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1CHALLENGE AND DEVELOPEMENT TRENDS TO FUTURE AERO ENGINE MATERIALS
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2Development of advanced polymer composites
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3Progress on Electrically Conductive Silicone Rubber
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4Damage characterization and failure analysis in fiber reinforced composites
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5Review and prospect on developments of cast superalloys
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6Strengthening mechanisms of metal matrix composites
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7POLYMERS OBTAINED FROM BENZOCYCLOBUTENES
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8Investigation on Indentation Creep by Depth Sensing Indentation
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9Study on In-Plane Anisotropy of 2524 Aluminum Alloy Sheet
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10Control and relief of residual stresses in high-strength aluminum alloy parts for aerospace industry
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11Study on Fatigue Performance of 7075-T651 Aluminum Alloys
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12Development and Application of P/M Superalloy
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13Development of honeycomb cell structure and materials
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14High-temperature polyimide composites and its application in aeronautical engine
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15Progress on Self-Healing Silicon Carbide Ceramic Matrix Composites and Its Applications
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16Progress of Advanced Near Net-Shape Investment Casting Technology of Superalloys
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1Microstructure and mechanical properties of ultra-high strength TiCp/Mg-1.4Zn-2.6Ca-0.5Mn nanocomposite after hot extrusion
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2Resent development in high-entropy alloys and other high-entropy materials
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3Recent Process and Application of Electrochromism
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4Research Process in Plasma Spray Physical Vapor Deposited Thermal Barrier Coatings
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5Method on measuring fibre permeabilities in resin transfer molding
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6First-principle Calculations of Mechanical Properties of Al2Cu, Al2CuMg and MgZn2 Intermetallics in High Strength Aluminum Alloys
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7Research Progress and Application Perspectives of 4D Printing
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8Research Progress in Preparation and Crystallization Technologies of Amorphous ITO Film
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9Application and Research Status of Alternative Materials for 3D-printing Technology
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10Additive Manufacture of Metamaterials: a Review
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11Effect of Rare Earth Y on Microstructure and Properties of Sn-58Bi Solder Alloy
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12Research Progress in Cemented Carbide with Co-Ni-Al Composite Binder Phase
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13Novel Ceramic Materials for Thermal Barrier Coatings
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14Effect of Filler Systems on Properties of Fluororubber Vulcanized by Peroxide
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15Effect of sintering temperature on microstructure and mechanical behavior of alumina-based ceramic shell by SLS
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16Research Progress of Metal-Intermetallic Laminated Composites
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Available online
, doi: 10.11868/j.issn.1005-5053.2020.000189
Abstract:
The spherical FeSiAl alloy powder was used as the raw material absorbent, and the flakes were made by extrusion under the action of ball milling to obtain excellent low-frequency adsorbing performance. The phase composition, microstructure and electromagnetic characteristics of the flaky FeSiAl alloy were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and vector network analyzer (VNA), the microwave absorption performance was studied. The results indicate that the absorption peaks of FeSiAl alloy absorbent are located in X and Ku bands. The flaky FeSiAl alloy containing 70%(mass fraction)as filler with the thickness of 4.00 mm exhibits strong dielectric and magnetic losses as well as a good impedance matching property. It displays extremely strong electromagnetic wave absorption with reflection loss of -32.8 dB at 2.25 GHz, and the low frequency wave absorbing performance is improved significantly compared with spherical FeSiAl alloy,.
The spherical FeSiAl alloy powder was used as the raw material absorbent, and the flakes were made by extrusion under the action of ball milling to obtain excellent low-frequency adsorbing performance. The phase composition, microstructure and electromagnetic characteristics of the flaky FeSiAl alloy were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and vector network analyzer (VNA), the microwave absorption performance was studied. The results indicate that the absorption peaks of FeSiAl alloy absorbent are located in X and Ku bands. The flaky FeSiAl alloy containing 70%(mass fraction)as filler with the thickness of 4.00 mm exhibits strong dielectric and magnetic losses as well as a good impedance matching property. It displays extremely strong electromagnetic wave absorption with reflection loss of -32.8 dB at 2.25 GHz, and the low frequency wave absorbing performance is improved significantly compared with spherical FeSiAl alloy,.
