航空材料学报

2018, 38(6): .

[Abstract](2150) [PDF 950KB](27)

Abstract:

Research Progress of Laser Shock Treatment in the Field of Material Forming

Fenghuai YANG, Guoxin LU, Qingtian YANG, Yongkang ZHANG

2018, 38(6): 1-10.

[Abstract](5133) [FullText HTML] (2928) [PDF 1046KB](85)

Abstract:
Laser shock treatment is a kind of advanced surface strengthening technology for metallic materials, and its remarkable strengthening effect has been verified and universally accepted in many different metallic materials. In order to prevent the influence of laser shock on the shape size of precision parts or make use of the technology to introduce plastic deformation of metallic materials, it is necessary to study the deformation criterion of materials under laser shock. In this paper, the deformation law of different materials treated by laser shock is analyzed, and the limitation of laser shock in deformation phenomenon is explained based on the deformation mechanism of stress gradient and impact bending, the necessity of basic research on material deformation caused by laser shock is proposed. The effect of many factors such as laser parameters and impact modes, constraint modes on the laser shock-induced deformation is summarized, and it is proved that the adjustment and optimization of multiple parameters play an important role in controlling laser shock-induced deformation degree. Moreover, the advantages of numerical simulation method in the study of laser shock-induced deformation are analyzed in this paper, and at the same time,the urgency of establishing a material constitutive model adapting to high strain rate deformation and perfecting the simulation of laser plasma formation process is put forward. The development of laser shock deformation law in advanced manufacturing industry is prospected through the introduction of the sizing technology of laser shock, and the research directions of the deformation calibration based on laser shock and the on-line monitoring of deformation degree are presented.

Heat and Light Synergy Response of FTO/CdTe/Bi₂Te₃ Nanostructure Heterojunction Thin Film

Bingwei LUO, Dabo LIU, Yuan DENG, Zhiwei ZHANG, Haitao ZHOU, Fei LUO, Ye TIAN, Dongsheng CHEN

2018, 38(6): 11-18.

[Abstract](2394) [FullText HTML] (1376) [PDF 834KB](33)

Abstract:
CdTe photoelectric material with one-dimensional nanostructure and Bi₂Te₃ thermoelectric material were successively grown on FTO substrate by magnetron sputtering method for forming FTO/CdTe/Bi₂Te₃ heterojunction thin film. Whereafter, a power device was prepared by processing Ag electrode. The property of the device with light and heat synergy response was characterized by the V-t curve, which was collected through the circuit and optical path design. With the time difference between light and heat response, the curve of voltage-time was collected under the different light source, electrode contact point and light illumination direction. Meanwhile, the phenomenon of light and heat synergy response was identified with the illumination intensity of halogen and xenon light changeable. The results show that the synergy of photoelectric material and thermoelectric material in a single cell of CdTe/Bi₂Te₃ heterojunction can realize the light and heat synergy response, and it is anticipated to harvest solar energy from a wider solar spectrum.

Thermodynamic Calculation and Analysis of Equilibrium Precipitated Phases in Mar-M247 Superalloy

Ning AN, Xiaofei YUAN, Yongji NIU, Jianjun TIAN, Zhenrui LI

2018, 38(6): 19-28.

[Abstract](2966) [FullText HTML] (1485) [PDF 1091KB](49)

Abstract:
Effects of alloying elements on the equilibrium precipitated phases, incipient and final melting temperature of Mar-M247 superalloy were studied through thermodynamic calculation. The results show that the main phases are γ' precipitates, MC, M₆C, M₂₃C₆ carbides, μ phases, MB₂ and M₃B₂ borides. Hf and Ta segregate more seriously mostly during solidification process. Around the composition range, Cr, Mo, Ti and Hf influence the initial melting temperature mostly. Precipitation temperature and precipitation amount of carbides increase linearly with the increase of the C content. Furthermore, Hf, Ti and Ta are contributed to the precipitation of MC carbides, Cr improves the precipitation of M₂₃C₆ and W and Mo are beneficial to the precipitation of M₆C. The precipitation of μ phase is mainly influenced by Mo and W, the precipitation temperature and mass fraction of μ phase increase as the content of Mo and W increase. The precipitation behavior of γ' phase is affected by Al, Ti and Ta contents, and their effects decrease in turn.

