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1Research Progress and Application Perspectives of 4D Printing
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2Progress on Self-Healing and Structure-Wave Absorbing Integration of Silicon Carbide Ceramic Matrix Composites
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3Research Progress of Laser Shock Treatment in the Field of Material Forming
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4Effect of Mo content on Microstructure and Mechanical Properties of IN718 Alloy
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5Effect of Rare Earth Y on Microstructure and Properties of Sn-58Bi Solder Alloy
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6Research Progress in Preparation and Crystallization Technologies of Amorphous ITO Film
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7Novel Ceramic Materials for Thermal Barrier Coatings
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8Research Process in Plasma Spray Physical Vapor Deposited Thermal Barrier Coatings
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9Research Progress on Preforms of C/C Composites
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102018-04-Catalog
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11Research Progress in Cemented Carbide with Co-Ni-Al Composite Binder Phase
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12Application and Research Status of Alternative Materials for 3D-printing Technology
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13Research Progress of Metal-Intermetallic Laminated Composites
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14Assessing delamination initiation of laminates based on bridging model
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15Thermal post-buckling behavior of ceramic-based FGM circular plates with linear variable thickness
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16Application Potential of 4D Printing Technology in Development of Aircraft
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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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52018-02-Catalog
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6Progress in Amorphous Transparent Conducting Oxide Thin Films
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7Research Progress in Preparation and Crystallization Technologies of Amorphous ITO Film
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8Current Study and Novel Ideas on Magnesium Matrix Composites
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9Research Progress in Cemented Carbide with Co-Ni-Al Composite Binder Phase
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10High Temperature Titanium Alloys：Status and Perspective
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112018-04-Catalog
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12Research Progress on Deployable Structures of Shape Memory Polymer Composites
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13Research and Application Progress of Silicone Rubber Materials in Aviation
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14Research Progress and Application Perspectives of 4D Printing
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15Failure and Protection of Thermal Barrier Coating under CMAS Attack
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16Progress on Self-Healing and Structure-Wave Absorbing Integration of Silicon Carbide Ceramic Matrix Composites
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Available online
, doi: 10.11868/j.issn.1005-5053.2018.00010
Abstract:
Numerical simulation was used to study the influence of the diameter and riser structure of rod castings on the shrinkage porosity of TiAl alloy rod castings by centrifugal casting. The reasons for the influence were analyzed according to the filling and solidification temperature fields. The results indicate that the diameter of rod castings is increased from 16 mm to 20 mm, the diameter of the entrance area is further designed into 20 mm, and the diameter of the distal end is 16 mm, the tendency for blocking the rod casting filler channel is gradually reduced, the temperature of the molten metal for feeding is increased, and the solidification time is gradually increased. Thus the feeding effect is increased, and the level of shrinkage porosity is gradually reduced. Based on the conical design of rod castings, compared with the rod castings without risers, the added ring-shaped riser causes the sequential solidification tendency of the molten metal during filling weakened, the temperature of the molten metal for feeding during solidification decreased, and the solidification time shortened. Thus the feeding effect is decreased, and the level of shrinkage porosity is slightly increased. With adding the cone-shaped riser, the sequential solidification tendency of the molten metal during filling is enhanced, the temperature of the molten metal for feeding during solidification is increased, and the solidification time is increased. Thus the feeding effect is improved, and the level of shrinkage porosity is decreased. The pouring test of the casting is carried out with the best design. The average value of the maximum shrinkage porosity of the section of rod castings is basically the same as that of the simulation test.
Numerical simulation was used to study the influence of the diameter and riser structure of rod castings on the shrinkage porosity of TiAl alloy rod castings by centrifugal casting. The reasons for the influence were analyzed according to the filling and solidification temperature fields. The results indicate that the diameter of rod castings is increased from 16 mm to 20 mm, the diameter of the entrance area is further designed into 20 mm, and the diameter of the distal end is 16 mm, the tendency for blocking the rod casting filler channel is gradually reduced, the temperature of the molten metal for feeding is increased, and the solidification time is gradually increased. Thus the feeding effect is increased, and the level of shrinkage porosity is gradually reduced. Based on the conical design of rod castings, compared with the rod castings without risers, the added ring-shaped riser causes the sequential solidification tendency of the molten metal during filling weakened, the temperature of the molten metal for feeding during solidification decreased, and the solidification time shortened. Thus the feeding effect is decreased, and the level of shrinkage porosity is slightly increased. With adding the cone-shaped riser, the sequential solidification tendency of the molten metal during filling is enhanced, the temperature of the molten metal for feeding during solidification is increased, and the solidification time is increased. Thus the feeding effect is improved, and the level of shrinkage porosity is decreased. The pouring test of the casting is carried out with the best design. The average value of the maximum shrinkage porosity of the section of rod castings is basically the same as that of the simulation test.
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Available online
, doi: 10.11868/j.issn.1005-5053.2018.000103
Abstract:
The high temperature hot deformation behavior of TB17 titanium alloy was studied using Gleeble-3800 thermo-compression simulation tester at the temperature of 860 -980 ℃, strain rate of 0.001-1 s–1 and the deformation degree of 0.7. The deformation behavior and microstructure were studied. By building the relationship between material parameters and true strain, the relationship between flow stress and deformation temperature, strain rate and strain was established by using Arrhenious constitutive equation and Z parameter. The results show that TB17 titanium alloy is more likely to happen continuous dynamic recrystallization at strain rate of 0.001-0.01 s–1 and deformation temperature of 890–980 ℃, while discontinuous dynamic recrystallization occur mainly at high strain rate (≥ 0.1 s–1).The error analysis shows that the average relative error between calculated and measured values is 6. It indicates that the constitutive relation model has higher accuracy.