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Available online
, doi: 10.11868/j.issn.1005-5053.2020.000163
Abstract:
The fiber metal laminate is mainly used in the fuselage wall board, wing skin and other key parts of the aircraft. The structural parts mentioned above bear a large bending moment during the service, which requires that the fiber metal laminate should have the ability to resist bending deformation. In this study, fiber rare earth magnesium alloy super hybrid laminate, a new type of fuselage structure material was used as the research object. Three-point bending was used to test the bending strength of unidirectional and cross-ply rare earth magnesium alloy super hybrid laminates under different span-to-thickness ratios (L/h). SEM was used to observe the bending failure morphology of the laminate, and the progressive damage behavior of the laminate during the bending process was analyzed with finite element simulation. The research results show that the different L/h values have a certain effect on the bending strength of rare earth magnesium alloy super hybrid laminates. The effective bending failure L/h values of unidirectional and orthogonal rare earth magnesium alloy super hybrid laminates are 16-22 and 16-20 respectively. Through SEM observation and finite element analysis, it is concluded that the bending failure modes of laminate include elastic stage, plastic stage, fiber and epoxy resin matrix fracture stage, rare earth magnesium alloy fracture stage and laminate delamination stage.
The fiber metal laminate is mainly used in the fuselage wall board, wing skin and other key parts of the aircraft. The structural parts mentioned above bear a large bending moment during the service, which requires that the fiber metal laminate should have the ability to resist bending deformation. In this study, fiber rare earth magnesium alloy super hybrid laminate, a new type of fuselage structure material was used as the research object. Three-point bending was used to test the bending strength of unidirectional and cross-ply rare earth magnesium alloy super hybrid laminates under different span-to-thickness ratios (L/h). SEM was used to observe the bending failure morphology of the laminate, and the progressive damage behavior of the laminate during the bending process was analyzed with finite element simulation. The research results show that the different L/h values have a certain effect on the bending strength of rare earth magnesium alloy super hybrid laminates. The effective bending failure L/h values of unidirectional and orthogonal rare earth magnesium alloy super hybrid laminates are 16-22 and 16-20 respectively. Through SEM observation and finite element analysis, it is concluded that the bending failure modes of laminate include elastic stage, plastic stage, fiber and epoxy resin matrix fracture stage, rare earth magnesium alloy fracture stage and laminate delamination stage.
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Available online
, doi: 10.11868/j.issn.1005-5053.2020.000161
Abstract:
Solid propellant is an important source of power for rockets and missiles, and its performance improvement is of great significance for improving the combat capability of missile weapons. 3D printing technology as a focus on advanced manufacturing technology, able to complete high-precision, high-complexity device manufacturing that is difficult to achieve by traditional manufacturing processes, solve the problems of uneven mixing, poor product consistency, and low safety, which are difficult to solve by traditional solid propellant pouring process, has broad prospects in the field of solid propellant manufacture.. The slow progress of the research on the preparation of solid propellant by 3D printing is mainly due to the two major problems of safety and process bottleneck. In view of the safety issues of solid propellant 3D printing, solid propellant 3D printing and related work are divided into three stages: 3D printing of partial energetic components, 3D printing of mixed propellants, and 3D printing of solid propellants. The safe printability of energetic components should be demonstrated step by step. In review of the bottleneck problem of solid propellant 3D printing process, the development progress of 3D printing propellant special slurry and equipment is introduced. From the current achievements and development, the future research on solid propellant 3D printing should focus on the development of special formulation and the realization of large-scale printing.