Effect of Heat Treatment Temperature on Microstructure and Mechanical Properties of Co-Cr-W Alloy

Yu CUI, Yuan SUN, Xingyu HOU, Hongyu ZHANG, Shuling XUN, Guichen HOU, Wenqiang LIU, Yizhou ZHOU

2018, 38(6): 29-35.

[Abstract](2643) [FullText HTML] (1342) [PDF 997KB](48)

Abstract:
Co-Cr-W alloy was prepared by powder metallurgy technology. The effect of heat treatment temperature on the microstructure and mechanical properties of the prepared alloy was investigated by SEM and EPMA, etc. The results show that the phases in Co-Cr-W alloy under the heat treatment condition of 1100 ℃ with holding time of 4 h and cooling without power is the same as before heat treatment. The matrix of alloy is composed of γ-Co with FCC structure, ε-Co with HCP structure, and the reinforced phases include M₆C and M₂₃C₆ carbides. The matrix of Co-Cr-W alloy under the heat treatment condition of 1150-1250 ℃ × 4 h is composed of single γ-Co in FCC structure and reinforced phases include M₆C carbides and M₂₃C₆ carbides. When the heat treatment temperature is increased from 1100 ℃ to 1200 ℃, the blocky M₆C carbides and granular M₂₃C₆ carbides grow up, meanwhile ε-Co phases are reduced and then disappeared, alloy density is improved, and tensile strength is increased. However, when the heat treatment temperature is above 1200 ℃, the performance of Co-Cr-W alloy has no obvious change, and the prepared alloy under the heat treatment condition of 1200 ℃ × 4 h achieves the optimal property with the average hardness of 63.5HRC and tensile strength of 408 MPa.

Process Parameters, Characteristics and Properties of Anodic Thermal Control Coating of Magnesium-Lithium Alloy

Yunyan LIU, Jiafeng LI, Ligong ZHANG, Xuecheng CHEN, Jingying BAI, Qingxin CUI

2018, 38(6): 36-42.

[Abstract](2669) [FullText HTML] (1464) [PDF 988KB](28)

Abstract:
Effects of current density, oxidation time and sealing on thermal control properties of anodic coatings of magnesium-lithium alloy were investigated. The microstructure, thermal control properties, adhesion properties, thickness, thermal cycling test and corrosion resistance were studied. The results indicate that high infrared emittance (ε_H) increases with the increase of current density and oxidation time, eventually stabilizes at around 0.85. Sealing has little effect on high infrared emittance (ε_H); variation of ε_H is in the range of less than 0.05. After 96 h neutral salt spray test, the coating shows good corrosion resistance.

Effect of Y-La Addition on Interfacial Reaction and Cyclic Oxidation Behavior of Nickel-based Single Crystal Superalloy

Genfeng SHANG, Jinfa LIAO, Hang WANG

2018, 38(6): 43-49.

[Abstract](2392) [FullText HTML] (1348) [PDF 816KB](26)

Abstract:
Y-La was added into the second generation of nickel base single crystal superalloy and two kinds of alloy castings with Y-La content of 5.26 × 10^–4%(mass fraction, ) Y + 6.05 × 10^–4% La and 47.64 × 10^–4% Y + 69.09 × 10^–4% La were obtained after directional solidification. The effect of Y-La content on the interface reaction between alloy melts and Al₂O₃ based ceramics during directional solidification was investigated. The effect of alloy content on oxidation resistance of alloy at 1100 ^oC under cyclic oxidation was studied. The microstructure at the interface between alloy and mould, as well as the surface cross-section and fracture morphologies of the specimens, was characterized by means of scanning electron microscope (SME) with an energy-dispersive spectroscopy attachment. The phases of the oxides were identified by X-ray diffraction. The results show that the increase of Y-La content promotes the interfacial reaction, which makes the reaction layer thicker and more complex. The main reaction products are oxides containing Y and La. The addition of Y-La obviously improves the oxidation resistance of the alloy and reduces the exfoliation of the oxide film on the surface of the alloy. However, excessive Y-La will deteriorate the oxidation resistance of the alloy, accelerate the oxidation weight gain rate of the alloy. And the oxide film of the alloy surface has obvious traces of exfoliation, more holes and serious internal oxidation.