The high temperature hot deformation behavior of TB17 titanium alloy was studied using Gleeble-3800 thermo-compression simulation tester at the temperature of 860 -980 ℃, strain rate of 0.001-1 s–1 and the deformation degree of 0.7. The deformation behavior and microstructure were studied. By building the relationship between material parameters and true strain, the relationship between flow stress and deformation temperature, strain rate and strain was established by using Arrhenious constitutive equation and Z parameter. The results show that TB17 titanium alloy is more likely to happen continuous dynamic recrystallization at strain rate of 0.001-0.01 s–1 and deformation temperature of 890–980 ℃, while discontinuous dynamic recrystallization occur mainly at high strain rate (≥ 0.1 s–1).The error analysis shows that the average relative error between calculated and measured values is 6. It indicates that the constitutive relation model has higher accuracy.
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Available online
, doi: 10.11868/j.issn.1005-5053.2018.000132
Abstract:
Chemical vapor deposition (CVD) is a new technology for preparing inorganic materials which possess some advantages, such as lower preparation temperature, uniform and compact microstructure, and near-size molding, so it is a prefer method to prepare functional ceramics. In the paper, several common chemical vapor deposition methods like atmospheric chemical vapor deposition, low-pressure chemical vapor deposition, plasma-enhanced chemical vapor deposition and laser-assisted chemical vapor deposition are reviewed, because the microstructure and performance of functional ceramics are greatly influenced by their fabrication methods. In addition, the deposition parameters of Si-C-N absorbing ceramics which were deposited at lower temperature by low-pressure chemical vapor deposition were optimized. It is proposed that low-pressure chemical vapor deposition is the main method for preparing advanced EMW absorbing ceramics.
Chemical vapor deposition (CVD) is a new technology for preparing inorganic materials which possess some advantages, such as lower preparation temperature, uniform and compact microstructure, and near-size molding, so it is a prefer method to prepare functional ceramics. In the paper, several common chemical vapor deposition methods like atmospheric chemical vapor deposition, low-pressure chemical vapor deposition, plasma-enhanced chemical vapor deposition and laser-assisted chemical vapor deposition are reviewed, because the microstructure and performance of functional ceramics are greatly influenced by their fabrication methods. In addition, the deposition parameters of Si-C-N absorbing ceramics which were deposited at lower temperature by low-pressure chemical vapor deposition were optimized. It is proposed that low-pressure chemical vapor deposition is the main method for preparing advanced EMW absorbing ceramics.
Experiment and simulation of the thermo-mechanical coupled behavior of SMA under low velocity impact
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Available online
, doi: 10.11868/j.issn.1005-5053.2018.000136
Abstract:
The thermomechanical coupled behavior of Shape Memory Alloy (SMA) plate under low velocity impact loading is investigated. The impact tests of SMA plate under different impact energies are carried out by a falling weight impactor. During the test, the thermodynamic phenomenon is recorded by the force sensor and the thermal imaging device. Based on the SMA thermomechanical constitutive model, the impact response of SMA plate is numerically simulated in Abaqus/Explicit. The numerical simulation results are in good agreement with the experimental data, which effectively characterizes the thermomechanical coupled behavior such as deformation, phase transformation, dissipation and temperature change during the impact of SMA plates.
The thermomechanical coupled behavior of Shape Memory Alloy (SMA) plate under low velocity impact loading is investigated. The impact tests of SMA plate under different impact energies are carried out by a falling weight impactor. During the test, the thermodynamic phenomenon is recorded by the force sensor and the thermal imaging device. Based on the SMA thermomechanical constitutive model, the impact response of SMA plate is numerically simulated in Abaqus/Explicit. The numerical simulation results are in good agreement with the experimental data, which effectively characterizes the thermomechanical coupled behavior such as deformation, phase transformation, dissipation and temperature change during the impact of SMA plates.
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Available online
, doi: 10.11868/j.issn.1005-5053.2018.000092
Abstract:
The effect of micro phase morphology of bismaleimide (BMI)/polyethersulfone (PES) multi-phase systems on the thermal properties were studied by SEM、DMA and TGA. The SEM results suggest that the phase separation exists in the multi-phase BMI/PES resin. Phase inversion happens with the addition of PES up to 15 phr. SEM shows subtle micro structure with fine BMI-rich particulate phases surrounded by continuous PES-rich phase. The glass transition temperature (Tg) belonging to BMI-rich phase of BMI/PES resin is higher than neat BMI resin. BMI/PES-5 resin system exhibits only one Tg and the temperature corresponding to the decrease of initial modulus increased. Such will be reduced. The high-temperature plastic behavior of BMI/PES resin system is enhanced with the increase of PES. The peak thermal decomposition temperature and char yield of BMI/PES resin are enhanced owing to the excellent interface interaction between BMI and PES as well as the thermal protection effect of PES. The heat resistance of resin systems under N2 atmosphere are superior to systems under air atmosphere.
The effect of micro phase morphology of bismaleimide (BMI)/polyethersulfone (PES) multi-phase systems on the thermal properties were studied by SEM、DMA and TGA. The SEM results suggest that the phase separation exists in the multi-phase BMI/PES resin. Phase inversion happens with the addition of PES up to 15 phr. SEM shows subtle micro structure with fine BMI-rich particulate phases surrounded by continuous PES-rich phase. The glass transition temperature (Tg) belonging to BMI-rich phase of BMI/PES resin is higher than neat BMI resin. BMI/PES-5 resin system exhibits only one Tg and the temperature corresponding to the decrease of initial modulus increased. Such will be reduced. The high-temperature plastic behavior of BMI/PES resin system is enhanced with the increase of PES. The peak thermal decomposition temperature and char yield of BMI/PES resin are enhanced owing to the excellent interface interaction between BMI and PES as well as the thermal protection effect of PES. The heat resistance of resin systems under N2 atmosphere are superior to systems under air atmosphere.