Solid propellant is an important source of power for rockets and missiles, and its performance improvement is of great significance for improving the combat capability of missile weapons. 3D printing technology as a focus on advanced manufacturing technology, able to complete high-precision, high-complexity device manufacturing that is difficult to achieve by traditional manufacturing processes, solve the problems of uneven mixing, poor product consistency, and low safety, which are difficult to solve by traditional solid propellant pouring process, has broad prospects in the field of solid propellant manufacture.. The slow progress of the research on the preparation of solid propellant by 3D printing is mainly due to the two major problems of safety and process bottleneck. In view of the safety issues of solid propellant 3D printing, solid propellant 3D printing and related work are divided into three stages: 3D printing of partial energetic components, 3D printing of mixed propellants, and 3D printing of solid propellants. The safe printability of energetic components should be demonstrated step by step. In review of the bottleneck problem of solid propellant 3D printing process, the development progress of 3D printing propellant special slurry and equipment is introduced. From the current achievements and development, the future research on solid propellant 3D printing should focus on the development of special formulation and the realization of large-scale printing.
2021, 41(2): 1 -15
doi: 10.11868/j.issn.1005-5053.2020.000158
Abstract:
Additive manufacturing technology (AM) is a new type of manufacturing technology based on the discrete-stacking principle and processing component with computer model data. Selective laser melting (SLM) is an important technology in the field of additive manufacturing. With its integrated manufacturing characteristics and significant advantages in the field of complex structural parts manufacturing, it has become a key development technology and frontier direction in the field of aerospace manufacturing. This article reviews the material system and application fields of SLM technology, and mainly analyzes the latest process research of SLM technology and typical applications in the aerospace field. It focuses on the research progress and results of SLM iron-based alloys, nickel-based alloys, titanium alloys and aluminum alloys. While SLM technology is widely used in various fields, there are also many problems and shortcomings, such as many internal defects of forming materials, cracks and deformations of high-performance materials, lack of standard systems, and low compatibility of powder materials. Constraints require further in-depth work in these areas.
Additive manufacturing technology (AM) is a new type of manufacturing technology based on the discrete-stacking principle and processing component with computer model data. Selective laser melting (SLM) is an important technology in the field of additive manufacturing. With its integrated manufacturing characteristics and significant advantages in the field of complex structural parts manufacturing, it has become a key development technology and frontier direction in the field of aerospace manufacturing. This article reviews the material system and application fields of SLM technology, and mainly analyzes the latest process research of SLM technology and typical applications in the aerospace field. It focuses on the research progress and results of SLM iron-based alloys, nickel-based alloys, titanium alloys and aluminum alloys. While SLM technology is widely used in various fields, there are also many problems and shortcomings, such as many internal defects of forming materials, cracks and deformations of high-performance materials, lack of standard systems, and low compatibility of powder materials. Constraints require further in-depth work in these areas.
2021, 41(2): 16 -31
doi: 10.11868/j.issn.1005-5053.2020.000134
Abstract:
Structural lightweight is an important development trend in aerospace and automotive fields, and the demand for lightweight metal materials represented by aluminum alloy, magnesium alloy, and titanium alloy is increasing continuously. Predicting the damage and fracture behavior of advanced metal materials is the key to forming process design and service performance evaluation of high - performance aerospace components, and the development of advanced ductile fracture criteria (DFCs) is the main approach. This paper firstly introduces the microscopic mechanism of ductile fracture of metals, including the shear fracture dominated by shear or compression stress, the tensile fracture dominated by tensile stress, and the mixed fracture. Then, the development history, characteristics, and applications of the traditional uncoupled DFCs are reviewed, and several typical uncoupled ductile fracture models established in recent years as well as their main characteristics and advantages are emphatically discussed. The traditional uncoupled DFCs usually only consider the influence of maximum principal stress or average stress on damage/fracture, and ignore the effect of deviatoric stress, it is not suitable for the prediction of fracture behavior of materials under small stress triaxiality or complex stress state. The recently developed DFCs are more suitable for complex strain path and stress state by considering the joint influence of both stress triaxiality and Lode angle parameter on damage evolution. Whereafter, the development status and typical applications of uncoupled DFCs in aeronautic metals such as aluminum alloy, magnesium alloy, and titanium alloy are reviewed. Finally, this work ends with prospecting the development trend and research direction of DFCs. According to the deformation characteristics of advanced structural metals, new uncoupled DFCs should comprehensively consider the effects of stress state, strain rate, temperature and anisotropy on damage fracture, so as to make it have better applicability and prediction accuracy.
