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1Research Progress and Application Perspectives of 4D Printing
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2Effect of Rare Earth Y on Microstructure and Properties of Sn-58Bi Solder Alloy
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3Research Progress in Preparation and Crystallization Technologies of Amorphous ITO Film
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4Effect of Mo content on Microstructure and Mechanical Properties of IN718 Alloy
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5Progress on Self-Healing and Structure-Wave Absorbing Integration of Silicon Carbide Ceramic Matrix Composites
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6Research Progress of Laser Shock Treatment in the Field of Material Forming
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7Research Progress in Cemented Carbide with Co-Ni-Al Composite Binder Phase
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8Research Process in Plasma Spray Physical Vapor Deposited Thermal Barrier Coatings
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92018-04-Catalog
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10Research Progress of Metal-Intermetallic Laminated Composites
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11Additive Manufacture of Metamaterials: a Review
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12Novel Ceramic Materials for Thermal Barrier Coatings
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13Research Progress on Preforms of C/C Composites
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14Effect of Hot Deformation on PPB Precipitations and Microstructure in P/M Superalloy FGH96
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15Research Progress on Deployable Structures of Shape Memory Polymer Composites
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16Microstructure and Mechanical Properties of ZrC-TaC Ceramic Prepared by Hot Pressing Sintering
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1Effect of Filler Systems on Properties of Fluororubber Vulcanized by Peroxide
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2First-principle Calculations of Mechanical Properties of Al2Cu, Al2CuMg and MgZn2 Intermetallics in High Strength Aluminum Alloys
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3Research Process in Plasma Spray Physical Vapor Deposited Thermal Barrier Coatings
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4Effect of Rare Earth Y on Microstructure and Properties of Sn-58Bi Solder Alloy
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5Current Study and Novel Ideas on Magnesium Matrix Composites
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62018-02-Catalog
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7High Temperature Titanium Alloys：Status and Perspective
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8Progress in Amorphous Transparent Conducting Oxide Thin Films
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9Research and Application Progress of Silicone Rubber Materials in Aviation
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10Failure and Protection of Thermal Barrier Coating under CMAS Attack
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11Additive Manufacture of Metamaterials: a Review
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12Research Progress on Deployable Structures of Shape Memory Polymer Composites
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13Research Progress in Preparation and Crystallization Technologies of Amorphous ITO Film
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14Research Progress in Cemented Carbide with Co-Ni-Al Composite Binder Phase
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15Progress on Self-Healing and Structure-Wave Absorbing Integration of Silicon Carbide Ceramic Matrix Composites
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16Novel Ceramic Materials for Thermal Barrier Coatings
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Available online
, doi: 10.11868/j.issn.1005-5053.2018.000055
Abstract:
As the laminate is essentially bonded together to form the individual laminate by the matrix, any delamination of the laminate must be initiated from a matrix failure. Based on this viewpoint, the initiation of laminate delamination was predicted through analyzing the stresses of the matrix. A three-dimensional finite element method is used to calculate the stress field of a symmetrically laminated plate under an axial load. A convergence study was performed and an average stress method was proposed to solve the singularity problem. Then the internal stresses in the fiber and matrix are determined in terms of the Bridging Micromechanics Model. Finally, a Mohr criterion was used to detect the failure of matrix. T800/914 Angle-plied laminates are considered. The results show that this approach is able to correlate reasonably with the available experimental data.
As the laminate is essentially bonded together to form the individual laminate by the matrix, any delamination of the laminate must be initiated from a matrix failure. Based on this viewpoint, the initiation of laminate delamination was predicted through analyzing the stresses of the matrix. A three-dimensional finite element method is used to calculate the stress field of a symmetrically laminated plate under an axial load. A convergence study was performed and an average stress method was proposed to solve the singularity problem. Then the internal stresses in the fiber and matrix are determined in terms of the Bridging Micromechanics Model. Finally, a Mohr criterion was used to detect the failure of matrix. T800/914 Angle-plied laminates are considered. The results show that this approach is able to correlate reasonably with the available experimental data.
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Available online
, doi: 10.11868/j.issn.1005-5053.2018.000085
Abstract:
As one kind of near alpha titanium alloys with excellent mechanical properties, Ti6242 alloy always shows the" dwell fatigue”characteristic, which is similar to other near α or α+β titanium alloys, especially at near room temperature. In this study, the low cycle fatigue and dwell fatigue tests under high load were designed according to the law of dwell fatigue sensitivity rising with the increase of test load. Combining with microstructure observation, mechanical property tests and failure fracture analysis, the relationship between the microstructure and the fracture behavior under high load low cycle fatigue and dwell fatigue tests was analyzed systematically. By summarizing the characteristics of failure fracture under room temperature tensile, high load low cycle fatigue test and high load dwell fatigue test, also comparing the dwell fatigue sensitivity of the Ti6242 alloy in this study with other Ti6242 alloys and other titanium alloys under different loading conditions, it is proved that increasing the fatigue load is a feasible way to characterize the dwell fatigue sensitivity of Ti6242 alloy.