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Available online
, doi: 10.11868/j.issn.1005-5053.2019.000013
Abstract:
A poly (methylphenyl silylene aryl ether arylacetylene) (PSEA-P2) resin was synthesized from 1, 4-bis (4’-ethynylphenoxy) benzene and methylphenyldichlorosilane through Grignard reaction. The carbon fiber reinforced PSEA-P2 resin composite was also prepared. The structure of the resin was characterized by proton nuclear magnetic resonance and Fourier transform infrared spectroscopy. The thermal behaviour of the resin was examined by differential scanning calorimetry. The glass transition temperature and heat resistance of PSEA-P2 resin were examined by dynamic thermomechanical analysis and thermogravimetric analysis respectively. The results show that the glass transition temperature and the degradation temperature in N2 are higher than 450 ℃ and 531 ℃ respectively. The processing performance was determined by rotational rheological analysis. The results show that the processing window of PSEA-P2 resin is in the temperature range of 110-175 ℃, which is suitable for compression molding. The cured resin has excellent mechanical strength and heat resistance. The flexural strength of the cured resin is 54.3 MPa. The flexural strength of T300 carbon fiber reinforced composite can reach 518.0 MPa at room temperature, and its retention rate at 400 ℃ is 53%. The good mechanical strength of PSEA-P2 resin is due to the polar aryl ether bonds in molecular chain which enhances the bonding force between the resin and the fiber. On the other hand, the degree of crosslinking after curing is appropriate which reduces the decrease of mechanical properties caused by excessively high degree of crosslinking.
A poly (methylphenyl silylene aryl ether arylacetylene) (PSEA-P2) resin was synthesized from 1, 4-bis (4’-ethynylphenoxy) benzene and methylphenyldichlorosilane through Grignard reaction. The carbon fiber reinforced PSEA-P2 resin composite was also prepared. The structure of the resin was characterized by proton nuclear magnetic resonance and Fourier transform infrared spectroscopy. The thermal behaviour of the resin was examined by differential scanning calorimetry. The glass transition temperature and heat resistance of PSEA-P2 resin were examined by dynamic thermomechanical analysis and thermogravimetric analysis respectively. The results show that the glass transition temperature and the degradation temperature in N2 are higher than 450 ℃ and 531 ℃ respectively. The processing performance was determined by rotational rheological analysis. The results show that the processing window of PSEA-P2 resin is in the temperature range of 110-175 ℃, which is suitable for compression molding. The cured resin has excellent mechanical strength and heat resistance. The flexural strength of the cured resin is 54.3 MPa. The flexural strength of T300 carbon fiber reinforced composite can reach 518.0 MPa at room temperature, and its retention rate at 400 ℃ is 53%. The good mechanical strength of PSEA-P2 resin is due to the polar aryl ether bonds in molecular chain which enhances the bonding force between the resin and the fiber. On the other hand, the degree of crosslinking after curing is appropriate which reduces the decrease of mechanical properties caused by excessively high degree of crosslinking.
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Available online
, doi: 10.11868/j.issn.1005-5053.2018.000137
Abstract:
Celsian was synthesized in situ and was used to sinter silicon carbide. The low temperature pressureless liquid sintering process for BAS/SiC complex phase ceramics was studied, and ceramic materials with high density were prepared. The effect of sintering temperature and content of BAS on density, structure and mechanical properties of the ceramics were investigated. The densification and microstructures of BAS/SiC ceramics were observed by scanning electron microscope. The crystalline phase of the complex ceramics was identified by X-ray powder diffraction. The results show that celsian is synthesized at the temperature of 1800 ℃, and BAS/SiC ceramics are prepared with density of 3.2 g/cm3. BAS is precipitated in hexagonal structure, and SiC particles are distributed uniformly in the complex ceramic. The flexural strength and fracture toughness of complex ceramics are decreased due to grains growth while the sintering temperature is above 1800 ℃. When the mass content of BAS reaches 30%, the typical flexural strength, elastic modulus and fracture toughness of the pressureless sintered BAS/SiC ceramics are 413 MPa, 210 GPa and 5.03 MPa·m1/2 at room temperature.
Celsian was synthesized in situ and was used to sinter silicon carbide. The low temperature pressureless liquid sintering process for BAS/SiC complex phase ceramics was studied, and ceramic materials with high density were prepared. The effect of sintering temperature and content of BAS on density, structure and mechanical properties of the ceramics were investigated. The densification and microstructures of BAS/SiC ceramics were observed by scanning electron microscope. The crystalline phase of the complex ceramics was identified by X-ray powder diffraction. The results show that celsian is synthesized at the temperature of 1800 ℃, and BAS/SiC ceramics are prepared with density of 3.2 g/cm3. BAS is precipitated in hexagonal structure, and SiC particles are distributed uniformly in the complex ceramic. The flexural strength and fracture toughness of complex ceramics are decreased due to grains growth while the sintering temperature is above 1800 ℃. When the mass content of BAS reaches 30%, the typical flexural strength, elastic modulus and fracture toughness of the pressureless sintered BAS/SiC ceramics are 413 MPa, 210 GPa and 5.03 MPa·m1/2 at room temperature.
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Available online
, doi: 10.11868/j.issn.1005-5053.2018.000086
Abstract:
By means of microstructure observation on Hf-containing K416B Ni-based superalloy with high W-content after solid solution heat treatment at different temperatures, the effect of solid solution temperature on microstructure of the alloy was investigated. The results show that with the increasing of solid solution temperature, the size of secondary dendrite increases slightly by element diffusion, and the eutectic content decreases gradually to promote the densification of alloy microstructure. In addition, the γ′ phase is dissolved into the matrix, and its size is decreased. During high temperature solid solution heat treatment, the primary strip MC phase in the inter-dendrite is decomposed to form granular M6C carbides, while the morphology and quantity of large sized block M6C phase in eutectic have no obvious change. The solid solution treatment causes that the element W is segregated in the dendrites to diffuse into inter-dendrites, and elements of Hf, Nb, Ti and Cr diffuse into the dendrites, the segregation degree of each element of the alloy is greatly reduced. The results of microstructure research indicate that the optimal solid-solution heat treatment process for the alloy is 1220 ℃ × 4 h.