Structural lightweight is an important development trend in aerospace and automotive fields, and the demand for lightweight metal materials represented by aluminum alloy, magnesium alloy, and titanium alloy is increasing continuously. Predicting the damage and fracture behavior of advanced metal materials is the key to forming process design and service performance evaluation of high - performance aerospace components, and the development of advanced ductile fracture criteria (DFCs) is the main approach. This paper firstly introduces the microscopic mechanism of ductile fracture of metals, including the shear fracture dominated by shear or compression stress, the tensile fracture dominated by tensile stress, and the mixed fracture. Then, the development history, characteristics, and applications of the traditional uncoupled DFCs are reviewed, and several typical uncoupled ductile fracture models established in recent years as well as their main characteristics and advantages are emphatically discussed. The traditional uncoupled DFCs usually only consider the influence of maximum principal stress or average stress on damage/fracture, and ignore the effect of deviatoric stress, it is not suitable for the prediction of fracture behavior of materials under small stress triaxiality or complex stress state. The recently developed DFCs are more suitable for complex strain path and stress state by considering the joint influence of both stress triaxiality and Lode angle parameter on damage evolution. Whereafter, the development status and typical applications of uncoupled DFCs in aeronautic metals such as aluminum alloy, magnesium alloy, and titanium alloy are reviewed. Finally, this work ends with prospecting the development trend and research direction of DFCs. According to the deformation characteristics of advanced structural metals, new uncoupled DFCs should comprehensively consider the effects of stress state, strain rate, temperature and anisotropy on damage fracture, so as to make it have better applicability and prediction accuracy.
2021, 41(2): 32 -44
doi: 10.11868/j.issn.1005-5053.2020.000137
Abstract:
Spark discharge phenomenon in solution is a typical characteristic in metal microarc oxidation (MAO) surface treatment, and the optical emission spectroscopy (OES) is an effective way of characterizing micro-discharge optical emission spectra and studying the MAO mechanism. In this paper, the research status of OES analyses in MAO process of Al, Mg, Ti and their alloys was reviewed, the calculation principle of electron temperature and density in microarc plasma discharge channels was introduced, and the influence of the plasma discharge behavior on the microstructure of MAO coatings at different metals, electrical parameters and electrolyte solutions was evaluated. Furthermore, the different discharge models on the basis of OES analyses were also discussed. The plasma temperature in microarc discharge zone for different metals calculated from OES was in the range of 3000 - 10000 K, which provided the evidence for the growth mechanism of ceramic coatings enhanced by quick molten-solidification process in discharge channel.
Spark discharge phenomenon in solution is a typical characteristic in metal microarc oxidation (MAO) surface treatment, and the optical emission spectroscopy (OES) is an effective way of characterizing micro-discharge optical emission spectra and studying the MAO mechanism. In this paper, the research status of OES analyses in MAO process of Al, Mg, Ti and their alloys was reviewed, the calculation principle of electron temperature and density in microarc plasma discharge channels was introduced, and the influence of the plasma discharge behavior on the microstructure of MAO coatings at different metals, electrical parameters and electrolyte solutions was evaluated. Furthermore, the different discharge models on the basis of OES analyses were also discussed. The plasma temperature in microarc discharge zone for different metals calculated from OES was in the range of 3000 - 10000 K, which provided the evidence for the growth mechanism of ceramic coatings enhanced by quick molten-solidification process in discharge channel.
