Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with a copper sheet as interlayer was carried out.Microstructures of the joint were studied by optical microscopy(OM),scanning electron microscopy...Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with a copper sheet as interlayer was carried out.Microstructures of the joint were studied by optical microscopy(OM),scanning electron microscopy(SEM) and X-ray diffractometry(XRD).In addition,the mechanical properties of the joint were evaluated by tensile test and the microhardness was measured.These two alloys were successfully welded by adding copper transition layer into the weld.Solid solution with a certain thickness was located at the interfaces between weld and base metal in both sides.Regions inside the weld and near the stainless steel were characterized by solid solution of copper with TiFe2 intermetallics dispersedly distributed in it.While weld near titanium alloy contained Ti-Cu and Ti-Fe-Cu intermetallics layer,in which the hardness of weld came to the highest value.Brittle fracture occurred in the intermetallics layer when the joint was stretched.展开更多
The intramolecular reductive coupling reaction of 1,6-bis(subshtuted indolyl)hexane-1,6-dione using zero-valent titanium reagent as catalyst proderes the novel photochromic 1,2-diheterocyclic cyclohexenes 2, together ...The intramolecular reductive coupling reaction of 1,6-bis(subshtuted indolyl)hexane-1,6-dione using zero-valent titanium reagent as catalyst proderes the novel photochromic 1,2-diheterocyclic cyclohexenes 2, together with unexpected compounds 3展开更多
The microstructural evolution, mechanical properties and fracture mechanism of a Ti.5Al.5Mo.5V.3Cr.1Zr (Ti-55531) alloy after solution (760.820℃) plus aging (580.640℃) treatments were investigated. The results show ...The microstructural evolution, mechanical properties and fracture mechanism of a Ti.5Al.5Mo.5V.3Cr.1Zr (Ti-55531) alloy after solution (760.820℃) plus aging (580.640℃) treatments were investigated. The results show that the volume fraction of the primary α(αp) phase decreases with the increase of solution temperature, and the length of the secondary α phase (αs) decreases while its width increases with the increase of aging temperature. Yield and tensile strengths decrease with the increase of solution temperature, while increase with the increase of aging temperature. A good balance of tensile strength and ductility of the alloy is obtained under solution of 800℃ for 2 h plus aging of 640℃ for 8 h, in which the tensile strength is 1434 MPa and the elongation is 7.7%. The coarsening αs phase makes crack propagation paths deflected and tortuous, which increases the crack propagation resistance and improves the ductility and fracture toughness.展开更多
Ti-6AI-4V, among the Ti alloys, is the most widely used. In the present work, the behavior of Ti-6AI-4V alloy has been investigated by the uniaxial hot isothermal compression tests and a series of dilatometric experim...Ti-6AI-4V, among the Ti alloys, is the most widely used. In the present work, the behavior of Ti-6AI-4V alloy has been investigated by the uniaxial hot isothermal compression tests and a series of dilatometric experiments were also carried out to determine the transformation temperatures at different cooling rates. Specimens for hot compression tests were homogenized at 1050℃ for 10 min and then quickly cooled to different straining temperatures from 1050 to 850℃. Cooling rates were chosen fast enough to prevent high temperature transformation during cooling. Compression tests were conducted at temperatures from 1050 to 850℃ in steps of 50℃ at constant true strain rates of 10-3 or 10-2 s-1. The apparent activation energy for compression in two-phase region was calculated 420 kJ·mol-1. Partial globularization of a phase was observed in the specimen deformed at low strain rates and at temperatures near the transformation zone and annealed after deformation.展开更多
The influence of different lubricants on the deformation behaviour of IN 718 alloy was studied. The results show that, with the improvement of lubrication condition, the deformation of the alloy tends to be homogeneou...The influence of different lubricants on the deformation behaviour of IN 718 alloy was studied. The results show that, with the improvement of lubrication condition, the deformation of the alloy tends to be homogeneous, and the resistance of deformation decreases. Consequently, FR 2 glass lubricant is considered to be an ideal choice when the relationship between stress and strain of IN 718 alloy is measured by means of hot compression experiment.展开更多
The purpose of this study was to test the hypothesis that the combination of micro-arc oxidation and alkali heatment （MAH） would improve the cytocompatibility of a newly designed Ti-24Nb-4Zr-8Sn alloy. In this study...The purpose of this study was to test the hypothesis that the combination of micro-arc oxidation and alkali heatment （MAH） would improve the cytocompatibility of a newly designed Ti-24Nb-4Zr-8Sn alloy. In this study, commercially pure titanium （cp Ti） and Ti-24Nb-4Zr-8Sn were used. Surface modification of Ti-24Nb- 4Zr-8Sn by a two-step treatment of micro-arc oxidation （MAO） and alkali heatment was reported. Surface characterizations were performed by scanning electron microscopy （SEM）, thin film X-ray diffraction （TF-XRD） and X-ray photoelectron spectroscopy （XPS）. The MAH layer consisted of finer crystals and possessed a higher degree of crystallity and stability than the MAO layer. A biocompatibility study on treated and untreated Ti- 24Nb-4Zr-8Sn in comparison with cp Ti was carried out to investigate the effect of the different surfaces on the bone integration property in vitro. The cellular assays revealed that the MAO and MAH layer favored the initial adhesion of MC3T3-E1 cells and that the growth rate of MC3T3-E1 cells on MAH layer was significantly higher than that on the conventional MAO-treated layer after 3-day and 5-day incubation, demonstrating the greater potential of the hybrid treatment of micro-arc oxidation followed with alkali heatment as a novel surface modification method for implanting materials.展开更多
文摘Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with a copper sheet as interlayer was carried out.Microstructures of the joint were studied by optical microscopy(OM),scanning electron microscopy(SEM) and X-ray diffractometry(XRD).In addition,the mechanical properties of the joint were evaluated by tensile test and the microhardness was measured.These two alloys were successfully welded by adding copper transition layer into the weld.Solid solution with a certain thickness was located at the interfaces between weld and base metal in both sides.Regions inside the weld and near the stainless steel were characterized by solid solution of copper with TiFe2 intermetallics dispersedly distributed in it.While weld near titanium alloy contained Ti-Cu and Ti-Fe-Cu intermetallics layer,in which the hardness of weld came to the highest value.Brittle fracture occurred in the intermetallics layer when the joint was stretched.