By means of microstructure observation on Hf-containing K416B Ni-based superalloy with high W-content after solid solution heat treatment at different temperatures, the effect of solid solution temperature on microstructure of the alloy was investigated. The results show that with the increasing of solid solution temperature, the size of secondary dendrite increases slightly by element diffusion, and the eutectic content decreases gradually to promote the densification of alloy microstructure. In addition, the γ′ phase is dissolved into the matrix, and its size is decreased. During high temperature solid solution heat treatment, the primary strip MC phase in the inter-dendrite is decomposed to form granular M6C carbides, while the morphology and quantity of large sized block M6C phase in eutectic have no obvious change. The solid solution treatment causes that the element W is segregated in the dendrites to diffuse into inter-dendrites, and elements of Hf, Nb, Ti and Cr diffuse into the dendrites, the segregation degree of each element of the alloy is greatly reduced. The results of microstructure research indicate that the optimal solid-solution heat treatment process for the alloy is 1220 ℃ × 4 h.
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2019, 39(2): 1 -9
doi: 10.11868/j.issn.1005-5053.2018.000041
Abstract:
4D Printing technology can achieve additive manufacturing of smart materials. Recent progresses of 4D printing composite materials, shape memory polymers, shape memory alloys and other smart materials were reviewed. 4D printing technology is developing towards multi-material precise compounding, fast response and functional forming materials recently. 4D printing technology of shape memory polymers is developing towards shape controllable and accurate movement. 4D printing technology of shape memory alloys is developing towards precise control of phase transition behavior and deformation controllable. Several considerations about 4D printing shape memory alloys were proposed based on unsolved problems, such as: the factors should be considered for obtaining near-full dense 4D printed shape memory alloys, effect of voids on its comprehensive properties, regulation of structure and properties, and deformation control, etc. Overall, with the development of new materials, forming methods, control software and machine accuracy, 4D printing technology is developed rapidly, and is gradually moving towards intellectualization, accuracy and efficiency.
4D Printing technology can achieve additive manufacturing of smart materials. Recent progresses of 4D printing composite materials, shape memory polymers, shape memory alloys and other smart materials were reviewed. 4D printing technology is developing towards multi-material precise compounding, fast response and functional forming materials recently. 4D printing technology of shape memory polymers is developing towards shape controllable and accurate movement. 4D printing technology of shape memory alloys is developing towards precise control of phase transition behavior and deformation controllable. Several considerations about 4D printing shape memory alloys were proposed based on unsolved problems, such as: the factors should be considered for obtaining near-full dense 4D printed shape memory alloys, effect of voids on its comprehensive properties, regulation of structure and properties, and deformation control, etc. Overall, with the development of new materials, forming methods, control software and machine accuracy, 4D printing technology is developed rapidly, and is gradually moving towards intellectualization, accuracy and efficiency.
2019, 39(2): 10 -15
doi: 10.11868/j.issn.1005-5053.2018.000088
Abstract:
Selective laser sintering (SLS) was adopted to rapidly prepare silica-based ceramic shell for superalloy turbine blade, and combined with high-temperature sintering process to further improve the mechanical properties of ceramic shell. The effects of different sintering temperatures (1450~1600 ℃) on the flexural strength of alumina-based ceramic shells were investigated. The phase constitution and fracture morphology of alumina-based ceramic shell molds were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that ceramic shell with excellent mechanical properties can be obtained by SLS+high-temperature sintering quickly and effectively. As sintering temperature increases from 1450 ℃ to 1600 ℃, flexural strength of ceramic shell at room temperature increases, and reaches 38.03 MPa at 1600 ℃. Columnar mullite phase is the main strengthening phase, with the increase of sintering temperature, the content of mullite phase in the shell increases, the content of quartz phase decreases, and the content of cristobalite phase increases first and then decreases. The crack propagation form changes from slow expansion to rapid expansion and causes transient fracture. The fracture changes from a tearing shape to a flush small section, and appear the intergranular and transgranular fracture mode, the crack is tended to expand to the mullite particles.
Selective laser sintering (SLS) was adopted to rapidly prepare silica-based ceramic shell for superalloy turbine blade, and combined with high-temperature sintering process to further improve the mechanical properties of ceramic shell. The effects of different sintering temperatures (1450~1600 ℃) on the flexural strength of alumina-based ceramic shells were investigated. The phase constitution and fracture morphology of alumina-based ceramic shell molds were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that ceramic shell with excellent mechanical properties can be obtained by SLS+high-temperature sintering quickly and effectively. As sintering temperature increases from 1450 ℃ to 1600 ℃, flexural strength of ceramic shell at room temperature increases, and reaches 38.03 MPa at 1600 ℃. Columnar mullite phase is the main strengthening phase, with the increase of sintering temperature, the content of mullite phase in the shell increases, the content of quartz phase decreases, and the content of cristobalite phase increases first and then decreases. The crack propagation form changes from slow expansion to rapid expansion and causes transient fracture. The fracture changes from a tearing shape to a flush small section, and appear the intergranular and transgranular fracture mode, the crack is tended to expand to the mullite particles.
