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1Research Progress and Application Perspectives of 4D Printing
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2Research Progress of Metal-Intermetallic Laminated Composites
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3Progress on Self-Healing and Structure-Wave Absorbing Integration of Silicon Carbide Ceramic Matrix Composites
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4Novel Ceramic Materials for Thermal Barrier Coatings
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5Recent progress of 4D printing technology
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6Application and Research Status of Alternative Materials for 3D-printing Technology
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7Research Progress of Laser Shock Treatment in the Field of Material Forming
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8Research Progress on Preforms of C/C Composites
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9Resent development in high-entropy alloys and other high-entropy materials
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10Additive Manufacture of Metamaterials: a Review
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11Application Potential of 4D Printing Technology in Development of Aircraft
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12Research Process in Plasma Spray Physical Vapor Deposited Thermal Barrier Coatings
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13Effect of sintering temperature on microstructure and mechanical behavior of alumina-based ceramic shell by SLS
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14Research progress of BN interphase and its multilayers in SiCf/SiC composites
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15Effect of Mo content on Microstructure and Mechanical Properties of IN718 Alloy
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16Recent Process and Application of Electrochromism
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1First-principle Calculations of Mechanical Properties of Al2Cu, Al2CuMg and MgZn2 Intermetallics in High Strength Aluminum Alloys
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2Effect of Filler Systems on Properties of Fluororubber Vulcanized by Peroxide
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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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5Research Progress and Application Perspectives of 4D Printing
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62018-02-Catalog
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7Effect of sintering temperature on microstructure and mechanical behavior of alumina-based ceramic shell by SLS
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8Research Progress in Preparation and Crystallization Technologies of Amorphous ITO Film
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9Recent Process and Application of Electrochromism
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10Effect of Low Angle Grain Boundaries on Mechanical Properties of DD5 Single Crystal Ni-base Superalloy
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11A Review on Mg-RE Alloys with High Product of Strength and Elongation
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122018-04-Catalog
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13Research Progress in Cemented Carbide with Co-Ni-Al Composite Binder Phase
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14Application and Research Status of Alternative Materials for 3D-printing Technology
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15Progress in Amorphous Transparent Conducting Oxide Thin Films
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16Novel Ceramic Materials for Thermal Barrier Coatings
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Available online
, doi: 10.11868/j.issn.1005-5053.2019.000067
Abstract:
Aeronautical composite stiffened panels are widely used in aeronautical structure design because of their good mechanical properties. In this paper, the compressive buckling and post-buckling mechanical properties of aeronautical composite stiffened panels were studied. Firstly, the compressive stability of composite stiffened panels was calculated by engineering method, and the predictions of the buckling and failure loads of stiffened panels were obtained; secondly, the composite materials were developed. Compressive stability tests of stiffened plates were carried out, and the following results were obtained: (1) buckling and failure modes of the specimens; (2) load-strain and load-displacement relationships of the specimens; (3) buckling and failure loads of the specimens. The results show that the calculated results by engineering method are in good agreement with the test results, and the error of buckling load and failure load are 6.12% and 9.31% respectively. The failure modes of stiffened panels are the delamination of the panels, the bulging and tearing of the skin, the fracture of the stiffeners and the debonding of the stiffeners-panels. The buckling ratio of composite stiffened plates is 1.65, the composite stiffened plates have strong post-buckling bearing capacity. The post-buckling bearing capacity of stiffened plates can be fully applied in engineering to improve the utilization efficiency of structures.