As one kind of near alpha titanium alloys with excellent mechanical properties, Ti6242 alloy always shows the" dwell fatigue”characteristic, which is similar to other near α or α+β titanium alloys, especially at near room temperature. In this study, the low cycle fatigue and dwell fatigue tests under high load were designed according to the law of dwell fatigue sensitivity rising with the increase of test load. Combining with microstructure observation, mechanical property tests and failure fracture analysis, the relationship between the microstructure and the fracture behavior under high load low cycle fatigue and dwell fatigue tests was analyzed systematically. By summarizing the characteristics of failure fracture under room temperature tensile, high load low cycle fatigue test and high load dwell fatigue test, also comparing the dwell fatigue sensitivity of the Ti6242 alloy in this study with other Ti6242 alloys and other titanium alloys under different loading conditions, it is proved that increasing the fatigue load is a feasible way to characterize the dwell fatigue sensitivity of Ti6242 alloy.
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Available online
, doi: 10.11868/j.issn.1005-5053.2014.3.002
Abstract:
To analyze the relationship between composition, microstructure and mechanical properties of TA15 titanium alloys, the quasi-static tensile properties and dynamic properties at room temperature of four TA15 titanium alloys were studied by the electronic universal tensile testing machine and split hopkinson pressure bar (SHPB). The results reveal that the Zr content has little effect on the tensile strength at room temperature, moreover, with the increasing content of main alloy elements Al, V and Mo, the content of primary α phase decreases and the lamella width of secondary α phase is thinner which provide higher strength and lower plasticity. Slight changes in alloy composition have little effect on dynamic mechanical properties within the critical strain rate range. Increasing the content of main alloy elements Al, Zr, V and Mo is beneficial to improve the critical strain rate at which the alloy has excellent dynamic mechanical properties. For equiaxed TA15 titanium alloys obtained under air cooling condition, the smaller volume fraction of primary α phase and thinner lamella of secondary α phase can improve the tensile strength, critical strain rate and dynamic mechanical properties at room temperature.
To analyze the relationship between composition, microstructure and mechanical properties of TA15 titanium alloys, the quasi-static tensile properties and dynamic properties at room temperature of four TA15 titanium alloys were studied by the electronic universal tensile testing machine and split hopkinson pressure bar (SHPB). The results reveal that the Zr content has little effect on the tensile strength at room temperature, moreover, with the increasing content of main alloy elements Al, V and Mo, the content of primary α phase decreases and the lamella width of secondary α phase is thinner which provide higher strength and lower plasticity. Slight changes in alloy composition have little effect on dynamic mechanical properties within the critical strain rate range. Increasing the content of main alloy elements Al, Zr, V and Mo is beneficial to improve the critical strain rate at which the alloy has excellent dynamic mechanical properties. For equiaxed TA15 titanium alloys obtained under air cooling condition, the smaller volume fraction of primary α phase and thinner lamella of secondary α phase can improve the tensile strength, critical strain rate and dynamic mechanical properties at room temperature.
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Available online
, doi: 10.11868/j.issn.1005-5053.2017.00035
Abstract:
The governing differential equations of Ceramic-based functionally graded material (FGM) circular plate with linear variable thickness along the radius in thermal environment were established. The thermal post-buckling behaviors of variable thickness FGM circular plate made of Ceramic and Metal in thermal environment were proposed by shooting method technique. The equilibrium paths of the FGM variable thickness circular plate subjected to uniform temperature rise and heat conduction are presented. The influence of ceramic gradient index and thickness variation coefficient on post buckling behavior is discussed. The numerical results show that the thermal critical load of non-uniform temperature rise is less than the one under uniform load. The change of radial thickness does not affect the thermal critical load value, but that will affect the post-buckling equilibrium path. The center deflection increases with the increase of variable thickness coefficient.
The governing differential equations of Ceramic-based functionally graded material (FGM) circular plate with linear variable thickness along the radius in thermal environment were established. The thermal post-buckling behaviors of variable thickness FGM circular plate made of Ceramic and Metal in thermal environment were proposed by shooting method technique. The equilibrium paths of the FGM variable thickness circular plate subjected to uniform temperature rise and heat conduction are presented. The influence of ceramic gradient index and thickness variation coefficient on post buckling behavior is discussed. The numerical results show that the thermal critical load of non-uniform temperature rise is less than the one under uniform load. The change of radial thickness does not affect the thermal critical load value, but that will affect the post-buckling equilibrium path. The center deflection increases with the increase of variable thickness coefficient.