2019, 39(2): 16 -24
doi: 10.11868/j.issn.1005-5053.2018.000060
Abstract:
The influence of the process parameters of SiC ceramics on the processing quality was discussed. The corrosion mechanism of SiC ceramics was analyzed. The corrosion rate and porosity of samples were measured by the method of weight-loss and Archimedes respectively. The surface morphology and structure of the specimen were characterized by XRD, SEM and roughness tester. The results show that the corrosion rate increases with the increase of temperature and KOH concentration, and the corrosion effect is significantly improved when the temperature is higher than the boiling point of the alkali solution. The high concentration of alkali solution causes the porosity to decrease, and the increase of temperature can slow down the decrease of porosity. Under the optimized process parameters, the high temperature chemical corrosion can reduce the roughness of the sample, and the minimum roughness(Ra) of the surface is 1.6 μm. The surface quality is improved, the length of contour support is increased, and Rmr (50%) reaches 89.70%. The excessive corrosion temperature or too long time causes the grains to fall off, resulting in a sharp drop of surface quality. In addition, compared with the machining samples, no cracks are found on the sample of high temperature chemical processing. After simple cleaning, the surface has no reactant residue.
The influence of the process parameters of SiC ceramics on the processing quality was discussed. The corrosion mechanism of SiC ceramics was analyzed. The corrosion rate and porosity of samples were measured by the method of weight-loss and Archimedes respectively. The surface morphology and structure of the specimen were characterized by XRD, SEM and roughness tester. The results show that the corrosion rate increases with the increase of temperature and KOH concentration, and the corrosion effect is significantly improved when the temperature is higher than the boiling point of the alkali solution. The high concentration of alkali solution causes the porosity to decrease, and the increase of temperature can slow down the decrease of porosity. Under the optimized process parameters, the high temperature chemical corrosion can reduce the roughness of the sample, and the minimum roughness(Ra) of the surface is 1.6 μm. The surface quality is improved, the length of contour support is increased, and Rmr (50%) reaches 89.70%. The excessive corrosion temperature or too long time causes the grains to fall off, resulting in a sharp drop of surface quality. In addition, compared with the machining samples, no cracks are found on the sample of high temperature chemical processing. After simple cleaning, the surface has no reactant residue.
2019, 39(2): 25 -32
doi: 10.11868/j.issn.1005-5053.2018.000142
Abstract:
Graphene oxide (GO) modified epoxy resin (GH81) was prepared by mechanical grinding, and the dispersion of GO in the epoxy resin (H81) was analyzed by optical microscope, while the melting performances and curing behaviors of H81 and GH81 were researched through rheometer and differential scanning calorimeter respectively. The results show that GO is uniformly dispersed into the matrix resin, and the addition of GO hardly affects the melt viscosity and curing condition of the matrix resin at all. In addition, the 0° tensile strength, bending strength and compression strength of GH81 based carbon fiber reinforced composite (GH81-300) are 2270 MPa, 2239 MPa and 1529 MPa respectively, which is increased by 6.4%, 7.2% and 7.1% respectively, as compared with that of composite without GO.
Graphene oxide (GO) modified epoxy resin (GH81) was prepared by mechanical grinding, and the dispersion of GO in the epoxy resin (H81) was analyzed by optical microscope, while the melting performances and curing behaviors of H81 and GH81 were researched through rheometer and differential scanning calorimeter respectively. The results show that GO is uniformly dispersed into the matrix resin, and the addition of GO hardly affects the melt viscosity and curing condition of the matrix resin at all. In addition, the 0° tensile strength, bending strength and compression strength of GH81 based carbon fiber reinforced composite (GH81-300) are 2270 MPa, 2239 MPa and 1529 MPa respectively, which is increased by 6.4%, 7.2% and 7.1% respectively, as compared with that of composite without GO.
2019, 39(2): 33 -41
doi: 10.11868/j.issn.1005-5053.2018.000141
Abstract:
This study aims to evaluate the FGH96 superalloy joints fabricated by inertia friction welding (IFW) in different welding parameters, such as initial rotational speed and axial friction pressure, where the moment of inertia remained constant. The microstructure and the width of the weld nugget zone (WNZ) were analyzed, and tensile property of joints was examined. The effect of welding parameters on high temperature tensile property of FGH96 joints was investigated. The results show that the joint presents a significant microstructure change across the faying interface, characterized by the very small uniform equiaxed grains of WNZ, coarse and fine grain coexistence of the thermo-mechanically affected zone (TMAZ). As the rotation speed increases, the tensile property remains constant. However, with increasing friction pressure, they show a substantial increase.The change tendency of the width of WNZ with welding parameters is in agreement with that of tensile property, which is related to the weld heat input and the plastic flow of the material. The high temperature tensile specimens are fractured in the WNZ. This is related to the complete γ′-phase dissolution which softens the joint and decreases the joint tensile property. Therefore, the post-weld heat treatments are necessary for IFW FGH96 superalloy in order to further improve the joint properties.
This study aims to evaluate the FGH96 superalloy joints fabricated by inertia friction welding (IFW) in different welding parameters, such as initial rotational speed and axial friction pressure, where the moment of inertia remained constant. The microstructure and the width of the weld nugget zone (WNZ) were analyzed, and tensile property of joints was examined. The effect of welding parameters on high temperature tensile property of FGH96 joints was investigated. The results show that the joint presents a significant microstructure change across the faying interface, characterized by the very small uniform equiaxed grains of WNZ, coarse and fine grain coexistence of the thermo-mechanically affected zone (TMAZ). As the rotation speed increases, the tensile property remains constant. However, with increasing friction pressure, they show a substantial increase.The change tendency of the width of WNZ with welding parameters is in agreement with that of tensile property, which is related to the weld heat input and the plastic flow of the material. The high temperature tensile specimens are fractured in the WNZ. This is related to the complete γ′-phase dissolution which softens the joint and decreases the joint tensile property. Therefore, the post-weld heat treatments are necessary for IFW FGH96 superalloy in order to further improve the joint properties.