Aeronautical composite stiffened panels are widely used in aeronautical structure design because of their good mechanical properties. In this paper, the compressive buckling and post-buckling mechanical properties of aeronautical composite stiffened panels were studied. Firstly, the compressive stability of composite stiffened panels was calculated by engineering method, and the predictions of the buckling and failure loads of stiffened panels were obtained; secondly, the composite materials were developed. Compressive stability tests of stiffened plates were carried out, and the following results were obtained: (1) buckling and failure modes of the specimens; (2) load-strain and load-displacement relationships of the specimens; (3) buckling and failure loads of the specimens. The results show that the calculated results by engineering method are in good agreement with the test results, and the error of buckling load and failure load are 6.12% and 9.31% respectively. The failure modes of stiffened panels are the delamination of the panels, the bulging and tearing of the skin, the fracture of the stiffeners and the debonding of the stiffeners-panels. The buckling ratio of composite stiffened plates is 1.65, the composite stiffened plates have strong post-buckling bearing capacity. The post-buckling bearing capacity of stiffened plates can be fully applied in engineering to improve the utilization efficiency of structures.
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Available online
, doi: 10.11868/j.issn.1005-5053.2019.000047
Abstract:
Nitride-based ceramic materials have excellent comprehensive properties such as high strength, high modulus, high temperature resistance, thermal shock resistance and wave-transparent performance. They are the main candidates for high-temperature wave-transparent components. The reports about their application are few, and the preparation technologies and properties need to be improved. In this paper, the research progress of nitride ceramics, nitride composite ceramics and nitride ceramic matrix composites was summarized. It is found that the comprehensive properties of porous Si3N4 ceramics, BN-Si3N4 composite ceramics and BNw/Si3N4 composites are excellent, with the dielectric constant less than 5, the dielectric loss less than 0.01, and the room-temperature flexural strength higher than 200 MPa, respectively. In this paper, the existing problems of the studies on the nitride-based ceramic as high-temperature wave-transparent materials were analyzed, which is mainly that the mechanical properties and dielectric properties are difficult to improve in coordination, and the future development direction of the selection of high-temperature wave-transparent material systems and preparation technologies are prospected.
Nitride-based ceramic materials have excellent comprehensive properties such as high strength, high modulus, high temperature resistance, thermal shock resistance and wave-transparent performance. They are the main candidates for high-temperature wave-transparent components. The reports about their application are few, and the preparation technologies and properties need to be improved. In this paper, the research progress of nitride ceramics, nitride composite ceramics and nitride ceramic matrix composites was summarized. It is found that the comprehensive properties of porous Si3N4 ceramics, BN-Si3N4 composite ceramics and BNw/Si3N4 composites are excellent, with the dielectric constant less than 5, the dielectric loss less than 0.01, and the room-temperature flexural strength higher than 200 MPa, respectively. In this paper, the existing problems of the studies on the nitride-based ceramic as high-temperature wave-transparent materials were analyzed, which is mainly that the mechanical properties and dielectric properties are difficult to improve in coordination, and the future development direction of the selection of high-temperature wave-transparent material systems and preparation technologies are prospected.
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Available online
, doi: 10.11868/j.issn.1005-5053.2019.000038
Abstract:
In order to break through the technical bottleneck of traditional metal-ceramic double-layer thermal protective coating which is easy to peel in high temperature environment, the influence of the space travel velocity of the spray gun on temperature field in time domain and space domain of the Mo/8YSZ composite coating was studied. Using ANSYS finite element analysis software, a numerical model for preparing Mo/8YSZ functionally graded thermal barrier coatings by plasma spraying was established, and the thermal properties of the material at different temperatures and the latent heat of phase change of the material were also considered in the model. By analyzing the temperature and temperature gradient of the sprayed component under the different space travel velocities of the spray gun, it is found that at the same time of the spraying process, the greater the travel velocity of the spray gun, the less time the spray gun interacts with the component per unit length, the smaller the maximum temperature value of the component, the higher the uniformity of the temperature distribution on the upper surface of the component, and the smaller the maximum temperature gradient value of the component. The first deposited coating has a preheating effect on the post-deposited coating, and the maximum temperature value of the substrate exhibits a "stepped" increase trend. As the thickness of the coating increases, the thermal resistance of the coating increases, and the fluctuation of the substrate temperature gradually decreases. The temperature gradient of the component can be further reduced by adjusting the travel velocity of the spray gun of each coating, and the temperature gradient of the component can be minimized when the spraying is undertaken in accordance with the sequence of maximum bonding layer, transition layer and minimum ceramic layer.
