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Microstructure and Mechanical Properties of ZrC-TaC Ceramic Prepared by Hot Pressing Sintering
Yan ZHANG, Yingkui GUO
, , doi: 10.11868/j.issn.1005-5053.2017.000196
[Abstract](71) [FullText HTML](54) [PDF 1662KB](4)
Zirconium carbide which is a kind of ultra high temperature ceramics, has broad application prospects in the aerospace, nuclear technology, electronics and other fields. In order to improve the sintering properties and mechanical properties of ZrC ceramics, using ZrO2 powder and TaO2 powder as raw materials, TaC and ZrC solid solution powder were prepared by carbon thermal reduction, and the hot pressing sintering process was used to prepare ZrC-TaC ceramics. The effect of the sintering temperature on the solid solution behavior, densification behavior, tissue structure and mechanical properties is studied. The results show that the TaC in ZrC solid solubility is enhanced when the temperature is increased from 2000 ℃ to 2050 ℃.When TaC content is increased from 5% to 15%, the density of the composite, vickers hardness, fracture toughness and elastic modulus is increased monotonously, and the bending strength is decreased.
Thermal Post-buckling Behavior of Ceramic-based FGM Circular Plates with linear variable thickness
Qing-lu LI, Peng-fei DUAN, Jing-hua ZHANG
, , doi: 10.11868/j.issn.1005-5053.2017.00035
[Abstract](130) [FullText HTML](76) [PDF 661KB](8)
The governing differential equations of Ceramic-based functionally graded material (FGM) circular plate with linear variable thickness along the radius in thermal environment were established. The thermal post-buckling behaviors of variable thickness FGM circular plate made of Ceramic and Metal in thermal environment were proposed by shooting method technique. The equilibrium paths of the FGM variable thickness circular plate subjected to uniform temperature rise and heat conduction are presented. The influence of ceramic gradient index and thickness variation coefficient on post buckling behavior is discussed. The numerical results show that the thermal critical load of non-uniform temperature rise is less than the one under uniform load. The change of radial thickness does not affect the thermal critical load value, but that will affect the post-buckling equilibrium path. The center deflection increases with the increase of variable thickness coefficient.
Precipitate Phases of Electron Beam Welded Joint in Superalloy Dissimilar Materials
Jin LIU, Zhiyi ZHAO
, , doi: 10.11868/j.issn.1005-5053.2018.000008
[Abstract](88) [FullText HTML](62) [PDF 1381KB](5)
The precipitate phases of electron beam welded joint in GH141/GH907 superalloy dissimilar materials were studied by scanning electron microscopy (SEM), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS). The welded joint contains GH141 heat affected zone, GH907 heat affected zone and weld area. The results indicate that there is no new precipitate phase in the heat affected zones of electron beam welding. Under the current heat treatment process, the precipitate phases of GH141 heat affected zone are square granular γ′ phases which are covered in matrix densely, thick massive MC type carbides with random distribution and the M6C type carbides which are precipitated mostly in the grain boundaries. Precipitate phases of GH907 heat affected zone are needle shaped ε phases covered in matrix densely and block G phases Nb3Ni2Si which are dispersed distribution. Precipitate phases of weld area are different from the two kinds of welding materials. One of them is a new needle shaped phase which has parallel or staggered distribution, and the other one is a tiny square or ellipsoid granular new precipitate phase which is proved to be orthogonal crystal system NbTi4 phase.
