SAW sensors using five different types of polymer to detect of chemical agents(DMMP,CH_3CN,CH_2Cl_2,DCP) have been fabricated and its gas response characteristics were extensively investigated.The polymers used as the...SAW sensors using five different types of polymer to detect of chemical agents(DMMP,CH_3CN,CH_2Cl_2,DCP) have been fabricated and its gas response characteristics were extensively investigated.The polymers used as the sensing material are polyisobutylene(PIB),polyepichlorohydrin(PECH),polydimethylsiloxane(PDMS),polyisoprene(PIP)and polybutadiene(PBD).Their thin films were coated on quartz substrate by spin coating technique.Three types of simulants gases,dimethylmethylphosphonate(DMMP),acetonitrile(CH_3CN)and dichloromethane(CH_2Cl_2),dichloropentane(DCP)were used as target gases,instead of the real nerve,blood,choking and vesicant agents.After spin coating of PIB and PECH,the substrates were heated to 65℃with N_2 flow for 1 h to remove the cyclohexane and ethylacetate which was used as solvent. PDMS was heated to 75℃with N_2 flow for 2 h to remove the ethylacetate which was used as solvent.PBD and PIP on the substrate were heated to 60℃with N_2 flow for 1 h to remove the benzen which was used as solvent.The sensing characteristics of the SAW sensors were measured by using E-5061A network analyzer.展开更多
In the present research, the influence of chromium enrichment by surface treatment on corrosion resistance of type 316L stainless steel in body environment was investigated. For this study, weight loss test during 18 ...In the present research, the influence of chromium enrichment by surface treatment on corrosion resistance of type 316L stainless steel in body environment was investigated. For this study, weight loss test during 18 months, cyclic and liner polarization tests before and after surface treatment and metallography by electron and light microscopy were used to evaluate the effectiveness of the proposed method. In addition, X-ray photoelectron spectroscopy （XPS） method was used to determine the chromium concentration in the surface layer after surface treatment. Results show that the surface treatment has improved corrosion resistance of the type 316L stainless steel in body environment.展开更多
Equal channel angular pressing （ECAP） is an attractive process method to produce bulk uhra-fine grained materials. There are many experiment evidences showing that the nature of the microstructural evolution in mult...Equal channel angular pressing （ECAP） is an attractive process method to produce bulk uhra-fine grained materials. There are many experiment evidences showing that the nature of the microstructural evolution in multi-pass ECAP depends on process routes. Isothermal three dimensional FEM simulations for muhi-pass ECAP were performed using DEFORM3D finite element code. The material model of 6061A1-T6 was employed. Flow nets, effective strain distribution in the workpiece and loads during multi-pass ECAP using different routes were analysed respectively, The simulations show process routes influence material flow and effective strain distri- bution in the workpiece obviously but have few influence on loads.展开更多
The Impact toughness and fracture toughness of Austempered Ductile Iron (ADI) are described. The notched and un-notched Charpy impact toughness of ADI at room temperature are somewhat lower than that of steel castings...The Impact toughness and fracture toughness of Austempered Ductile Iron (ADI) are described. The notched and un-notched Charpy impact toughness of ADI at room temperature are somewhat lower than that of steel castings or forged steel pieces, however, they are approximately three times higher than that of normal pearlitic ductile iron. The impact toughness of ADI decreases with decreasing temperature; but at-40℃ it still maintains about 70% of the value at room temperature. The properties of fracture toughness are important in safety design and failure analysis. In this study all fracture toughness data of ADI are higher than that of conventional ductile iron, and are equivalent to or better than that of steel castings or forged steel pieces with the tensile strength equivalent to ADI.展开更多
Theoretical analyses show that the variation of wall thickness is in direct proportion to outer-diameter, inter-diameter, and (1+R_s)^(1/2) (Rs is sectional increase ratio of tube), the theoretical calculated results ...Theoretical analyses show that the variation of wall thickness is in direct proportion to outer-diameter, inter-diameter, and (1+R_s)^(1/2) (Rs is sectional increase ratio of tube), the theoretical calculated results of wall thickness during tube dieless upsetting are very approximate to the experimental one. As the width of deformation field increases, both the variation of wall thickness and the derivative of wall thickness variation to width of deformation field (to/tf) reduce.展开更多