In order to break through the technical bottleneck of traditional metal-ceramic double-layer thermal protective coating which is easy to peel in high temperature environment, the influence of the space travel velocity of the spray gun on temperature field in time domain and space domain of the Mo/8YSZ composite coating was studied. Using ANSYS finite element analysis software, a numerical model for preparing Mo/8YSZ functionally graded thermal barrier coatings by plasma spraying was established, and the thermal properties of the material at different temperatures and the latent heat of phase change of the material were also considered in the model. By analyzing the temperature and temperature gradient of the sprayed component under the different space travel velocities of the spray gun, it is found that at the same time of the spraying process, the greater the travel velocity of the spray gun, the less time the spray gun interacts with the component per unit length, the smaller the maximum temperature value of the component, the higher the uniformity of the temperature distribution on the upper surface of the component, and the smaller the maximum temperature gradient value of the component. The first deposited coating has a preheating effect on the post-deposited coating, and the maximum temperature value of the substrate exhibits a "stepped" increase trend. As the thickness of the coating increases, the thermal resistance of the coating increases, and the fluctuation of the substrate temperature gradually decreases. The temperature gradient of the component can be further reduced by adjusting the travel velocity of the spray gun of each coating, and the temperature gradient of the component can be minimized when the spraying is undertaken in accordance with the sequence of maximum bonding layer, transition layer and minimum ceramic layer.
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Available online
, doi: 10.11868/j.issn.1005-5053.2019.000014
Abstract:
Through theoretical derivation and finite element simulation, the vibration characteristics of composite laminate with four-edge clamped support under hygrothermal condition were studied. Based on the Mindlin first-order shear deformation theory and the Hamilton principle, taking the effect of hygrothermal stress into account and using the equivalence of temperature and humidity, the constitutive equation of composite laminate affected by the hygrothermal environment was derived. The finite element method was used to solve the vibration characteristic equation of the laminate. Bonding repaired laminate model was established by using the finite element software ABAQUS, and the model was compared with literature results. The effects of different hygrothermal environments and the number of additional patches on the vibration characteristic of the bonding repaired laminate were discussed. The results of the example show that in the hygrothermal environment, the introduction of additional patch reduces the natural frequencies of the various orders of the bonding repaired laminate. When the number of additional patches changes from one to two, the first-order natural frequency decreases further. The effect of increased humidity on natural frequency reduction is greater than that of temperature increase on natural frequency. In the environment where the temperature and humidity are simultaneously increased, the introduction of the additional patch will cause the bonding repaired laminate to reach the state of hygrothermal buckling earlier.
Through theoretical derivation and finite element simulation, the vibration characteristics of composite laminate with four-edge clamped support under hygrothermal condition were studied. Based on the Mindlin first-order shear deformation theory and the Hamilton principle, taking the effect of hygrothermal stress into account and using the equivalence of temperature and humidity, the constitutive equation of composite laminate affected by the hygrothermal environment was derived. The finite element method was used to solve the vibration characteristic equation of the laminate. Bonding repaired laminate model was established by using the finite element software ABAQUS, and the model was compared with literature results. The effects of different hygrothermal environments and the number of additional patches on the vibration characteristic of the bonding repaired laminate were discussed. The results of the example show that in the hygrothermal environment, the introduction of additional patch reduces the natural frequencies of the various orders of the bonding repaired laminate. When the number of additional patches changes from one to two, the first-order natural frequency decreases further. The effect of increased humidity on natural frequency reduction is greater than that of temperature increase on natural frequency. In the environment where the temperature and humidity are simultaneously increased, the introduction of the additional patch will cause the bonding repaired laminate to reach the state of hygrothermal buckling earlier.