Process control and mechanical properties of graphene/Al composites based on flaky powder metallurgy
2021, 41(2): 45 -52
doi: 10.11868/j.issn.1005-5053.2020.000184
Abstract:
Graphene/Al composites have the characteristics of high strengthening efficiency, synergistic improvement of strong plasticity, and excellent comprehensive performance, which is expected to break through the bottleneck problem of poor strength- plasticity matching of metal matrix composites. However, the dispersion of graphene is an important issue that plagues the preparation of materials. The flaky powder metallurgy technology based on the mechanical ball-milling process can transform the spherical aluminum powder into flakes and realize the uniform dispersion of graphene. In this study, the mechanical ball-milling process was controlled by adding a process control agent (polydimethylsiloxane, PDMS) to prepare flaky Al powder, combined with pressure infiltration technology to prepare 0.6%(mass fraction) GNPs/6061Al composites. The results show that the diameter of flaky aluminum powder increases first and then stabilizes with the prolongation of milling time. As the viscosity of process control agent increases, the diameter of flaky aluminum powder is increased, and the flaky effect of aluminum powder is more obvious. At the same time, the viscosity of graphene defect content decreases first and then increases. Moreover, it is revealed that the graphene defects show a decreasing and increasing change pattern as the viscosity increased. Combined with the structure characterization and mechanical property test, the relationship between properties and structure is discussed, which has provided a reference for the subsequent preparation of graphene/Al composites.
Graphene/Al composites have the characteristics of high strengthening efficiency, synergistic improvement of strong plasticity, and excellent comprehensive performance, which is expected to break through the bottleneck problem of poor strength- plasticity matching of metal matrix composites. However, the dispersion of graphene is an important issue that plagues the preparation of materials. The flaky powder metallurgy technology based on the mechanical ball-milling process can transform the spherical aluminum powder into flakes and realize the uniform dispersion of graphene. In this study, the mechanical ball-milling process was controlled by adding a process control agent (polydimethylsiloxane, PDMS) to prepare flaky Al powder, combined with pressure infiltration technology to prepare 0.6%(mass fraction) GNPs/6061Al composites. The results show that the diameter of flaky aluminum powder increases first and then stabilizes with the prolongation of milling time. As the viscosity of process control agent increases, the diameter of flaky aluminum powder is increased, and the flaky effect of aluminum powder is more obvious. At the same time, the viscosity of graphene defect content decreases first and then increases. Moreover, it is revealed that the graphene defects show a decreasing and increasing change pattern as the viscosity increased. Combined with the structure characterization and mechanical property test, the relationship between properties and structure is discussed, which has provided a reference for the subsequent preparation of graphene/Al composites.
2021, 41(2): 53 -60
doi: 10.11868/j.issn.1005-5053.2019.000046
Abstract:
In this work, numerical simulation was used to investigate the distribution of cooling rate during DC semi-continuous casting of 4032 aluminum alloy billets with the diameters of ϕ120 mm, ϕ300 mm and ϕ500 mm. Further, the effect of cooling rate on the modification of eutectic silicon by Sr addition was investigated. The simulation results indicate that the cooling rate from the surface to the center of the billet generally decreases. As the billet diameter increases, the sump depth becomes deeper, the distance between the isothermal lines of liquidus and solidus becomes larger, and the cooling rate at the billet center decreases sharply. The cooling rate affects the modification results of eutectic silicon by Sr addition. When the cooling rate is higher than 1.8 K/s, Sr addition can achieve excellent modification results. However, as the cooling rate decreases, the modification of eutectic silicon becomes worse, even the Sr contents are the same. At the industrial casting conditions, the cooling rates of inner part of the ϕ500 mm billet are below 1 K/s. At this low cooling rate, the Sr content of 0.033%-0.036% is not enough to modify the eutectic silicon any more. To the billet with the diameter as large as 500 mm, the casting speed is the most important factor that influence the cooling rate distribution. But the influenced area is only limited within the distance of R/2 to the surface, and little influence to the center of the billet.