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2018, 38(6): 1 -10
doi: 10.11868/j.issn.1005-5053.2018.000081
Abstract:
Laser shock treatment is a kind of advanced surface strengthening technology for metallic materials, and its remarkable strengthening effect has been verified and universally accepted in many different metallic materials. In order to prevent the influence of laser shock on the shape size of precision parts or make use of the technology to introduce plastic deformation of metallic materials, it is necessary to study the deformation criterion of materials under laser shock. In this paper, the deformation law of different materials treated by laser shock is analyzed, and the limitation of laser shock in deformation phenomenon is explained based on the deformation mechanism of stress gradient and impact bending, the necessity of basic research on material deformation caused by laser shock is proposed. The effect of many factors such as laser parameters and impact modes, constraint modes on the laser shock-induced deformation is summarized, and it is proved that the adjustment and optimization of multiple parameters play an important role in controlling laser shock-induced deformation degree. Moreover, the advantages of numerical simulation method in the study of laser shock-induced deformation are analyzed in this paper, and at the same time,the urgency of establishing a material constitutive model adapting to high strain rate deformation and perfecting the simulation of laser plasma formation process is put forward. The development of laser shock deformation law in advanced manufacturing industry is prospected through the introduction of the sizing technology of laser shock, and the research directions of the deformation calibration based on laser shock and the on-line monitoring of deformation degree are presented.
Laser shock treatment is a kind of advanced surface strengthening technology for metallic materials, and its remarkable strengthening effect has been verified and universally accepted in many different metallic materials. In order to prevent the influence of laser shock on the shape size of precision parts or make use of the technology to introduce plastic deformation of metallic materials, it is necessary to study the deformation criterion of materials under laser shock. In this paper, the deformation law of different materials treated by laser shock is analyzed, and the limitation of laser shock in deformation phenomenon is explained based on the deformation mechanism of stress gradient and impact bending, the necessity of basic research on material deformation caused by laser shock is proposed. The effect of many factors such as laser parameters and impact modes, constraint modes on the laser shock-induced deformation is summarized, and it is proved that the adjustment and optimization of multiple parameters play an important role in controlling laser shock-induced deformation degree. Moreover, the advantages of numerical simulation method in the study of laser shock-induced deformation are analyzed in this paper, and at the same time,the urgency of establishing a material constitutive model adapting to high strain rate deformation and perfecting the simulation of laser plasma formation process is put forward. The development of laser shock deformation law in advanced manufacturing industry is prospected through the introduction of the sizing technology of laser shock, and the research directions of the deformation calibration based on laser shock and the on-line monitoring of deformation degree are presented.
2018, 38(6): 11 -18
doi: 10.11868/j.issn.1005-5053.2017.000197
Abstract:
CdTe photoelectric material with one-dimensional nanostructure and Bi2Te3 thermoelectric material were successively grown on FTO substrate by magnetron sputtering method for forming FTO/CdTe/Bi2Te3 heterojunction thin film. Whereafter, a power device was prepared by processing Ag electrode. The property of the device with light and heat synergy response was characterized by the V-t curve, which was collected through the circuit and optical path design. With the time difference between light and heat response, the curve of voltage-time was collected under the different light source, electrode contact point and light illumination direction. Meanwhile, the phenomenon of light and heat synergy response was identified with the illumination intensity of halogen and xenon light changeable. The results show that the synergy of photoelectric material and thermoelectric material in a single cell of CdTe/Bi2Te3 heterojunction can realize the light and heat synergy response, and it is anticipated to harvest solar energy from a wider solar spectrum.
CdTe photoelectric material with one-dimensional nanostructure and Bi2Te3 thermoelectric material were successively grown on FTO substrate by magnetron sputtering method for forming FTO/CdTe/Bi2Te3 heterojunction thin film. Whereafter, a power device was prepared by processing Ag electrode. The property of the device with light and heat synergy response was characterized by the V-t curve, which was collected through the circuit and optical path design. With the time difference between light and heat response, the curve of voltage-time was collected under the different light source, electrode contact point and light illumination direction. Meanwhile, the phenomenon of light and heat synergy response was identified with the illumination intensity of halogen and xenon light changeable. The results show that the synergy of photoelectric material and thermoelectric material in a single cell of CdTe/Bi2Te3 heterojunction can realize the light and heat synergy response, and it is anticipated to harvest solar energy from a wider solar spectrum.