2019, 39(6): 1 -2
Abstract:
2019, 39(6): 1 -19
doi: 10.11868/j.issn.1005-5053.2019.000170
Abstract:
High-entropy (HE) materials are defined as novel multi-principal materials that contain several principal elements (usually ≥ 5) in an (equa) equi-molar ratio, and the design concept of HE materials introduces a new way to improve the properties of materials. Due to their unique crystallographic structure characteristics, HE materials show many different characteristics of microstructures and properties compared with conventional materials .The HE materials have great potential applications in many fields. At present, many kinds of high-entropy materials were prepared with excellent properties in mechanics, physics or chemistry, such as high strength and elongation, distinguished thermal stability, wear resistance, magnetic, conductivity and corrosion resistance. This paper reviews the recent research and development of high-entropy alloys, high-entropy ceramics and high-entropy intermetallics, and summarizes their structure characteristics, microstructures, properties and strengthening mechanisms. In the future, high throughput calculation and preparation will be an important and fast way to design this kind of multi-component materials. With the development of materials, the forming and processing technologies of high entropy materials will develop rapidly to meet their diversified application needs.
High-entropy (HE) materials are defined as novel multi-principal materials that contain several principal elements (usually ≥ 5) in an (equa) equi-molar ratio, and the design concept of HE materials introduces a new way to improve the properties of materials. Due to their unique crystallographic structure characteristics, HE materials show many different characteristics of microstructures and properties compared with conventional materials .The HE materials have great potential applications in many fields. At present, many kinds of high-entropy materials were prepared with excellent properties in mechanics, physics or chemistry, such as high strength and elongation, distinguished thermal stability, wear resistance, magnetic, conductivity and corrosion resistance. This paper reviews the recent research and development of high-entropy alloys, high-entropy ceramics and high-entropy intermetallics, and summarizes their structure characteristics, microstructures, properties and strengthening mechanisms. In the future, high throughput calculation and preparation will be an important and fast way to design this kind of multi-component materials. With the development of materials, the forming and processing technologies of high entropy materials will develop rapidly to meet their diversified application needs.
2019, 39(6): 20 -31
doi: 10.11868/j.issn.1005-5053.2019.000116
Abstract:
The application of self-assembled membrane technology in metal surface corrosion protection is more and more extensive. Using simple and effective membrane technology to prepare green and environment-friendly membrane products has become a research hotspot in the field of anti-corrosion membrane. In this paper,the research progress of metal surface self-assembled film preparation technology is summarized.Taking the metal surface self-assembled monolayer membrane and its composite membrane as the research object, the classification, characteristics, applications and anti-corrosion mechanism, etc.of self-assembled membrane technology on the surface of aluminum/aluminum alloy, copper, copper alloy, stainless steel and other active metals are expounded respectively.It is pointed out that the research on the interface bonding between membrane and substrate, mechanism of film formation, mechanism of corrosion protection and so on is not perfect yet, which is still a scientific problem to be solved urgently.
The application of self-assembled membrane technology in metal surface corrosion protection is more and more extensive. Using simple and effective membrane technology to prepare green and environment-friendly membrane products has become a research hotspot in the field of anti-corrosion membrane. In this paper,the research progress of metal surface self-assembled film preparation technology is summarized.Taking the metal surface self-assembled monolayer membrane and its composite membrane as the research object, the classification, characteristics, applications and anti-corrosion mechanism, etc.of self-assembled membrane technology on the surface of aluminum/aluminum alloy, copper, copper alloy, stainless steel and other active metals are expounded respectively.It is pointed out that the research on the interface bonding between membrane and substrate, mechanism of film formation, mechanism of corrosion protection and so on is not perfect yet, which is still a scientific problem to be solved urgently.