Rare-earth Element doped YSZ/YSZ Multilayer Thermal Barrier Coating with High Infrared Reflectivity
wei YANG, Yufeng WANG
, , doi: 10.11868/j.issn.1005-5053.2016.000233
[Abstract](60) [FullText HTML](55) [PDF 1075KB](3)
The operating temperature of advanced aeroturbine engine increases rapidly for higher working efficiency. Thermal barrier coatings (TBCs) with high temperature capability and thermal insulation effect are required. In this work, a novel multilayer TBCs consisting of rare-earth element doped YSZ and YSZ sublayers were designed and fabricated. The influence of microstructure to the phase structure, thermal conductivity and infrared reflectivity of the coatings were investigated. The results show that a preferred orientation of (200) is yielded in the coating. With the increase of layers, the thermal conductivity of the coating decreases and the infrared reflectivity increases respectively. The multilayer coating with 200 sublayers exhibits a thermal conductivity of 1.1-1.16 W/m·K, 11% lower than that of the conventional single layer coating. The infrared reflectivity of the coating reaches as high as 48%-55%.
Research Progress in Preparation and Crystallization Technologies of Amorphous ITO Film
Jiaming LI, Liangbao JIANG, Mu CHEN, Xiaoyu LI, Youxiu WEI, Xiaofeng ZHANG, Yibo MA, Yue YAN
, , doi: 10.11868/j.issn.1005-5053.2017.000035
[Abstract](117) [FullText HTML](73) [PDF 851KB](15)
Transparent conductive oxide films have been widely used in liquid crystal displays, solar cells, electrochromic windows, gas sensors, curtain wall glass, heat-transfer glass for aircraft and high-speed trains (de-icing and defogging). The study of its preparation and treatment methods is also crucial and important. In order to prepare a highly transmissive and highly conductive ITO film, it is generally obtained by two methods: a crystalline high-quality thin film is deposited by a high-temperature preparation method directly, and an amorphous film is deposited at room temperature and then heat-treated. However, for substrates that are not resistant to high temperatures, they cannot be exposed to high temperatures for long periods of time. Therefore, it is significant to study the rapid heat treatment crystallization method, aiming at not only ensuring the application requirements of the ITO film, but also reducing the adverse effect of the crystallization method on the substrate. According to different application backgrounds and application requirements, selecting the appropriate preparation method and crystallization method are the key issues to obtaining highly transmissive and highly conductive films. This paper summarizes the current research progress of crystallization methods of ITO transparent conductive oxide films both at home and abroad. By comparing the mechanism, advantages and disadvantages of different thin film crystallization methods, it is found that the infrared annealing, laser annealing, and flash lamp annealing can achieve rapid crystallization of the thin film, and the temperature of substrate is lower than the temperature of film during the process. These methods are expected to replace the conventional furnace annealing crystallization method used in current commercial production for improving production efficiency, saving production costs, obtaining high-quality and high-performance transparent conductive oxide film. These methods are expected to be more widely used.
Formation Mechanism and Restraining Measures of Burning-on of DZ22B Directionally Solidified Blade
Fei LI, Xiaoyan CHEN, Yanjie ZHAO, Fei WANG, Baode SUN, Dongke SUN, Zhenfeng LI
, , doi: 10.11868/j.issn.1005-5053.2018.000019
[Abstract](98) [FullText HTML](79) [PDF 1161KB](7)
The microstructure and chemical composition of the burning-on layer of the directionally solidified blade of the DZ22B supperalloy were studied by means of SEM and EDS. The results show that the metal ceramic like sand defects are formed by a part of ceramic particles covered during the infilfration of metal to shell surface pores. The main component of the burning-on layer composes fused corundum, with some interfacial reaction products containing Cr2O3 and HfO2. According to the results of SEM analysis of blade cross section, the mechanism of the burning-on of the DZ22B directionally solidified blade is mainly caused by thermo mechanical permeation. A certain amount of burning-on inhibitor is added to the shell surface slurry, which significantly improves the penetration resistance of the fused corundum shell surface. The casting verifies that the surface of the DZ22B directionally solidified blade is smooth without burning-on, and the metallic luster on the blade surface is obviously observed.