2019, 39(2): 42 -48
doi: 10.11868/j.issn.1005-5053.2018.000115
Abstract:
Ni-graphite abradable seal coatings were deposited by conventional atmospheric plasma spraying system (APS) and high efficiency supersonic atmospheric plasma spraying system (SAPS) respectively. The influence of the size of lubrication phase on mechanical properties, corrosion resistance and erosion resistance of the Ni-graphite coatings was investigated. The results indicate that the graphite phase in the SAPS coating has a smaller size than the APS coating. The bonding strength (21.0 ± 1.4) MPa and surface hardness (92 ± 1) HR15Y of SAPS coating are 29.6 % and 23.5 % higher than those of APS coating respectively. The relative erosion rates of APS coating at 30° and 90° angle of attack are 7 % and 13% higher than those of SAPS coating respectively, indicating that SAPS coating has a better erosion resistance than APS coating. Both APS coating and SAPS coating exhibit an obvious electrochemical corrosion in acetic acid environment at 250 ℃．However, the corrosion resistance of SAPS coating is better than that of APS coating.
Ni-graphite abradable seal coatings were deposited by conventional atmospheric plasma spraying system (APS) and high efficiency supersonic atmospheric plasma spraying system (SAPS) respectively. The influence of the size of lubrication phase on mechanical properties, corrosion resistance and erosion resistance of the Ni-graphite coatings was investigated. The results indicate that the graphite phase in the SAPS coating has a smaller size than the APS coating. The bonding strength (21.0 ± 1.4) MPa and surface hardness (92 ± 1) HR15Y of SAPS coating are 29.6 % and 23.5 % higher than those of APS coating respectively. The relative erosion rates of APS coating at 30° and 90° angle of attack are 7 % and 13% higher than those of SAPS coating respectively, indicating that SAPS coating has a better erosion resistance than APS coating. Both APS coating and SAPS coating exhibit an obvious electrochemical corrosion in acetic acid environment at 250 ℃．However, the corrosion resistance of SAPS coating is better than that of APS coating.
2019, 39(2): 49 -54
doi: 10.11868/j.issn.1005-5053.2018.000111
Abstract:
NiO, Er2O3, Yb2O3, Y2O3 and ZrO2 powders were used as raw materials to prepare composite ceramic materials by the method of high temperature solid phase synthesis. The specific heat, thermal diffusion coefficient, thermal conductivity and other thermal physical properties of the composite ceramic materials were studied and compared with the traditional 8YSZ thermal barrier coating materials. The crystal structure and phase composition were tested by XRD. The results show that after NiO, Er2O3, Yb2O3, Y2O3 and ZrO2 co-doping, the thermal diffusion coefficient is 0.36-0.56 mm2/s, which is 20% lower than that of YSZ from room temperature to 1500 ℃, the thermal conductivities is 1.45-1.55 W/(m•K), which is 18% lower than that of YSZ from room temperature to 1500 ℃, 2EYNYSZ material has single phase structure, and 1500 ℃ heat-treatment does not occur phase transition within 100 h.
NiO, Er2O3, Yb2O3, Y2O3 and ZrO2 powders were used as raw materials to prepare composite ceramic materials by the method of high temperature solid phase synthesis. The specific heat, thermal diffusion coefficient, thermal conductivity and other thermal physical properties of the composite ceramic materials were studied and compared with the traditional 8YSZ thermal barrier coating materials. The crystal structure and phase composition were tested by XRD. The results show that after NiO, Er2O3, Yb2O3, Y2O3 and ZrO2 co-doping, the thermal diffusion coefficient is 0.36-0.56 mm2/s, which is 20% lower than that of YSZ from room temperature to 1500 ℃, the thermal conductivities is 1.45-1.55 W/(m•K), which is 18% lower than that of YSZ from room temperature to 1500 ℃, 2EYNYSZ material has single phase structure, and 1500 ℃ heat-treatment does not occur phase transition within 100 h.
2019, 39(2): 55 -60
doi: 10.11868/j.issn.1005-5053.2018.000016
Abstract:
The resistance abilities of (100) and (111)-faceted diamond films against oxygen plasma, 100 μm as film thickness, were investigated by the microwave power chemical vapor deposition (MPCVD) technique. The results indicate that the preferred etching points of the (100)-faceted diamond films are located at the grain boundaries and the preferred etching points of the (111)-faceted diamond films are located at the crystal surfaces. After 30 minutes etching, the (100)-faceted crystal can still be obviously shown while the (111)-faceted crystal is unobvious. After 60 minutes etching, the preferential orientations of (100)-faceted and(111)-faceted diamond films both are disappeared. The FWHM value of the (100)-faceted diamond films is increased from 8.51 cm–1 to 12.48 cm–1 and the FWHM value of the(111)-faceted diamond films is increased from 8.74 cm–1 to 148.49 cm–1 when the etching time is 60 minutes. The etching rate of the (100)-faceted diamond film is 0.35 μm/min when the etching time is 40 minutes and it is increased to 1.34 μm/min when the etching time is 60 minutes. At early stage, the (100)-faceted diamond film presented better resistance ability than the (111)-faceted diamond film against the oxygen plasma etching. But the resistance abilities to the plasma etching of the (100) and the (111)-faceted diamond films are similar when the etching time is 60 minutes.