2019, 39(6): 32 -45
doi: 10.11868/j.issn.1005-5053.2019.000043
Abstract:
Carbon fiber reinforced polymer (CFRP) has been widely used in the aviation, space and automobile structural parts manufacturing due to its excellent physical and mechanical properties. However, the properties of CFRP materials with inhomogeneity and anisotropy are vastly different from metals. In the process of drilling, it is easy to produce delamination, tearing, burr and other defects, which seriously affect the quality of drilling. Therefore, drilling technology of CFRP-metal stacks has become a difficult problem in aircraft assembly process. This paper summarizes the researches of drilling mechanism of CFRP in recent years. The relationship between chip formation mechanism and fiber orientation angle is generalized. Meanwhile, the relationship between axial drilling force, drilling temperature and tool shape, workpiece material, process parameters is summarized. The causes, detection, evaluation methods and restraining measures of typical machining damage during CFRP drilling processes, such as delamination, burr and tearing are analyzed. The latest advances in material, geometric structure of CFRP drilling tools, and development of simulation technology of CFRP drilling process are expounded. It is also proposed that the establishment of accurate and reliable constitutive model is the key to the research of drilling simulation technology. The development trend of CFRP drilling technology is prospected by introducing new CFRP drilling technologies, such as variable process parameters drilling, robotic automatic drilling and suction-type internal chip removal drilling.
Carbon fiber reinforced polymer (CFRP) has been widely used in the aviation, space and automobile structural parts manufacturing due to its excellent physical and mechanical properties. However, the properties of CFRP materials with inhomogeneity and anisotropy are vastly different from metals. In the process of drilling, it is easy to produce delamination, tearing, burr and other defects, which seriously affect the quality of drilling. Therefore, drilling technology of CFRP-metal stacks has become a difficult problem in aircraft assembly process. This paper summarizes the researches of drilling mechanism of CFRP in recent years. The relationship between chip formation mechanism and fiber orientation angle is generalized. Meanwhile, the relationship between axial drilling force, drilling temperature and tool shape, workpiece material, process parameters is summarized. The causes, detection, evaluation methods and restraining measures of typical machining damage during CFRP drilling processes, such as delamination, burr and tearing are analyzed. The latest advances in material, geometric structure of CFRP drilling tools, and development of simulation technology of CFRP drilling process are expounded. It is also proposed that the establishment of accurate and reliable constitutive model is the key to the research of drilling simulation technology. The development trend of CFRP drilling technology is prospected by introducing new CFRP drilling technologies, such as variable process parameters drilling, robotic automatic drilling and suction-type internal chip removal drilling.
2019, 39(6): 46 -62
doi: 10.11868/j.issn.1005-5053.2019.000042
Abstract:
Electrochromic technology has been widely used in many fields, such as building windows and car rear-view mirrors. Ion storage layers (generally anodic electrochromic materials) are significant for improving the performance of electrochromic devices and realizing the application of the technology. Its role is to store and supply the ions needed for the color change reaction, maintaining the charge balance of the entire electrochromic process. At present, the most typical anodic electrochromic material is nickel oxide(NiO). The cheap NiO film has high coloration efficiency and large range of optical transmittance, so it is widely used in the electrochromic technology. This paper overviews the research progress of anodic electrochromic materials in recent years, including material classification, working principle and characteristic requirement, and also introduces the film preparation methods. Developing simple and cost-effective film preparation process is the research focus of electrochromic technology. At the same time, some methods for improving the performance of anodic electrochromic materials, and prospects the development trend are introduced.
Electrochromic technology has been widely used in many fields, such as building windows and car rear-view mirrors. Ion storage layers (generally anodic electrochromic materials) are significant for improving the performance of electrochromic devices and realizing the application of the technology. Its role is to store and supply the ions needed for the color change reaction, maintaining the charge balance of the entire electrochromic process. At present, the most typical anodic electrochromic material is nickel oxide(NiO). The cheap NiO film has high coloration efficiency and large range of optical transmittance, so it is widely used in the electrochromic technology. This paper overviews the research progress of anodic electrochromic materials in recent years, including material classification, working principle and characteristic requirement, and also introduces the film preparation methods. Developing simple and cost-effective film preparation process is the research focus of electrochromic technology. At the same time, some methods for improving the performance of anodic electrochromic materials, and prospects the development trend are introduced.