An Al62.5Cu25Fe12.5 quasi-crystalline alloy was prepared by are melting. X-ray diffraction and scanning electron microscopy were used to study the microstructure of the quasi-crystalline alloy. Isothermal weight gain ...An Al62.5Cu25Fe12.5 quasi-crystalline alloy was prepared by are melting. X-ray diffraction and scanning electron microscopy were used to study the microstructure of the quasi-crystalline alloy. Isothermal weight gain of the Al-Cu-Fe quasi-crystal at elevated temperature in dry air was measured by means of a thermal balance and the oxidation behavior was evaluated by oxidation kinetic curves, from which it was deduced that the quasi-crystal exhibits good oxidation resistance. The surface morphologies of the Al-Cu-Fe quasi-crystal after isothermal oxidation at 700°C and 800°C for different times were observed. The oxidation resistance of quasi-crystalline powder and normal crystalline powder in the Al-Cu-Fe system was also quantitatively compared in quantity.展开更多
Lattice stability of Be is estimated,and interaction parameters for the liquids in the Al-Be and Be-Si systems are obtained using phase dia- gram data from literatures.Using the obtained parameters and the lattice sta...Lattice stability of Be is estimated,and interaction parameters for the liquids in the Al-Be and Be-Si systems are obtained using phase dia- gram data from literatures.Using the obtained parameters and the lattice stabilities of Al and Si given in the literatures,the Al-Be and Be-Si phase diagrams are calculated.By means of Kohler's for- mula the Gibbs energy for the liquid phase in the Al-Be-Si ternary system is extrapolated.The calcu- lation shows that no excess ternary term is necessa- ry for the thermodynamic description of the system. The liquidus projection,isothermal section at 1273 K,as well as vertical sections at 94 and 88 wt-% Al and 2 wt-% Be are calculated.The calcu- lated results are in reasonable agreement with the experimental data available.展开更多
1.IntroductionSo far there are few people who studythe relationship between the criticalhydrogen concentration and the stress forhvdrogen induced cracking (CCHIC)quantitatively.Several researchers have cal-culated the...1.IntroductionSo far there are few people who studythe relationship between the criticalhydrogen concentration and the stress forhvdrogen induced cracking (CCHIC)quantitatively.Several researchers have cal-culated the CCHIC of steels under no stressby means of H permeation method,but no展开更多
1.IntroductionZirconia doped with MgO,CaO,YO,and other rare earth oxides is a re-markable material due to its technologicalimportance,basic scientific interest as wellas superior synthetic properties[1].In orderto imp...1.IntroductionZirconia doped with MgO,CaO,YO,and other rare earth oxides is a re-markable material due to its technologicalimportance,basic scientific interest as wellas superior synthetic properties[1].In orderto improve the properties of the material,in-展开更多
Modification of the carbide characteristics through the grain boundary serration is investigated, using an AISI 316 and 304 stainless steels. In both steels, triangular carbides were observed at straight grain boundar...Modification of the carbide characteristics through the grain boundary serration is investigated, using an AISI 316 and 304 stainless steels. In both steels, triangular carbides were observed at straight grain boundaries while planar carbides were observed at the serrated grain boundaries. The serrated grain boundary energy is observed to be much lower than that of the straight one. Therefore, the carbide morphology is found to be changed from triangular to planar along the serrated boundary to reduce the interfacial energy between the carbide and the matrix. The creep-fatigue properties of these steels at 873K have been investigated. The creep-fatigue life of the sample with planar carbide at the serrated grain boundary was found to be much longer than that with triangular carbide at the straight one. These results imply that the planar carbides with lower interfacial energy have higher cavitation resistance, resulting in the retardation of cavity nucleation and growth to increase creep-fatigue life.展开更多
Using the calculation of thermodynamic equilibria in multicomponent systems,two ternary phase diagrams,Ni-Cr-Mo and Ni-Cr-Co,have been calculated by optimizing the Gibbs free ener- gies with respect to phase diagrams ...Using the calculation of thermodynamic equilibria in multicomponent systems,two ternary phase diagrams,Ni-Cr-Mo and Ni-Cr-Co,have been calculated by optimizing the Gibbs free ener- gies with respect to phase diagrams and thermodynamic data.On the basis of this calcula- tion,the occurrence of σ-phase in the residual solid solution of commercial Ni-base superalloys, IN-713C and U-700,has been predicted.The re- sults show that the calculation of phase equilibria is successful in the prediction of the occurrence of the σ-phase.展开更多
1.IntroductionMechanical alloying is one of the effec-tive methods to prepare amorphous alloys[1].This method was first used by Koch etal.to prepare the Ni;Nb;amorphous alloy[2].Since then many other amorphousbinary a...1.IntroductionMechanical alloying is one of the effec-tive methods to prepare amorphous alloys[1].This method was first used by Koch etal.to prepare the Ni;Nb;amorphous alloy[2].Since then many other amorphousbinary alloys have been prepared by the展开更多
1.IntroductionThe influence of substitution of variouselements for Fe on the magnetic propertiesof the NdFeBalloy has been investi-gated by several authors,among which theAl substitution can increase the coercivity[1]...1.IntroductionThe influence of substitution of variouselements for Fe on the magnetic propertiesof the NdFeBalloy has been investi-gated by several authors,among which theAl substitution can increase the coercivity[1]and the addition of both Co and Al has beenproved to have a positive effect on im-proving both the coercivity and other per-展开更多