Anisotropy of Microstructure and Mechanical Properties of Hastelloy X Alloy Produced by Selective Laser Melting

Yongzhi ZHANG, Huipeng HOU, Shuang PENG, Jie WANG, Yin WANG, Liming LEI

2018, 38(6): 50-56.

[Abstract](2501) [FullText HTML] (1454) [PDF 842KB](55)

Abstract:
Selective laser melting (SLM) was used to fabricate Hastelloy X alloy. The characteristics of grains and precipitates in Hastelloy X alloy processed by heat treatments (HT) and hot isostatic pressing (HIP) was analyzed. Furthermore, the tensile property of Hastelloy X alloys at ambient temperature and elevated temperature was investigated. Some grains exhibit columnar crystal morphology in vertically built samples, while the grains are equiaxial in horizontally built samples. The carbide phases with cubic structure are formed within grains and at grain boundaries simultaneously after a combination of HT and HIP. The horizontally built samples exhibits high tensile strength and low plasticity compared with the vertically built ones. Both of vertically built and horizontally built samples show predominantly ductile failure as characterized by dimpled microstructure. The tensile strength of Hastelloy X alloy at ambient temperature produced by SLM is 95% higher than that of hot forged alloy, while the tensile strength at 600℃ is about 85% of hot forged ones.

Preparation and Properties of Electro-induced Shape Memory Composites

Tianning REN, Guangming ZHU, Yangyang HAN

2018, 38(6): 57-63.

[Abstract](2552) [FullText HTML] (1365) [PDF 828KB](46)

Abstract:
Using BACE / PBEP polymer as matrix and superconducting carbon black (CB) as reinforcing material, the shape memory composites was prepared by compression molding. The effect of carbon black content on the shape memory properties and electro-induced efficiency of shape memory composites was studied. The results show that the shape memory composites can be completely recovered to its initial state under 180 V, when the shape fixation rate is 100%, CB content is 2.4%, and the conductive pathway is formed. With the increase of carbon black content, the deployable strength is also gradually increased, when the CB content is 2.6%, the maximum deployable strength reaches 0.05 MPa.

Phase Morphology and Chemorheology during Curing of Polyethersulfone/Bismaleimide Multi-phase System

Huimin DONG, Biao YU, Li YAN, Xuefeng AN, Huanghai QIAN, Yueteng LI, Zhengtao SU

2018, 38(6): 64-70.

[Abstract](2436) [FullText HTML] (1422) [PDF 931KB](36)

Abstract:
Curing characteristic of bismaleimide (BMI)/polyethersulfone (PES) multi-phase systems was studied by differential scanning calorimetry (DSC) using the non-isothermal method under different heating rates. The phase morphological evolution of BMI/PES-20 resin with the curing temperature and time was investigated by SEM. The chemorheology of BMI/PES was researched by rotational rheometer. Eventually, the relationship between phase separation and rheological properties was discussed. The results indicate that with the increase of the heating rate, the curing rate increases, and the curing characteristic temperatures of BMI/PES-25 systems shift toward higher temperature values but the curing enthalpy values are almost constant. With the increases of temperature, the viscosity keeps constant at low temperature in the curing temperature range of 110-150 ℃, and then increases rapidly. The temperature range, in which resin system maintains low viscosity, is widened with the increase of PES content. The viscosity of BMI/PES-25 displays a remarkable decrease in the curing temperature range of 180-200 ℃, as attributed to the phenomenon that the co-continuous structures convert to the phase inversion structures. The viscosity of BMI/PES-20 has no obvious change in the curing temperature range of 190-200 ℃, and increases rapidly above 200 ℃. The viscosities of BMI/PES-15, BMI/PES-10 and BMI/PES-5 resin systems increase rapidly above 180 ℃. SEM shows that these BMI/PES resins exhibit the ripening of phase structure during the temperature range of 180-200 ℃.

Influence of Imidization Method on Properties of Fluorinated Polyimide Films

Mingyan ZHANG, Sheng GAO, Zijian WU, Hongyu CUI, Yan GAO

2018, 38(6): 71-76.