2019, 39(6): 63 -72
doi: 10.11868/j.issn.1005-5053.2019.000072
Abstract:
From an engineering practical perspective, modification, thermal analysis for curing properties of cyanate ester resin, as well as development of adhesives and composites based on cyanate ester resin are reviewed. Modification of cyanate involves toughening by rubbers or thermoplastics, synergistic modification with epoxy and bismaleimide, and so on. The adhesive development examination results show that the satisfied lap shear strength and peel strength are gained by using hydroxyl-terminated poly (ether sulfone) (PES-OH), and moreover, relative lower dielectric constant and lower loss tangent are maintained. Although the strength can be improved by adding epoxy, such kind adhesive composition still has relative poor electrical properties. The developed cyanate adhesive SY-CN has higher lap shear strengths up to 30 MPa at temperatures below 175 ℃, lower dielectric loss of 0.0065, unchanged strength level after 200 hours of hot-aging at 200 ℃, and satisfied anti-peel performance, e.g. sandwich honeycomb climbing drum peel strength is up to 83.2 N•mm/mm. More and more studies on cure kinetic thermal analysis have indicated that the increase or decrease in curing activation energy data of modified cyanate ester resin versus unmodified cyanate ester resin can be synchronized with up or down of maximum cure peak temperature from the differential scanning calorimetry (DSC) curves, and also can be changed oppositely. Cyanate ester resin modified with hydroxyl-terminated poly (ether sulfone) (PES-OH) has lower maximum cure peak temperature of about 20 ℃ reduction versus unmodified cyanate, but the curing activation energy increase which can be due to change of reaction mechanism and steric hindrance effect. Based on change of maximum cure peak temperatures (Tp) with different heating rate data (ϕ) from DSC curves, a linear equation of Tp = T1 + ΔT ln ϕ has been established, then, the curing temperature parameter can be more reasonably determined.
From an engineering practical perspective, modification, thermal analysis for curing properties of cyanate ester resin, as well as development of adhesives and composites based on cyanate ester resin are reviewed. Modification of cyanate involves toughening by rubbers or thermoplastics, synergistic modification with epoxy and bismaleimide, and so on. The adhesive development examination results show that the satisfied lap shear strength and peel strength are gained by using hydroxyl-terminated poly (ether sulfone) (PES-OH), and moreover, relative lower dielectric constant and lower loss tangent are maintained. Although the strength can be improved by adding epoxy, such kind adhesive composition still has relative poor electrical properties. The developed cyanate adhesive SY-CN has higher lap shear strengths up to 30 MPa at temperatures below 175 ℃, lower dielectric loss of 0.0065, unchanged strength level after 200 hours of hot-aging at 200 ℃, and satisfied anti-peel performance, e.g. sandwich honeycomb climbing drum peel strength is up to 83.2 N•mm/mm. More and more studies on cure kinetic thermal analysis have indicated that the increase or decrease in curing activation energy data of modified cyanate ester resin versus unmodified cyanate ester resin can be synchronized with up or down of maximum cure peak temperature from the differential scanning calorimetry (DSC) curves, and also can be changed oppositely. Cyanate ester resin modified with hydroxyl-terminated poly (ether sulfone) (PES-OH) has lower maximum cure peak temperature of about 20 ℃ reduction versus unmodified cyanate, but the curing activation energy increase which can be due to change of reaction mechanism and steric hindrance effect. Based on change of maximum cure peak temperatures (Tp) with different heating rate data (ϕ) from DSC curves, a linear equation of Tp = T1 + ΔT ln ϕ has been established, then, the curing temperature parameter can be more reasonably determined.