2018, 38(6): 19 -28
doi: 10.11868/j.issn.1005-5053.2018.000071
Abstract:
Effects of alloying elements on the equilibrium precipitated phases, incipient and final melting temperature of Mar-M247 superalloy were studied through thermodynamic calculation. The results show that the main phases are γ' precipitates, MC, M6C, M23C6 carbides, μ phases, MB2 and M3B2 borides. Hf and Ta segregate more seriously mostly during solidification process. Around the composition range, Cr, Mo, Ti and Hf influence the initial melting temperature mostly. Precipitation temperature and precipitation amount of carbides increase linearly with the increase of the C content. Furthermore, Hf, Ti and Ta are contributed to the precipitation of MC carbides, Cr improves the precipitation of M23C6 and W and Mo are beneficial to the precipitation of M6C. The precipitation of μ phase is mainly influenced by Mo and W, the precipitation temperature and mass fraction of μ phase increase as the content of Mo and W increase. The precipitation behavior of γ' phase is affected by Al, Ti and Ta contents, and their effects decrease in turn.
Effects of alloying elements on the equilibrium precipitated phases, incipient and final melting temperature of Mar-M247 superalloy were studied through thermodynamic calculation. The results show that the main phases are γ' precipitates, MC, M6C, M23C6 carbides, μ phases, MB2 and M3B2 borides. Hf and Ta segregate more seriously mostly during solidification process. Around the composition range, Cr, Mo, Ti and Hf influence the initial melting temperature mostly. Precipitation temperature and precipitation amount of carbides increase linearly with the increase of the C content. Furthermore, Hf, Ti and Ta are contributed to the precipitation of MC carbides, Cr improves the precipitation of M23C6 and W and Mo are beneficial to the precipitation of M6C. The precipitation of μ phase is mainly influenced by Mo and W, the precipitation temperature and mass fraction of μ phase increase as the content of Mo and W increase. The precipitation behavior of γ' phase is affected by Al, Ti and Ta contents, and their effects decrease in turn.
2018, 38(6): 29 -35
doi: 10.11868/j.issn.1005-5053.2017.000187
Abstract:
Co-Cr-W alloy was prepared by powder metallurgy technology. The effect of heat treatment temperature on the microstructure and mechanical properties of the prepared alloy was investigated by SEM and EPMA, etc. The results show that the phases in Co-Cr-W alloy under the heat treatment condition of 1100 ℃ with holding time of 4 h and cooling without power is the same as before heat treatment. The matrix of alloy is composed of γ-Co with FCC structure, ε-Co with HCP structure, and the reinforced phases include M6C and M23C6 carbides. The matrix of Co-Cr-W alloy under the heat treatment condition of 1150-1250 ℃ × 4 h is composed of single γ-Co in FCC structure and reinforced phases include M6C carbides and M23C6 carbides. When the heat treatment temperature is increased from 1100 ℃ to 1200 ℃, the blocky M6C carbides and granular M23C6 carbides grow up, meanwhile ε-Co phases are reduced and then disappeared, alloy density is improved, and tensile strength is increased. However, when the heat treatment temperature is above 1200 ℃, the performance of Co-Cr-W alloy has no obvious change, and the prepared alloy under the heat treatment condition of 1200 ℃ × 4 h achieves the optimal property with the average hardness of 63.5HRC and tensile strength of 408 MPa.
Co-Cr-W alloy was prepared by powder metallurgy technology. The effect of heat treatment temperature on the microstructure and mechanical properties of the prepared alloy was investigated by SEM and EPMA, etc. The results show that the phases in Co-Cr-W alloy under the heat treatment condition of 1100 ℃ with holding time of 4 h and cooling without power is the same as before heat treatment. The matrix of alloy is composed of γ-Co with FCC structure, ε-Co with HCP structure, and the reinforced phases include M6C and M23C6 carbides. The matrix of Co-Cr-W alloy under the heat treatment condition of 1150-1250 ℃ × 4 h is composed of single γ-Co in FCC structure and reinforced phases include M6C carbides and M23C6 carbides. When the heat treatment temperature is increased from 1100 ℃ to 1200 ℃, the blocky M6C carbides and granular M23C6 carbides grow up, meanwhile ε-Co phases are reduced and then disappeared, alloy density is improved, and tensile strength is increased. However, when the heat treatment temperature is above 1200 ℃, the performance of Co-Cr-W alloy has no obvious change, and the prepared alloy under the heat treatment condition of 1200 ℃ × 4 h achieves the optimal property with the average hardness of 63.5HRC and tensile strength of 408 MPa.