文摘The intramolecular reductive coupling reaction of 1,6-bis(subshtuted indolyl)hexane-1,6-dione using zero-valent titanium reagent as catalyst proderes the novel photochromic 1,2-diheterocyclic cyclohexenes 2, together with unexpected compounds 3
基金Project(SKLSP201853) supported by the Fund of the State Key Laboratory of Solidification Processing in NWPU,ChinaProject(51625505) supported by the National Science Fund for Distinguished Young Scholars of China+1 种基金Project(U1537203) supported by the Key Program Project of the Joint Fund of Astronomy and National Natural Science Foundation of ChinaProject(KYQD1801) supported by the Scientific Research Foundation of Tianjin University of Technology and Education,China
文摘The microstructural evolution, mechanical properties and fracture mechanism of a Ti.5Al.5Mo.5V.3Cr.1Zr (Ti-55531) alloy after solution (760.820℃) plus aging (580.640℃) treatments were investigated. The results show that the volume fraction of the primary α(αp) phase decreases with the increase of solution temperature, and the length of the secondary α phase (αs) decreases while its width increases with the increase of aging temperature. Yield and tensile strengths decrease with the increase of solution temperature, while increase with the increase of aging temperature. A good balance of tensile strength and ductility of the alloy is obtained under solution of 800℃ for 2 h plus aging of 640℃ for 8 h, in which the tensile strength is 1434 MPa and the elongation is 7.7%. The coarsening αs phase makes crack propagation paths deflected and tortuous, which increases the crack propagation resistance and improves the ductility and fracture toughness.
文摘Ti-6AI-4V, among the Ti alloys, is the most widely used. In the present work, the behavior of Ti-6AI-4V alloy has been investigated by the uniaxial hot isothermal compression tests and a series of dilatometric experiments were also carried out to determine the transformation temperatures at different cooling rates. Specimens for hot compression tests were homogenized at 1050℃ for 10 min and then quickly cooled to different straining temperatures from 1050 to 850℃. Cooling rates were chosen fast enough to prevent high temperature transformation during cooling. Compression tests were conducted at temperatures from 1050 to 850℃ in steps of 50℃ at constant true strain rates of 10-3 or 10-2 s-1. The apparent activation energy for compression in two-phase region was calculated 420 kJ·mol-1. Partial globularization of a phase was observed in the specimen deformed at low strain rates and at temperatures near the transformation zone and annealed after deformation.
文摘The influence of different lubricants on the deformation behaviour of IN 718 alloy was studied. The results show that, with the improvement of lubrication condition, the deformation of the alloy tends to be homogeneous, and the resistance of deformation decreases. Consequently, FR 2 glass lubricant is considered to be an ideal choice when the relationship between stress and strain of IN 718 alloy is measured by means of hot compression experiment.
基金supported by the National Natural Science Foundation of China under grant No. 30973354
文摘The purpose of this study was to test the hypothesis that the combination of micro-arc oxidation and alkali heatment （MAH） would improve the cytocompatibility of a newly designed Ti-24Nb-4Zr-8Sn alloy. In this study, commercially pure titanium （cp Ti） and Ti-24Nb-4Zr-8Sn were used. Surface modification of Ti-24Nb- 4Zr-8Sn by a two-step treatment of micro-arc oxidation （MAO） and alkali heatment was reported. Surface characterizations were performed by scanning electron microscopy （SEM）, thin film X-ray diffraction （TF-XRD） and X-ray photoelectron spectroscopy （XPS）. The MAH layer consisted of finer crystals and possessed a higher degree of crystallity and stability than the MAO layer. A biocompatibility study on treated and untreated Ti- 24Nb-4Zr-8Sn in comparison with cp Ti was carried out to investigate the effect of the different surfaces on the bone integration property in vitro. The cellular assays revealed that the MAO and MAH layer favored the initial adhesion of MC3T3-E1 cells and that the growth rate of MC3T3-E1 cells on MAH layer was significantly higher than that on the conventional MAO-treated layer after 3-day and 5-day incubation, demonstrating the greater potential of the hybrid treatment of micro-arc oxidation followed with alkali heatment as a novel surface modification method for implanting materials.