[Abstract](2307) [FullText HTML] (1361) [PDF 672KB](35)

Abstract:
Thermal imidization restricts the application of fluorinated polyimide, but the low temperature imidization could cause a certain impact on its performance. PAA was synthesized with fluorinated monomer 4, 4'-(six fluoro isopropenyl) phthalic anhydride (6FDA) and 4 4'-, two amino -2, 2'- three fluorine biphenyl (TFMB), and then through gradient heating by 80 ℃/1 h, 110 ℃/2 h, 150 ℃/2 h, 200 ℃/1 h, 250 ℃/30 min, 300 ℃/30 min and adding acetic anhydride /pyridine mixture into PAA, two kinds of PI films were prepared and characterized. The test results show that PI films prepared by chemical imidization has better transparency, solubility and mechanical properties, while the PI films prepared by thermal imidization has smaller relative dielectric constant, and higher initial decomposition temperature and higher imidization rate.

Influence of Composite Absorbent Modification on Electromagnetic Properties

Zheng LIU, Shan HE, Daqing HUANG

2018, 38(6): 77-82.

[Abstract](2439) [FullText HTML] (1443) [PDF 721KB](34)

Abstract:
Coupling agent is one of the most common surface modifiers which is widely used in the field of absorbing material. Modification of absorbing material by coupling agent is the research hotspot. Herein, the absorbing material was prepared and modified by two kinds of absorbents (Ba(Zn_1-xCo_x)₂Fe₁₆O₂₇ and CIP) and AMEO coupling agent. The effect of absorbent modification on the macrostructure of absorbents was investigated by SEM. The electromagnetic properties of Ba(Zn_1-xCo_x)₂Fe₁₆O₂₇ and CIP were tested and discussed in detail. The difference between theoretical value and actual value of electromagnetic properties of absorbers was discussed by effective medium theory. The experimental results show that the absorbent modification can adjust the electromagnetic properties of absorbing material. The reflectivity of absorbing material after the modification is less than –10 dB in the range of 8 GHz to 18 GHz, and showes a minimum reflection of –14.5 dB. Furthermore, the absorbing material has a higher tensile strength (6.32 MPa). After the test of resistance to environment, no obvious changes are appeared from the absorbing material, reflectivity and adhesive force. The absorbing material has a good property of resistance to environment.

Experimental Study on Delamination of Composite Laminates with 0°/45° Interface under Mode I, Mode II and Mixed-mode I/II Loading

Yana WANG, Xinwen CHEN, Yu GONG

2018, 38(6): 83-88.

[Abstract](2703) [FullText HTML] (1430) [PDF 975KB](67)

Abstract:
High performance carbon-reinforced composite materials have become important aeronautical materials. During the service time, the delamination fracture of composite structures is a common failure mode. In this study, in order to investigate the delamination behaviours of T800/epoxy composite materials under different mixture ratios, DCB, ENF and MMB tests were conducted on composite laminates with pre-set 0°/45° interface respectively. From the test, the initial delamination fracture toughness and delamination growth behaviour were obtained. The test results show that the fracture toughness and delamination behaviour are significantly affected by the mixture ratio. With the increase of mixture ratio, the fracture toughness increases, and steady delamination growth behaviour is more difficult to maintain. Based on the data fitting method, a prediction function for fracture toughness of the 0°/45° interface at arbitrary mixture ratio is established, which has some engineering values.

Non-destructive Evaluation Method of Large-scale Casting Piece Based on Metallographic Structure Statistical Analysis

Wenzheng ZHAO, Xiwang QIE, Guoqing WU, Hai NAN, Zheng HUANG

2018, 38(6): 89-96.

[Abstract](2282) [FullText HTML] (1400) [PDF 864KB](29)

Abstract:
Aimed at the great metallographic structure differences between every part of the large-scale thin-wall complex integral precise titanium alloy casting, a non-destructive evaluation method based on metallographic structure statistical analysis is proposed. Under the non-destructive condition, the casting skin structure information is given by means of handheld microscope. The casting skin structure statistic model is established. And the result of integral casting structure is given. Through comparative analysis between non-destructive evaluation (Method A) and metallography detection of the dissect sample (Method B), the results show that the non-destructive evaluation evaluates the metallographic structure effectively. The mean value and half-width of the grain size distribution curves fit the characteristic of Gaussian distribution. And the grain size mean value in both two methods increase linearly along with the casting thickness, and the slope deviation is within the limits of 6%; the half-width relative deviation increases exponentially along with the casting thickness, approached 26%.

2018 Vol. 38, No. 6