2018, 38(6): 36 -42
doi: 10.11868/j.issn.1005-5053.2017.000049
Abstract:
Effects of current density, oxidation time and sealing on thermal control properties of anodic coatings of magnesium-lithium alloy were investigated. The microstructure, thermal control properties, adhesion properties, thickness, thermal cycling test and corrosion resistance were studied. The results indicate that high infrared emittance (εH) increases with the increase of current density and oxidation time, eventually stabilizes at around 0.85. Sealing has little effect on high infrared emittance (εH); variation of εH is in the range of less than 0.05. After 96 h neutral salt spray test, the coating shows good corrosion resistance.
Effects of current density, oxidation time and sealing on thermal control properties of anodic coatings of magnesium-lithium alloy were investigated. The microstructure, thermal control properties, adhesion properties, thickness, thermal cycling test and corrosion resistance were studied. The results indicate that high infrared emittance (εH) increases with the increase of current density and oxidation time, eventually stabilizes at around 0.85. Sealing has little effect on high infrared emittance (εH); variation of εH is in the range of less than 0.05. After 96 h neutral salt spray test, the coating shows good corrosion resistance.
2018, 38(6): 43 -49
doi: 10.11868/j.issn.1005-5053.2018.000009
Abstract:
Y-La was added into the second generation of nickel base single crystal superalloy and two kinds of alloy castings with Y-La content of 5.26 × 10–4%(mass fraction, ) Y + 6.05 × 10–4% La and 47.64 × 10–4% Y + 69.09 × 10–4% La were obtained after directional solidification. The effect of Y-La content on the interface reaction between alloy melts and Al2O3 based ceramics during directional solidification was investigated. The effect of alloy content on oxidation resistance of alloy at 1100 oC under cyclic oxidation was studied. The microstructure at the interface between alloy and mould, as well as the surface cross-section and fracture morphologies of the specimens, was characterized by means of scanning electron microscope (SME) with an energy-dispersive spectroscopy attachment. The phases of the oxides were identified by X-ray diffraction. The results show that the increase of Y-La content promotes the interfacial reaction, which makes the reaction layer thicker and more complex. The main reaction products are oxides containing Y and La. The addition of Y-La obviously improves the oxidation resistance of the alloy and reduces the exfoliation of the oxide film on the surface of the alloy. However, excessive Y-La will deteriorate the oxidation resistance of the alloy, accelerate the oxidation weight gain rate of the alloy. And the oxide film of the alloy surface has obvious traces of exfoliation, more holes and serious internal oxidation.
Y-La was added into the second generation of nickel base single crystal superalloy and two kinds of alloy castings with Y-La content of 5.26 × 10–4%(mass fraction, ) Y + 6.05 × 10–4% La and 47.64 × 10–4% Y + 69.09 × 10–4% La were obtained after directional solidification. The effect of Y-La content on the interface reaction between alloy melts and Al2O3 based ceramics during directional solidification was investigated. The effect of alloy content on oxidation resistance of alloy at 1100 oC under cyclic oxidation was studied. The microstructure at the interface between alloy and mould, as well as the surface cross-section and fracture morphologies of the specimens, was characterized by means of scanning electron microscope (SME) with an energy-dispersive spectroscopy attachment. The phases of the oxides were identified by X-ray diffraction. The results show that the increase of Y-La content promotes the interfacial reaction, which makes the reaction layer thicker and more complex. The main reaction products are oxides containing Y and La. The addition of Y-La obviously improves the oxidation resistance of the alloy and reduces the exfoliation of the oxide film on the surface of the alloy. However, excessive Y-La will deteriorate the oxidation resistance of the alloy, accelerate the oxidation weight gain rate of the alloy. And the oxide film of the alloy surface has obvious traces of exfoliation, more holes and serious internal oxidation.
2018, 38(6): 50 -56
doi: 10.11868/j.issn.1005-5053.2018.000062
Abstract:
Selective laser melting (SLM) was used to fabricate Hastelloy X alloy. The characteristics of grains and precipitates in Hastelloy X alloy processed by heat treatments (HT) and hot isostatic pressing (HIP) was analyzed. Furthermore, the tensile property of Hastelloy X alloys at ambient temperature and elevated temperature was investigated. Some grains exhibit columnar crystal morphology in vertically built samples, while the grains are equiaxial in horizontally built samples. The carbide phases with cubic structure are formed within grains and at grain boundaries simultaneously after a combination of HT and HIP. The horizontally built samples exhibits high tensile strength and low plasticity compared with the vertically built ones. Both of vertically built and horizontally built samples show predominantly ductile failure as characterized by dimpled microstructure. The tensile strength of Hastelloy X alloy at ambient temperature produced by SLM is 95% higher than that of hot forged alloy, while the tensile strength at 600℃ is about 85% of hot forged ones.