In this work, numerical simulation was used to investigate the distribution of cooling rate during DC semi-continuous casting of 4032 aluminum alloy billets with the diameters of ϕ120 mm, ϕ300 mm and ϕ500 mm. Further, the effect of cooling rate on the modification of eutectic silicon by Sr addition was investigated. The simulation results indicate that the cooling rate from the surface to the center of the billet generally decreases. As the billet diameter increases, the sump depth becomes deeper, the distance between the isothermal lines of liquidus and solidus becomes larger, and the cooling rate at the billet center decreases sharply. The cooling rate affects the modification results of eutectic silicon by Sr addition. When the cooling rate is higher than 1.8 K/s, Sr addition can achieve excellent modification results. However, as the cooling rate decreases, the modification of eutectic silicon becomes worse, even the Sr contents are the same. At the industrial casting conditions, the cooling rates of inner part of the ϕ500 mm billet are below 1 K/s. At this low cooling rate, the Sr content of 0.033%-0.036% is not enough to modify the eutectic silicon any more. To the billet with the diameter as large as 500 mm, the casting speed is the most important factor that influence the cooling rate distribution. But the influenced area is only limited within the distance of R/2 to the surface, and little influence to the center of the billet.
2021, 41(2): 61 -71
doi: 10.11868/j.issn.1005-5053.2020.000058
Abstract:
The casting simulation software ProCAST was used to achieve the simulation of the filling and solidification process of the high Nb-TiAl alloy impeller investment casting. The influence of the casting and filling process on the filling and solidification characteristics of alloy melt filling, shrinkage cavity and porosity was studied, and the corresponding process was optimized. The casting test and the non-destructive testing analysis of the casting were carried out, and the anatomical analysis of the casting was performed to verify the distribution of the shrinkage cavity and porosity. The mechanical properties of the impeller at room temperature and high temperature were studied using attached test rods. The results show that ProCAST software is more accurate in predicting shrinkage cavity and porosity of the high Nb-TiAl casting, and the process scheme is optimized by simulation and prediction results to avoid the formation of large shrinkage cavity and porosity in casting, only micro shrinkage cavity less than 22 μm is existed in the final casting. All castings are fully filled, with the tensile strength about 580 MPa at room temperature and about 450 MPa at high temperature of 850 ℃.
The casting simulation software ProCAST was used to achieve the simulation of the filling and solidification process of the high Nb-TiAl alloy impeller investment casting. The influence of the casting and filling process on the filling and solidification characteristics of alloy melt filling, shrinkage cavity and porosity was studied, and the corresponding process was optimized. The casting test and the non-destructive testing analysis of the casting were carried out, and the anatomical analysis of the casting was performed to verify the distribution of the shrinkage cavity and porosity. The mechanical properties of the impeller at room temperature and high temperature were studied using attached test rods. The results show that ProCAST software is more accurate in predicting shrinkage cavity and porosity of the high Nb-TiAl casting, and the process scheme is optimized by simulation and prediction results to avoid the formation of large shrinkage cavity and porosity in casting, only micro shrinkage cavity less than 22 μm is existed in the final casting. All castings are fully filled, with the tensile strength about 580 MPa at room temperature and about 450 MPa at high temperature of 850 ℃.
2021, 41(2): 72 -81
doi: 10.11868/j.issn.1005-5053.2020.000129
Abstract:
TiAl alloy was electrochemically anodized in ethylene glycol electrolyte containing with NH4F to prepare anodic film. The influence of anodization treatment on the oxidation behavior and mechanical properties of the anodized TiAl alloy were then characterized. Results shown that based on the halogen effect a continuous and dense Al2O3 oxide scale will generate on the anodized TiAl alloy after high temperature oxidation. After oxidation at 1000 ℃ for 100 h, the weight gain of the anodized TiAl alloy was dramatically decreased from 85.86 mg/cm2 to 0.67 mg/cm2. Moreover, it is shown that the surface hardness and elastic modulus of the anodized TiAl alloy decreased first and then increased with the prolonging of oxidation time. Meanwhile, the friction coefficient of the anodized TiAl alloy increased comparing to the bare TiAl alloy. The surface wear resistance of the anodized TiAl alloy exhibited similar phenomena. This is because that during high temperature oxidation process, aluminum fluorides selectively transport to the surface through pores or micro-cracks, and are oxidized to Al2O3 at the surface region. The influence of anodization treatment on the mechanical properties of the anodized TiAl alloy is attributed to the Al2O3 content contained in the oxide scale.