The resistance abilities of (100) and (111)-faceted diamond films against oxygen plasma, 100 μm as film thickness, were investigated by the microwave power chemical vapor deposition (MPCVD) technique. The results indicate that the preferred etching points of the (100)-faceted diamond films are located at the grain boundaries and the preferred etching points of the (111)-faceted diamond films are located at the crystal surfaces. After 30 minutes etching, the (100)-faceted crystal can still be obviously shown while the (111)-faceted crystal is unobvious. After 60 minutes etching, the preferential orientations of (100)-faceted and(111)-faceted diamond films both are disappeared. The FWHM value of the (100)-faceted diamond films is increased from 8.51 cm–1 to 12.48 cm–1 and the FWHM value of the(111)-faceted diamond films is increased from 8.74 cm–1 to 148.49 cm–1 when the etching time is 60 minutes. The etching rate of the (100)-faceted diamond film is 0.35 μm/min when the etching time is 40 minutes and it is increased to 1.34 μm/min when the etching time is 60 minutes. At early stage, the (100)-faceted diamond film presented better resistance ability than the (111)-faceted diamond film against the oxygen plasma etching. But the resistance abilities to the plasma etching of the (100) and the (111)-faceted diamond films are similar when the etching time is 60 minutes.
2019, 39(2): 61 -67
doi: 10.11868/j.issn.1005-5053.2018.000023
Abstract:
In order to study the influence of the equal-life curve models on DFR, the fitting accuracies of Gerber model and Goodman model for high-cycle fatigue data were compared with six typical aviation materials．The formula of DFR based on Gerber model and the expression of corrosion conversion coefficient CC were derived, pre-corrosion fatigue tests for 0 h, 6 h, 12 h, 24 h, 36 h, and 72 h of 2024-T3 aluminum alloy (surface anodizing) were carried out, and the fatigue fracture of pre-corrosion for 72 hours was analyzed. The results show that Goodman model is suitable for brittle materials while Gerber model is suitable for ductile materials. As the pre-corrosion time increases, the DFR of 2024-T3 aluminum alloy decreases．The DFR based on Gerber model are 84.251 MPa, 84.721 MPa, 79.683 MPa, 80.745 MPa, 77.026 MPa and 74.996 MPa respectively, and the CC is 1.006, 0.946, 0.958, 0.914 and 0.890, the fitting curve of the DFR with the pre-corrosion time is\begin{document}$ DFR=84.251{\left[ {\lg \left( {t + 10} \right)} \right]^{ - 0.15578}}$\end{document} ![]()
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In order to study the influence of the equal-life curve models on DFR, the fitting accuracies of Gerber model and Goodman model for high-cycle fatigue data were compared with six typical aviation materials．The formula of DFR based on Gerber model and the expression of corrosion conversion coefficient CC were derived, pre-corrosion fatigue tests for 0 h, 6 h, 12 h, 24 h, 36 h, and 72 h of 2024-T3 aluminum alloy (surface anodizing) were carried out, and the fatigue fracture of pre-corrosion for 72 hours was analyzed. The results show that Goodman model is suitable for brittle materials while Gerber model is suitable for ductile materials. As the pre-corrosion time increases, the DFR of 2024-T3 aluminum alloy decreases．The DFR based on Gerber model are 84.251 MPa, 84.721 MPa, 79.683 MPa, 80.745 MPa, 77.026 MPa and 74.996 MPa respectively, and the CC is 1.006, 0.946, 0.958, 0.914 and 0.890, the fitting curve of the DFR with the pre-corrosion time is
2019, 39(2): 68 -74
doi: 10.11868/j.issn.1005-5053.2018.000084
Abstract:
The material behavior of glass fiber reinforced aluminum laminates (GLARE) under low-speed impact of a falling hammer was studied, and a finite element model of ABAQUS for simulation and experimental verification was built. According to the characteristics of fiber metal matrix materials, the continuous damage mechanics (CDM) model was adopted, and the impact energy values of the falling hammer were set as 6.22 J, 12.38 J and 14.46 J respectively. The corresponding boundary conditions and loads of the model in ABAQUS were confirmed to obtain the velocity-time curve and energy loss curve of the falling direction of the falling hammer. The cohesive layer between metal layer and composite layer was taken into consideration, and the ‘Cohesive Layer’ in ABAQUS was adopted to bond metal layer and composite material layer. The tensile and compressive damage states of fibers and matrix in simulation were observed and compared with the experimental results. The results show that the finite element simulation can accurately simulate the crack and bulge effect on the back of GLARE laminates after the impact, as well as the damage situation of the matrix and fiber, so as to well predict the internal damage of the composite material.
The material behavior of glass fiber reinforced aluminum laminates (GLARE) under low-speed impact of a falling hammer was studied, and a finite element model of ABAQUS for simulation and experimental verification was built. According to the characteristics of fiber metal matrix materials, the continuous damage mechanics (CDM) model was adopted, and the impact energy values of the falling hammer were set as 6.22 J, 12.38 J and 14.46 J respectively. The corresponding boundary conditions and loads of the model in ABAQUS were confirmed to obtain the velocity-time curve and energy loss curve of the falling direction of the falling hammer. The cohesive layer between metal layer and composite layer was taken into consideration, and the ‘Cohesive Layer’ in ABAQUS was adopted to bond metal layer and composite material layer. The tensile and compressive damage states of fibers and matrix in simulation were observed and compared with the experimental results. The results show that the finite element simulation can accurately simulate the crack and bulge effect on the back of GLARE laminates after the impact, as well as the damage situation of the matrix and fiber, so as to well predict the internal damage of the composite material.
2019, 39(2): 75 -83
doi: 10.11868/j.issn.1005-5053.2018.000074
Abstract:
In order to accurately calculate the thermal response of 3D braided carbon/phenolic composite under high temperature, the matrix and fiber bundle of composite were established separately and a mathematical model was adopted based on the conservation of energy and mass, changes in phenolic matrix density as well as material thermal properties in pyrolysis process. The distributions of temperature field and pyrolysis degree were predicted, and the mass loss rate, the formation position and the thickness of char layer were shown. The results show that the temperature distribution of the 3D braided carbon/phenolic composite is extremely uneven, and the matrix temperature on the heating surface is significantly higher than the fiber bundle temperature, while the vertical fiber bundle temperature inside the material is higher than the matrix temperature. At the beginning of heating, the char layer is not generated immediately, but requires a transition period, during which the average thickness of the char layer is zero. The calculation of thermal response can better understand the behavioral characteristics of the composite, and provide reference and basis for the design and optimization of the thermal protection materials.