Selective laser melting (SLM) was used to fabricate Hastelloy X alloy. The characteristics of grains and precipitates in Hastelloy X alloy processed by heat treatments (HT) and hot isostatic pressing (HIP) was analyzed. Furthermore, the tensile property of Hastelloy X alloys at ambient temperature and elevated temperature was investigated. Some grains exhibit columnar crystal morphology in vertically built samples, while the grains are equiaxial in horizontally built samples. The carbide phases with cubic structure are formed within grains and at grain boundaries simultaneously after a combination of HT and HIP. The horizontally built samples exhibits high tensile strength and low plasticity compared with the vertically built ones. Both of vertically built and horizontally built samples show predominantly ductile failure as characterized by dimpled microstructure. The tensile strength of Hastelloy X alloy at ambient temperature produced by SLM is 95% higher than that of hot forged alloy, while the tensile strength at 600℃ is about 85% of hot forged ones.
2018, 38(6): 57 -63
doi: 10.11868/j.issn.1005-5053.2018.000043
Abstract:
Using BACE / PBEP polymer as matrix and superconducting carbon black (CB) as reinforcing material, the shape memory composites was prepared by compression molding. The effect of carbon black content on the shape memory properties and electro-induced efficiency of shape memory composites was studied. The results show that the shape memory composites can be completely recovered to its initial state under 180 V, when the shape fixation rate is 100%, CB content is 2.4%, and the conductive pathway is formed. With the increase of carbon black content, the deployable strength is also gradually increased, when the CB content is 2.6%, the maximum deployable strength reaches 0.05 MPa.
Using BACE / PBEP polymer as matrix and superconducting carbon black (CB) as reinforcing material, the shape memory composites was prepared by compression molding. The effect of carbon black content on the shape memory properties and electro-induced efficiency of shape memory composites was studied. The results show that the shape memory composites can be completely recovered to its initial state under 180 V, when the shape fixation rate is 100%, CB content is 2.4%, and the conductive pathway is formed. With the increase of carbon black content, the deployable strength is also gradually increased, when the CB content is 2.6%, the maximum deployable strength reaches 0.05 MPa.
Phase Morphology and Chemorheology during Curing of Polyethersulfone/Bismaleimide Multi-phase System
2018, 38(6): 64 -70
doi: 10.11868/j.issn.1005-5053.2018.000069
Abstract:
Curing characteristic of bismaleimide (BMI)/polyethersulfone (PES) multi-phase systems was studied by differential scanning calorimetry (DSC) using the non-isothermal method under different heating rates. The phase morphological evolution of BMI/PES-20 resin with the curing temperature and time was investigated by SEM. The chemorheology of BMI/PES was researched by rotational rheometer. Eventually, the relationship between phase separation and rheological properties was discussed. The results indicate that with the increase of the heating rate, the curing rate increases, and the curing characteristic temperatures of BMI/PES-25 systems shift toward higher temperature values but the curing enthalpy values are almost constant. With the increases of temperature, the viscosity keeps constant at low temperature in the curing temperature range of 110-150 ℃, and then increases rapidly. The temperature range, in which resin system maintains low viscosity, is widened with the increase of PES content. The viscosity of BMI/PES-25 displays a remarkable decrease in the curing temperature range of 180-200 ℃, as attributed to the phenomenon that the co-continuous structures convert to the phase inversion structures. The viscosity of BMI/PES-20 has no obvious change in the curing temperature range of 190-200 ℃, and increases rapidly above 200 ℃. The viscosities of BMI/PES-15, BMI/PES-10 and BMI/PES-5 resin systems increase rapidly above 180 ℃. SEM shows that these BMI/PES resins exhibit the ripening of phase structure during the temperature range of 180-200 ℃.
Curing characteristic of bismaleimide (BMI)/polyethersulfone (PES) multi-phase systems was studied by differential scanning calorimetry (DSC) using the non-isothermal method under different heating rates. The phase morphological evolution of BMI/PES-20 resin with the curing temperature and time was investigated by SEM. The chemorheology of BMI/PES was researched by rotational rheometer. Eventually, the relationship between phase separation and rheological properties was discussed. The results indicate that with the increase of the heating rate, the curing rate increases, and the curing characteristic temperatures of BMI/PES-25 systems shift toward higher temperature values but the curing enthalpy values are almost constant. With the increases of temperature, the viscosity keeps constant at low temperature in the curing temperature range of 110-150 ℃, and then increases rapidly. The temperature range, in which resin system maintains low viscosity, is widened with the increase of PES content. The viscosity of BMI/PES-25 displays a remarkable decrease in the curing temperature range of 180-200 ℃, as attributed to the phenomenon that the co-continuous structures convert to the phase inversion structures. The viscosity of BMI/PES-20 has no obvious change in the curing temperature range of 190-200 ℃, and increases rapidly above 200 ℃. The viscosities of BMI/PES-15, BMI/PES-10 and BMI/PES-5 resin systems increase rapidly above 180 ℃. SEM shows that these BMI/PES resins exhibit the ripening of phase structure during the temperature range of 180-200 ℃.