TiAl alloy was electrochemically anodized in ethylene glycol electrolyte containing with NH4F to prepare anodic film. The influence of anodization treatment on the oxidation behavior and mechanical properties of the anodized TiAl alloy were then characterized. Results shown that based on the halogen effect a continuous and dense Al2O3 oxide scale will generate on the anodized TiAl alloy after high temperature oxidation. After oxidation at 1000 ℃ for 100 h, the weight gain of the anodized TiAl alloy was dramatically decreased from 85.86 mg/cm2 to 0.67 mg/cm2. Moreover, it is shown that the surface hardness and elastic modulus of the anodized TiAl alloy decreased first and then increased with the prolonging of oxidation time. Meanwhile, the friction coefficient of the anodized TiAl alloy increased comparing to the bare TiAl alloy. The surface wear resistance of the anodized TiAl alloy exhibited similar phenomena. This is because that during high temperature oxidation process, aluminum fluorides selectively transport to the surface through pores or micro-cracks, and are oxidized to Al2O3 at the surface region. The influence of anodization treatment on the mechanical properties of the anodized TiAl alloy is attributed to the Al2O3 content contained in the oxide scale.
2021, 41(2): 82 -88
doi: 10.11868/j.issn.1005-5053.2020.000081
Abstract:
SiCf/SiC composites with the polycarbosilane and silicon carbide fiber of different pyrolytic carbon (PyC) interphase thicknesses as the reinforcement phase were fabricated by a polymer impregnation and pyrolysis (PIP) method. And SiC whisker was introduced into the SiCf/SiC composites to further improve its performance. It is found that the mechanical properties of SiCf/SiC composites have outstanding tensile strength, fracture toughness and flexural strength of 192.3 MPa, 446.9 MPa and 11.4 MPa·m1/2,, when the PyC interphase thickness is about 230 nm. After the introduction of SiC whisker, into the SiCf/SiC composite matrix, the toughening mechanisms such as whisker pull-out, whisker bridging and crack deflection increase the energy consumption when the crack is transferred in the matrix, and the fracture toughness and bending strength of the composite are increased by 22.9% and 9.1% respectively.
SiCf/SiC composites with the polycarbosilane and silicon carbide fiber of different pyrolytic carbon (PyC) interphase thicknesses as the reinforcement phase were fabricated by a polymer impregnation and pyrolysis (PIP) method. And SiC whisker was introduced into the SiCf/SiC composites to further improve its performance. It is found that the mechanical properties of SiCf/SiC composites have outstanding tensile strength, fracture toughness and flexural strength of 192.3 MPa, 446.9 MPa and 11.4 MPa·m1/2,, when the PyC interphase thickness is about 230 nm. After the introduction of SiC whisker, into the SiCf/SiC composite matrix, the toughening mechanisms such as whisker pull-out, whisker bridging and crack deflection increase the energy consumption when the crack is transferred in the matrix, and the fracture toughness and bending strength of the composite are increased by 22.9% and 9.1% respectively.