2019, 39(6): 73 -80
doi: 10.11868/j.issn.1005-5053.2019.000036
Abstract:
Co-based superalloys casting ingots were prepared by vacuum smelting furnaces, and the influence of Ni content on the microstructure and lattice misfit of Co-based superalloys were studied by X-ray diffraction analysis (XRD) and scanning electron microscope (SEM). The effect of Ni content on the properties of Co-based superalloys was studied by high temperature compression test. The results show that the average size of the γ′ phase increases with the increment of Ni content. When the Ni content rises from 0% to 15%, the volume fraction of the γ′ phase in the alloy increases gradually, which peaks at 15% Ni content.After that the volume fraction of the γ′ phase decreases slightly when the Ni content increases to 20%.When the Ni content increases from0 to 10%, the lattice misfit between γ/γ′ phase decreases.While the misfit of the γ/γ′ phase increases slightly when the Ni content raises to 20%.The Ni content increases from 10% to 15%, the lattice misfit of the γ/γ′ phase begins to decreases again. Through the test of high temperature compression of the alloy, the yield strength of the alloy with 5% Ni content is the highest.
Co-based superalloys casting ingots were prepared by vacuum smelting furnaces, and the influence of Ni content on the microstructure and lattice misfit of Co-based superalloys were studied by X-ray diffraction analysis (XRD) and scanning electron microscope (SEM). The effect of Ni content on the properties of Co-based superalloys was studied by high temperature compression test. The results show that the average size of the γ′ phase increases with the increment of Ni content. When the Ni content rises from 0% to 15%, the volume fraction of the γ′ phase in the alloy increases gradually, which peaks at 15% Ni content.After that the volume fraction of the γ′ phase decreases slightly when the Ni content increases to 20%.When the Ni content increases from0 to 10%, the lattice misfit between γ/γ′ phase decreases.While the misfit of the γ/γ′ phase increases slightly when the Ni content raises to 20%.The Ni content increases from 10% to 15%, the lattice misfit of the γ/γ′ phase begins to decreases again. Through the test of high temperature compression of the alloy, the yield strength of the alloy with 5% Ni content is the highest.
2019, 39(6): 81 -89
doi: 10.11868/j.issn.1005-5053.2018.000127
Abstract:
Ceramic-metal based functional graded materials (FGMs) are expected to be used in the design of airplane tail nozzle, not only because of their material characteristics varies with the changing of thickness continuously, but also because of the speed of heat conduction of ceramic material in the inner ring and the high strength of metal in the outer ring. The purpose of this article is to discuss the impacts of different heat flux density, ceramic volume fraction index and temperature on the thermal stress and heat conduction of FGMs shell. Firstly, the physical property model of FGMs was set up, and the effects of different kinds of parameters on the thermal physical properties were discussed. Thereafter, the thermal stress equation of the FGMs cylindrical shell was derived, and the change law of thermal stress under different conditions was explored. In the end, the heat conduction equation of FGMs shell was derived by energy equilibrium theorem and the impacts of heat flux density on the heat conduction were discussed. Results indicate that the thermal stress increases slowly with the increasing of the ceramic volume fraction index when the heat flux density is constant. The stress in the outer side of the cylindrical shell is larger than that of the inner side. The temperature of an arbitrary section increases with the increasing of heat flux density. And the trend is more obvious as the heat flux density becomes bigger.
Ceramic-metal based functional graded materials (FGMs) are expected to be used in the design of airplane tail nozzle, not only because of their material characteristics varies with the changing of thickness continuously, but also because of the speed of heat conduction of ceramic material in the inner ring and the high strength of metal in the outer ring. The purpose of this article is to discuss the impacts of different heat flux density, ceramic volume fraction index and temperature on the thermal stress and heat conduction of FGMs shell. Firstly, the physical property model of FGMs was set up, and the effects of different kinds of parameters on the thermal physical properties were discussed. Thereafter, the thermal stress equation of the FGMs cylindrical shell was derived, and the change law of thermal stress under different conditions was explored. In the end, the heat conduction equation of FGMs shell was derived by energy equilibrium theorem and the impacts of heat flux density on the heat conduction were discussed. Results indicate that the thermal stress increases slowly with the increasing of the ceramic volume fraction index when the heat flux density is constant. The stress in the outer side of the cylindrical shell is larger than that of the inner side. The temperature of an arbitrary section increases with the increasing of heat flux density. And the trend is more obvious as the heat flux density becomes bigger.