2018, 38(6): 71 -76
doi: 10.11868/j.issn.1005-5053.2017.000152
Abstract:
Thermal imidization restricts the application of fluorinated polyimide, but the low temperature imidization could cause a certain impact on its performance. PAA was synthesized with fluorinated monomer 4, 4'-(six fluoro isopropenyl) phthalic anhydride (6FDA) and 4 4'-, two amino -2, 2'- three fluorine biphenyl (TFMB), and then through gradient heating by 80 ℃/1 h, 110 ℃/2 h, 150 ℃/2 h, 200 ℃/1 h, 250 ℃/30 min, 300 ℃/30 min and adding acetic anhydride /pyridine mixture into PAA, two kinds of PI films were prepared and characterized. The test results show that PI films prepared by chemical imidization has better transparency, solubility and mechanical properties, while the PI films prepared by thermal imidization has smaller relative dielectric constant, and higher initial decomposition temperature and higher imidization rate.
Thermal imidization restricts the application of fluorinated polyimide, but the low temperature imidization could cause a certain impact on its performance. PAA was synthesized with fluorinated monomer 4, 4'-(six fluoro isopropenyl) phthalic anhydride (6FDA) and 4 4'-, two amino -2, 2'- three fluorine biphenyl (TFMB), and then through gradient heating by 80 ℃/1 h, 110 ℃/2 h, 150 ℃/2 h, 200 ℃/1 h, 250 ℃/30 min, 300 ℃/30 min and adding acetic anhydride /pyridine mixture into PAA, two kinds of PI films were prepared and characterized. The test results show that PI films prepared by chemical imidization has better transparency, solubility and mechanical properties, while the PI films prepared by thermal imidization has smaller relative dielectric constant, and higher initial decomposition temperature and higher imidization rate.
2018, 38(6): 77 -82
doi: 10.11868/j.issn.1005-5053.2018.000077
Abstract:
Coupling agent is one of the most common surface modifiers which is widely used in the field of absorbing material. Modification of absorbing material by coupling agent is the research hotspot. Herein, the absorbing material was prepared and modified by two kinds of absorbents (Ba(Zn1-xCox)2Fe16O27 and CIP) and AMEO coupling agent. The effect of absorbent modification on the macrostructure of absorbents was investigated by SEM. The electromagnetic properties of Ba(Zn1-xCox)2Fe16O27 and CIP were tested and discussed in detail. The difference between theoretical value and actual value of electromagnetic properties of absorbers was discussed by effective medium theory. The experimental results show that the absorbent modification can adjust the electromagnetic properties of absorbing material. The reflectivity of absorbing material after the modification is less than –10 dB in the range of 8 GHz to 18 GHz, and showes a minimum reflection of –14.5 dB. Furthermore, the absorbing material has a higher tensile strength (6.32 MPa). After the test of resistance to environment, no obvious changes are appeared from the absorbing material, reflectivity and adhesive force. The absorbing material has a good property of resistance to environment.
Coupling agent is one of the most common surface modifiers which is widely used in the field of absorbing material. Modification of absorbing material by coupling agent is the research hotspot. Herein, the absorbing material was prepared and modified by two kinds of absorbents (Ba(Zn1-xCox)2Fe16O27 and CIP) and AMEO coupling agent. The effect of absorbent modification on the macrostructure of absorbents was investigated by SEM. The electromagnetic properties of Ba(Zn1-xCox)2Fe16O27 and CIP were tested and discussed in detail. The difference between theoretical value and actual value of electromagnetic properties of absorbers was discussed by effective medium theory. The experimental results show that the absorbent modification can adjust the electromagnetic properties of absorbing material. The reflectivity of absorbing material after the modification is less than –10 dB in the range of 8 GHz to 18 GHz, and showes a minimum reflection of –14.5 dB. Furthermore, the absorbing material has a higher tensile strength (6.32 MPa). After the test of resistance to environment, no obvious changes are appeared from the absorbing material, reflectivity and adhesive force. The absorbing material has a good property of resistance to environment.