The magnetic properties and anisotropy of amor- phous(Fe_(80)Ni_(20))_(78)Si_xB_(22-x).alloys have been investigated systematically.The maximum permeability,coercive force and remanence have been determined for as-pre...The magnetic properties and anisotropy of amor- phous(Fe_(80)Ni_(20))_(78)Si_xB_(22-x).alloys have been investigated systematically.The maximum permeability,coercive force and remanence have been determined for as-prepared and annealed samples,The results on the technical magnetic properties of this alloy system have been discussed and compared with Masumoto's.展开更多
The disaccommodation of magnetic per- meability,specific magnetization and linear magnetostriction of amorphous(Fe_xNi_(1-x))_(76)- Si_8B_(16)alloys were measured.It was found that the disaccommodation obtained at low...The disaccommodation of magnetic per- meability,specific magnetization and linear magnetostriction of amorphous(Fe_xNi_(1-x))_(76)- Si_8B_(16)alloys were measured.It was found that the disaccommodation obtained at lower temperature is a monotonically decreasing function of Fe content, however,a peak is observed at higher temperature. The experimental results are discussed on the basis of magnetostrictive interaction and atomic directional ordering.展开更多
文摘SAW sensors using five different types of polymer to detect of chemical agents(DMMP,CH_3CN,CH_2Cl_2,DCP) have been fabricated and its gas response characteristics were extensively investigated.The polymers used as the sensing material are polyisobutylene(PIB),polyepichlorohydrin(PECH),polydimethylsiloxane(PDMS),polyisoprene(PIP)and polybutadiene(PBD).Their thin films were coated on quartz substrate by spin coating technique.Three types of simulants gases,dimethylmethylphosphonate(DMMP),acetonitrile(CH_3CN)and dichloromethane(CH_2Cl_2),dichloropentane(DCP)were used as target gases,instead of the real nerve,blood,choking and vesicant agents.After spin coating of PIB and PECH,the substrates were heated to 65℃with N_2 flow for 1 h to remove the cyclohexane and ethylacetate which was used as solvent. PDMS was heated to 75℃with N_2 flow for 2 h to remove the ethylacetate which was used as solvent.PBD and PIP on the substrate were heated to 60℃with N_2 flow for 1 h to remove the benzen which was used as solvent.The sensing characteristics of the SAW sensors were measured by using E-5061A network analyzer.
文摘In the present research, the influence of chromium enrichment by surface treatment on corrosion resistance of type 316L stainless steel in body environment was investigated. For this study, weight loss test during 18 months, cyclic and liner polarization tests before and after surface treatment and metallography by electron and light microscopy were used to evaluate the effectiveness of the proposed method. In addition, X-ray photoelectron spectroscopy （XPS） method was used to determine the chromium concentration in the surface layer after surface treatment. Results show that the surface treatment has improved corrosion resistance of the type 316L stainless steel in body environment.
基金The National Natural Science Foundation of China(No50474028)
文摘Equal channel angular pressing （ECAP） is an attractive process method to produce bulk uhra-fine grained materials. There are many experiment evidences showing that the nature of the microstructural evolution in multi-pass ECAP depends on process routes. Isothermal three dimensional FEM simulations for muhi-pass ECAP were performed using DEFORM3D finite element code. The material model of 6061A1-T6 was employed. Flow nets, effective strain distribution in the workpiece and loads during multi-pass ECAP using different routes were analysed respectively, The simulations show process routes influence material flow and effective strain distri- bution in the workpiece obviously but have few influence on loads.
文摘The Impact toughness and fracture toughness of Austempered Ductile Iron (ADI) are described. The notched and un-notched Charpy impact toughness of ADI at room temperature are somewhat lower than that of steel castings or forged steel pieces, however, they are approximately three times higher than that of normal pearlitic ductile iron. The impact toughness of ADI decreases with decreasing temperature; but at-40℃ it still maintains about 70% of the value at room temperature. The properties of fracture toughness are important in safety design and failure analysis. In this study all fracture toughness data of ADI are higher than that of conventional ductile iron, and are equivalent to or better than that of steel castings or forged steel pieces with the tensile strength equivalent to ADI.
基金Sponsored by Ministry of Education of China and Natural Science Foundation of Liaoning Province
文摘Theoretical analyses show that the variation of wall thickness is in direct proportion to outer-diameter, inter-diameter, and (1+R_s)^(1/2) (Rs is sectional increase ratio of tube), the theoretical calculated results of wall thickness during tube dieless upsetting are very approximate to the experimental one. As the width of deformation field increases, both the variation of wall thickness and the derivative of wall thickness variation to width of deformation field (to/tf) reduce.