In order to accurately calculate the thermal response of 3D braided carbon/phenolic composite under high temperature, the matrix and fiber bundle of composite were established separately and a mathematical model was adopted based on the conservation of energy and mass, changes in phenolic matrix density as well as material thermal properties in pyrolysis process. The distributions of temperature field and pyrolysis degree were predicted, and the mass loss rate, the formation position and the thickness of char layer were shown. The results show that the temperature distribution of the 3D braided carbon/phenolic composite is extremely uneven, and the matrix temperature on the heating surface is significantly higher than the fiber bundle temperature, while the vertical fiber bundle temperature inside the material is higher than the matrix temperature. At the beginning of heating, the char layer is not generated immediately, but requires a transition period, during which the average thickness of the char layer is zero. The calculation of thermal response can better understand the behavioral characteristics of the composite, and provide reference and basis for the design and optimization of the thermal protection materials.
2019, 39(2): 84 -89
doi: 10.11868/j.issn.1005-5053.2018.000113
Abstract:
Nonlinear mechanical behaviors of functionally graded material (FGM) beams subjected to tangentially distributed loads in uniform and inhomogeneous heating fields were investigated. Based on the geometric nonlinear theory of extensible beams, the governing differential equations of functionally graded material beams under tangentially distributed loads in thermal environment were established. The nonlinear mechanical behavior of FGM beams composed of ceramic zirconia and titanium alloy was analyzed by using shooting method. The equilibrium paths and configurations of FGM beams subjected to tangentially distributed loads under different uniform and non-uniform heating conditions were given. The effects of uniform and inhomogeneous temperature rise and material gradient parameters on bending and post-buckling behavior of beams were discussed in detail. The results show that FGM beams have the bending behavior, whereas the beams with homogeneous materials exhibit post-buckling behavior in thermal environment, and the non-uniform heating has a great influence on the mechanical behavior of non-conservative beams.
Nonlinear mechanical behaviors of functionally graded material (FGM) beams subjected to tangentially distributed loads in uniform and inhomogeneous heating fields were investigated. Based on the geometric nonlinear theory of extensible beams, the governing differential equations of functionally graded material beams under tangentially distributed loads in thermal environment were established. The nonlinear mechanical behavior of FGM beams composed of ceramic zirconia and titanium alloy was analyzed by using shooting method. The equilibrium paths and configurations of FGM beams subjected to tangentially distributed loads under different uniform and non-uniform heating conditions were given. The effects of uniform and inhomogeneous temperature rise and material gradient parameters on bending and post-buckling behavior of beams were discussed in detail. The results show that FGM beams have the bending behavior, whereas the beams with homogeneous materials exhibit post-buckling behavior in thermal environment, and the non-uniform heating has a great influence on the mechanical behavior of non-conservative beams.
2019, 39(2): 90 -98
doi: 10.11868/j.issn.1005-5053.2018.000078
Abstract:
In order to solve the problems existing in airworthiness verification of the large integral metallic structure for civil aircraft main bearing part, the airworthiness verification of the metallic structure additive manufacturing technology was carried out. Through the analysis of applicable airworthiness clauses of additive manufacturing technology, the general idea of airworthiness verification of the metallic structure additive manufacturing technology of civil aircraft is given, including the establishment of material specification, the determination of material strength properties, the selection of structural special factor, and the verification of structural performance. Each verification method gives a specific implementation approach. Taking outer cylinder of the nose landing gear pillar which is made by additive manufacturing technology with A-100 ultrahigh strength steel as an example, a specific implementation plan for airworthiness verification of additive manufacturing technology for large integral metallic structure is given.
In order to solve the problems existing in airworthiness verification of the large integral metallic structure for civil aircraft main bearing part, the airworthiness verification of the metallic structure additive manufacturing technology was carried out. Through the analysis of applicable airworthiness clauses of additive manufacturing technology, the general idea of airworthiness verification of the metallic structure additive manufacturing technology of civil aircraft is given, including the establishment of material specification, the determination of material strength properties, the selection of structural special factor, and the verification of structural performance. Each verification method gives a specific implementation approach. Taking outer cylinder of the nose landing gear pillar which is made by additive manufacturing technology with A-100 ultrahigh strength steel as an example, a specific implementation plan for airworthiness verification of additive manufacturing technology for large integral metallic structure is given.
2018, 38(2): 70-76
doi: 10.11868/j.issn.1005-5053.2018.001005
2018, 38(6): 1-10
doi: 10.11868/j.issn.1005-5053.2018.000081
2018, 38(4): 64-74
doi: 10.11868/j.issn.1005-5053.2018.000025
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(2): 10-20
doi: 10.11868/j.issn.1005-5053.2018.001001
2018, 38(2): 1-9
doi: 10.11868/j.issn.1005-5053.2018.001008
2018, 38(2): 86-95
doi: 10.11868/j.issn.1005-5053.2017.000010
2018, 38(5): 47-58
doi: 10.11868/j.issn.1005-5053.2018.000022
2016, 36(4): 89-98
doi: 10.11868/j.issn.1005-5053.2016.4.013
2018, 38(4): 37-46
doi: 10.11868/j.issn.1005-5053.2017.000204
2019, 39(1): 96-101
doi: 10.11868/j.issn.1005-5053.2018.000055
2019, 39(1): 102-107
doi: 10.11868/j.issn.1005-5053.2017.000035
2018, 38(2): 59-69
doi: 10.11868/j.issn.1005-5053.2018.001002
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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