2018, 38(6): 83 -88
doi: 10.11868/j.issn.1005-5053.2017.000202
Abstract:
High performance carbon-reinforced composite materials have become important aeronautical materials. During the service time, the delamination fracture of composite structures is a common failure mode. In this study, in order to investigate the delamination behaviours of T800/epoxy composite materials under different mixture ratios, DCB, ENF and MMB tests were conducted on composite laminates with pre-set 0°/45° interface respectively. From the test, the initial delamination fracture toughness and delamination growth behaviour were obtained. The test results show that the fracture toughness and delamination behaviour are significantly affected by the mixture ratio. With the increase of mixture ratio, the fracture toughness increases, and steady delamination growth behaviour is more difficult to maintain. Based on the data fitting method, a prediction function for fracture toughness of the 0°/45° interface at arbitrary mixture ratio is established, which has some engineering values.
High performance carbon-reinforced composite materials have become important aeronautical materials. During the service time, the delamination fracture of composite structures is a common failure mode. In this study, in order to investigate the delamination behaviours of T800/epoxy composite materials under different mixture ratios, DCB, ENF and MMB tests were conducted on composite laminates with pre-set 0°/45° interface respectively. From the test, the initial delamination fracture toughness and delamination growth behaviour were obtained. The test results show that the fracture toughness and delamination behaviour are significantly affected by the mixture ratio. With the increase of mixture ratio, the fracture toughness increases, and steady delamination growth behaviour is more difficult to maintain. Based on the data fitting method, a prediction function for fracture toughness of the 0°/45° interface at arbitrary mixture ratio is established, which has some engineering values.
2018, 38(6): 89 -96
doi: 10.11868/j.issn.1005-5053.2018.000028
Abstract:
Aimed at the great metallographic structure differences between every part of the large-scale thin-wall complex integral precise titanium alloy casting, a non-destructive evaluation method based on metallographic structure statistical analysis is proposed. Under the non-destructive condition, the casting skin structure information is given by means of handheld microscope. The casting skin structure statistic model is established. And the result of integral casting structure is given. Through comparative analysis between non-destructive evaluation (Method A) and metallography detection of the dissect sample (Method B), the results show that the non-destructive evaluation evaluates the metallographic structure effectively. The mean value and half-width of the grain size distribution curves fit the characteristic of Gaussian distribution. And the grain size mean value in both two methods increase linearly along with the casting thickness, and the slope deviation is within the limits of 6%; the half-width relative deviation increases exponentially along with the casting thickness, approached 26%.
Aimed at the great metallographic structure differences between every part of the large-scale thin-wall complex integral precise titanium alloy casting, a non-destructive evaluation method based on metallographic structure statistical analysis is proposed. Under the non-destructive condition, the casting skin structure information is given by means of handheld microscope. The casting skin structure statistic model is established. And the result of integral casting structure is given. Through comparative analysis between non-destructive evaluation (Method A) and metallography detection of the dissect sample (Method B), the results show that the non-destructive evaluation evaluates the metallographic structure effectively. The mean value and half-width of the grain size distribution curves fit the characteristic of Gaussian distribution. And the grain size mean value in both two methods increase linearly along with the casting thickness, and the slope deviation is within the limits of 6%; the half-width relative deviation increases exponentially along with the casting thickness, approached 26%.
1994, 14(1): 49-55
1998, 18(4): 52-61
2000, 20(1): 55-61
2003, 23(1): 57-62
2002, 22(2): 49-53
2005, 25(4): 10-15,19
2005, 25(1): 25-29,35
2018, 38(2): 70-76
doi: 10.11868/j.issn.1005-5053.2018.001005
2018, 38(4): 101-108
doi: 10.11868/j.issn.1005-5053.2018.000007
2018, 38(5): 24-35
doi: 10.11868/j.issn.1005-5053.2018.000035
2018, 38(4): 64-74
doi: 10.11868/j.issn.1005-5053.2018.000025
2018, 38(6): 1-10
doi: 10.11868/j.issn.1005-5053.2018.000081
2018, 38(5): 47-58
doi: 10.11868/j.issn.1005-5053.2018.000022
2018, 38(2): 1-9
doi: 10.11868/j.issn.1005-5053.2018.001008
2018, 38(4): 37-46
doi: 10.11868/j.issn.1005-5053.2017.000204
2018, 38(3): 10-19
doi: 10.11868/j.issn.1005-5053.2018.001009
2018, 38(2): 10-20
doi: 10.11868/j.issn.1005-5053.2018.001001
2018, 38(2): 86-95
doi: 10.11868/j.issn.1005-5053.2017.000010
2018, 38(3): 40-45
doi: 10.11868/j.issn.1005-5053.2017.000207
2018, 38(4): 47-55
doi: 10.11868/j.issn.1005-5053.2017.000159
2018, 38(5): 74-79
doi: 10.11868/j.issn.1005-5053.2017.000196
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Telephone：010-62496277 E-mail：hkclxb@biam.ac.cn
Supported by Beijing Renhe Information Technology Co. LtdTechnical support：info@rhhz.net