文摘An Al62.5Cu25Fe12.5 quasi-crystalline alloy was prepared by are melting. X-ray diffraction and scanning electron microscopy were used to study the microstructure of the quasi-crystalline alloy. Isothermal weight gain of the Al-Cu-Fe quasi-crystal at elevated temperature in dry air was measured by means of a thermal balance and the oxidation behavior was evaluated by oxidation kinetic curves, from which it was deduced that the quasi-crystal exhibits good oxidation resistance. The surface morphologies of the Al-Cu-Fe quasi-crystal after isothermal oxidation at 700°C and 800°C for different times were observed. The oxidation resistance of quasi-crystalline powder and normal crystalline powder in the Al-Cu-Fe system was also quantitatively compared in quantity.
基金This work is financially supported by the FlandersChina bilateral project (BIL 99/10) and the Science and Technology Committee of Shanghai Municipality. The authors are thankful to Prof. H.L.Lukas, offering the new version of the Lukas Program.
文摘Lattice stability of Be is estimated,and interaction parameters for the liquids in the Al-Be and Be-Si systems are obtained using phase dia- gram data from literatures.Using the obtained parameters and the lattice stabilities of Al and Si given in the literatures,the Al-Be and Be-Si phase diagrams are calculated.By means of Kohler's for- mula the Gibbs energy for the liquid phase in the Al-Be-Si ternary system is extrapolated.The calcu- lation shows that no excess ternary term is necessa- ry for the thermodynamic description of the system. The liquidus projection,isothermal section at 1273 K,as well as vertical sections at 94 and 88 wt-% Al and 2 wt-% Be are calculated.The calcu- lated results are in reasonable agreement with the experimental data available.
文摘1.IntroductionSo far there are few people who studythe relationship between the criticalhydrogen concentration and the stress forhvdrogen induced cracking (CCHIC)quantitatively.Several researchers have cal-culated the CCHIC of steels under no stressby means of H permeation method,but no
文摘1.IntroductionZirconia doped with MgO,CaO,YO,and other rare earth oxides is a re-markable material due to its technologicalimportance,basic scientific interest as wellas superior synthetic properties[1].In orderto improve the properties of the material,in-
文摘Modification of the carbide characteristics through the grain boundary serration is investigated, using an AISI 316 and 304 stainless steels. In both steels, triangular carbides were observed at straight grain boundaries while planar carbides were observed at the serrated grain boundaries. The serrated grain boundary energy is observed to be much lower than that of the straight one. Therefore, the carbide morphology is found to be changed from triangular to planar along the serrated boundary to reduce the interfacial energy between the carbide and the matrix. The creep-fatigue properties of these steels at 873K have been investigated. The creep-fatigue life of the sample with planar carbide at the serrated grain boundary was found to be much longer than that with triangular carbide at the straight one. These results imply that the planar carbides with lower interfacial energy have higher cavitation resistance, resulting in the retardation of cavity nucleation and growth to increase creep-fatigue life.
文摘Using the calculation of thermodynamic equilibria in multicomponent systems,two ternary phase diagrams,Ni-Cr-Mo and Ni-Cr-Co,have been calculated by optimizing the Gibbs free ener- gies with respect to phase diagrams and thermodynamic data.On the basis of this calcula- tion,the occurrence of σ-phase in the residual solid solution of commercial Ni-base superalloys, IN-713C and U-700,has been predicted.The re- sults show that the calculation of phase equilibria is successful in the prediction of the occurrence of the σ-phase.
文摘1.IntroductionMechanical alloying is one of the effec-tive methods to prepare amorphous alloys[1].This method was first used by Koch etal.to prepare the Ni;Nb;amorphous alloy[2].Since then many other amorphousbinary alloys have been prepared by the
文摘1.IntroductionThe influence of substitution of variouselements for Fe on the magnetic propertiesof the NdFeBalloy has been investi-gated by several authors,among which theAl substitution can increase the coercivity[1]and the addition of both Co and Al has beenproved to have a positive effect on im-proving both the coercivity and other per-
文摘The magnetic properties and anisotropy of amor- phous(Fe_(80)Ni_(20))_(78)Si_xB_(22-x).alloys have been investigated systematically.The maximum permeability,coercive force and remanence have been determined for as-prepared and annealed samples,The results on the technical magnetic properties of this alloy system have been discussed and compared with Masumoto's.
文摘The disaccommodation of magnetic per- meability,specific magnetization and linear magnetostriction of amorphous(Fe_xNi_(1-x))_(76)- Si_8B_(16)alloys were measured.It was found that the disaccommodation obtained at lower temperature is a monotonically decreasing function of Fe content, however,a peak is observed at higher temperature. The experimental results are discussed on the basis of magnetostrictive interaction and atomic directional ordering.