2021, 41(2): 89 -97
doi: 10.11868/j.issn.1005-5053.2020.000185
Abstract:
In this paper, nano-sized Gd2SiO5 powder was synthesized by a cocurrent chemical co-precipitation method with Gd2O3 and TEOS as raw materials. The thermal behavior of precursor, phase composition and microstructure of the obtained powder were investigated, the synthesis mechanism was also discussed. The results show that lower Gd: Si molar ratio in precursor and higher pH value in reaction system can lead to the formation of Gd9.33(SiO4)6O2 phase. On the contrary, Gd2O3 impurity is formed in the obtained Gd2SiO5 powder. In this study, the relatively pure Gd2SiO5 powder can be synthesized at 1000-1300 ℃ with Gd/Si molar ratio as 20: 11 and pH value in the range of 9-10. The obtained powder inhibits irregular morphology with average grain size of 100-200 nm. During the synthesis process, the precursor is generated in the form of —[Si—O—Gd]— network, and then translated to Gd2SiO5 grains, as well as Gd9.33(SiO4)6O2 and Gd2O3 impurities.
In this paper, nano-sized Gd2SiO5 powder was synthesized by a cocurrent chemical co-precipitation method with Gd2O3 and TEOS as raw materials. The thermal behavior of precursor, phase composition and microstructure of the obtained powder were investigated, the synthesis mechanism was also discussed. The results show that lower Gd: Si molar ratio in precursor and higher pH value in reaction system can lead to the formation of Gd9.33(SiO4)6O2 phase. On the contrary, Gd2O3 impurity is formed in the obtained Gd2SiO5 powder. In this study, the relatively pure Gd2SiO5 powder can be synthesized at 1000-1300 ℃ with Gd/Si molar ratio as 20: 11 and pH value in the range of 9-10. The obtained powder inhibits irregular morphology with average grain size of 100-200 nm. During the synthesis process, the precursor is generated in the form of —[Si—O—Gd]— network, and then translated to Gd2SiO5 grains, as well as Gd9.33(SiO4)6O2 and Gd2O3 impurities.
2021, 41(2): 98 -104
doi: 10.11868/j.issn.1005-5053.2019.000169
Abstract:
Viscosity is the main rheology parameter of thermosetting resin matrix processing, which is an important factor effecting processing performance. The viscosity-temperature curves at dynamic states and viscosity-time curves at stead state were measured by cone-plate rotate viscosimeter, and the rheology property of bio-based resin system based on rosin-sourced anhydride curing agent was studied according to the optimization improved six parameter dual-arrhenius equation. Two kinds of rheology models were established by fitting reaction rate constant K and pre-exponential factor A according to the exponential or logarithm viscosity relative equation, respectively. The rheology model based on logarithm viscosity relative equation simulation was in good agreement with experimental data than exponential viscosity relative equation fitting. The rheology model demonstrated the law of viscosity change at different processing conditions, which provided necessary scientific basis for processing parameter optimization.
Viscosity is the main rheology parameter of thermosetting resin matrix processing, which is an important factor effecting processing performance. The viscosity-temperature curves at dynamic states and viscosity-time curves at stead state were measured by cone-plate rotate viscosimeter, and the rheology property of bio-based resin system based on rosin-sourced anhydride curing agent was studied according to the optimization improved six parameter dual-arrhenius equation. Two kinds of rheology models were established by fitting reaction rate constant K and pre-exponential factor A according to the exponential or logarithm viscosity relative equation, respectively. The rheology model based on logarithm viscosity relative equation simulation was in good agreement with experimental data than exponential viscosity relative equation fitting. The rheology model demonstrated the law of viscosity change at different processing conditions, which provided necessary scientific basis for processing parameter optimization.
1998, 18(4): 52-61
2006, 26(3): 283-288
2000, 20(2): 55-63
2000, 20(1): 55-61
2002, 22(2): 49-53
2006, 26(3): 148-151
2009, 29(1): 1-6
2010, 30(4): 92-96
2006, 26(3): 244-250
2000, 20(3): 172-177
2001, 21(1): 55-62
2006, 26(3): 226-232
2006, 26(3): 238-243
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Copyright © 2015 Editorial Board of Journal of Aeronautical Materials
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京ICP备15058934号-1
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