2019, 39(6): 90 -98
doi: 10.11868/j.issn.1005-5053.2019.000091
Abstract:
LiCoO2 thin films were prepared on single crystal Si (100) by magnetron sputtering method and then annealed by different annealing temperatures, holding times and atmospheres. The effects of annealing processes on the surface morphologies, compositions, crystal structures and mechanical properties of LiCoO2 films were investigated. The results show that the surface average roughness of LiCoO2 film is reduced from 11.63 nm to 6.13 nm; annealing atmosphere has the greatest influence on the surface morphologies of LiCoO2 films. The LiCoO2 film composition is destroyed due to Li2O, CoO, Co3O4 by-products formed during annealing process. LiCoO2 film are crystallized under any annealing conditions, the average grain size is about 30 nm, annealing temperature has the greatest influence on the grain size and residual stress. After annealing, the hardness and young's modulus of LiCoO2 films are increased by an order of magnitude. Under the optimal annealing process (600 ℃, 60 min, pure O2 atmosphere), the ratio of H3/Er2 is 0.03 GPa, which shows excellent resistance to plastic deformation.
LiCoO2 thin films were prepared on single crystal Si (100) by magnetron sputtering method and then annealed by different annealing temperatures, holding times and atmospheres. The effects of annealing processes on the surface morphologies, compositions, crystal structures and mechanical properties of LiCoO2 films were investigated. The results show that the surface average roughness of LiCoO2 film is reduced from 11.63 nm to 6.13 nm; annealing atmosphere has the greatest influence on the surface morphologies of LiCoO2 films. The LiCoO2 film composition is destroyed due to Li2O, CoO, Co3O4 by-products formed during annealing process. LiCoO2 film are crystallized under any annealing conditions, the average grain size is about 30 nm, annealing temperature has the greatest influence on the grain size and residual stress. After annealing, the hardness and young's modulus of LiCoO2 films are increased by an order of magnitude. Under the optimal annealing process (600 ℃, 60 min, pure O2 atmosphere), the ratio of H3/Er2 is 0.03 GPa, which shows excellent resistance to plastic deformation.
2018, 38(2): 70-76
doi: 10.11868/j.issn.1005-5053.2018.001005
2018, 38(4): 37-46
doi: 10.11868/j.issn.1005-5053.2017.000204
2018, 38(2): 10-20
doi: 10.11868/j.issn.1005-5053.2018.001001
2019, 39(2): 1-9
doi: 10.11868/j.issn.1005-5053.2018.000041
2016, 36(4): 89-98
doi: 10.11868/j.issn.1005-5053.2016.4.013
2018, 38(6): 1-10
doi: 10.11868/j.issn.1005-5053.2018.000081
2018, 38(2): 86-95
doi: 10.11868/j.issn.1005-5053.2017.000010
2019, 39(6): 1-19
doi: 10.11868/j.issn.1005-5053.2019.000170
2018, 38(3): 10-19
doi: 10.11868/j.issn.1005-5053.2018.001009
2018, 38(2): 59-69
doi: 10.11868/j.issn.1005-5053.2018.001002
2018, 38(2): 1-9
doi: 10.11868/j.issn.1005-5053.2018.001008
2019, 39(5): 13-23
doi: 10.11868/j.issn.1005-5053.2019.000101
2018, 38(4): 64-74
doi: 10.11868/j.issn.1005-5053.2018.000025
2016, 36(3): 108-123
doi: 10.11868/j.issn.1005-5053.2016.3.012
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Copyright © 2015 Editorial Board of Journal of Aeronautical Materials
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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
Address：P.Q.BOX 81-44,Beijing 100095,China
Telephone：010-62496277 E-mail：hkclxb@biam.ac.cn
Supported by Beijing Renhe Information Technology Co. LtdTechnical support：info@rhhz.net