEM) and nano beam electron diffraction (NBED) studies indicate that the cast metallic bulk glassy Cu 60 Zr 30 Ti 10 alloy consists of nanocrystals with a size of 4 nm embedded in glassy matrix. The nanoparticle is identified as CuZr and has point space group symmetry of pm3m and its lattice parameter is a =0.3 262 nm . The nanocrystalline phase grew up to 10 nm upon annealing at 430 ℃ for 10 min and caused the alloy brittle.
文摘Crystallization behavior of amorphous Zr 70 Cu 20 Ni 10 alloy isothermally annealed at 380 ℃ was first investigated by employing the differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). It has been found that an exothermic peak appears in the DSC trace when the annealing time is about 17～18 min, indicating a certain phase transformation occurs in the matrix of amorphous Zr 70 Cu 20 Ni 10 alloy. Meanwhile, isothermal annealing experiments for amorphous Zr 70 Cu 20 Ni 10 alloy ranging from 360 ℃ to 400 ℃ with a temperature interval of 10 ℃ were also carried out, from which no exothermic reaction can be observed except for the case of 380 ℃. This behavior indicates that the phase transformation during isothermal annealing of amorphous Zr 70 Cu 20 Ni 10 alloy is strongly temperature and time dependent. Further investigations are required to reveal the nature of such phenomenon.