Effect of Impact Damage and Open Hole on Typical Mechanical Properties of CYCOM 7701/7781 Fiberglass Epoxy Composite Lamina
Qingyu GUAN
, , doi: 10.11868/j.issn.1005-5053.2018.000002
[Abstract](47) [FullText HTML](37) [PDF 556KB](3)
CYCOM 7701/7781 fiberglass epoxy fabric prepreg was used to fabricate the composite lamina specimens through medium temperature curing process. The specimens were categorized into three groups. The tensile strength of unnotched and open-hole specimens, the compressive strength of unnotched and open-hole specimens, and the compressive strength after impact were respectively tested under three conditions of cold temperature dry (CTD), room temperature dry (RTD), and elevated temperature wet (ETW). The effects of impact and open hole on typical mechanical properties of CYCOM 7701/7781 composite lamina were studied. The results show that the open-hole makes the average tensile strength decrease by about 50% under the CTD, RTD and ETW conditions, and decrease the coefficients of variation of the tensile strength. Impact damage and open-hole have similar disadvantageous effects on the average compressive strength under CTD and RTD environment condition, which decrease the average compressive strength by about 45%-55%, while the impact damage and open-hole have different effects on the compressive strength under ETW condition. The compressive strength is decreased about 50% by the open-hole and about 30% by the impact damage under ETW condition. It is indicating that the effect of open-hole condition is more severe than that of impact damage condition under ETW condition.
Progressive Damage Based Failure Analysis of Open-hole Composite Laminates under Tension
Rupeng LI, Lei CHEN, Xueshu LIU, Xiangqian ZENG, Hang GAO
, , doi: 10.11868/j.issn.1005-5053.2017.000133
[Abstract](132) [FullText HTML](56) [PDF 3967KB](3)
To investigate the failure behavior of open-hole carbon fiber reinforced plastics (CFRP) under the circumstance of tensile loading, three-dimensional Hashin failure criteria was adopted to predict damage initiation, and a stiffness degradation method based on progressive damage theory was proposed to assess the damage evolution. The subroutine UMAT was developed to numerically analyze the loading capacity and failure behavior of open-hole CFRP laminates under tension. The numerical prediction of ultimate loading capacity and failure procedure are compared with the experimental data, and the results are indentical. Therefore, the effectiveness and accuracy of the proposed method are validated.
Effect of Surface Treatment on Durability of GFRP Reinforced Aluminum Structure under Hygrothermal Environment
Zhonhui YU, Peizhong ZHAO, Fangyou HU
, , doi: 10.11868/j.issn.1005-5053.2016.000171
[Abstract](60) [FullText HTML](42) [PDF 1519KB](4)
The aluminum alloy surface was treated through three different processes. The bonding strength of GFRP-aluminum under hygrothermal environment with different surface treatments was tested and was arranged with the order of anodizing > silane coupling agent > sand blasting. The effects of hygrothermal environment and surface treatment on repair effects were also studied by tensile tests of GFRP and GFRP reinforced aluminum. The results show that the tensile strength, elastic modulus and break elongation of GFRP decrease after wet and heat treatments. After different surface treatments, the initial loads of repaired specimens increase with the order of anodizing > silane coupling agent > sand blasting. The bearing capacities of the specimens repaired by different surface treatments are reduced to different degrees under hygrothermal environment. For sand blasting specimen, the declining of bonding strength of the resin-aluminum is the main cause of the declining of bearing capacity, and damage mainly occurs in the interface. For the silane coupling agent and anodic specimen, damage occurs mainly in the resin-GFRP interface, the mechanical property of resin-aluminum interface is better than that of resin-GFRP.
Progress on Self-Healing and Structure-Wave Absorbing Integration of Silicon Carbide Ceramic Matrix Composites
Xiaokang MA, Xiaowei YIN, Xiaomeng FAN, Laifei CHENG, Litong ZHANG
, , doi: 10.11868/j.issn.1005-5053.2017.00000
[Abstract](61) [FullText HTML](42) [PDF 800KB](3)
In order to meet the need of high thrust ratio aero engine working in long term thermal oxidation environment and the stealth requirement of key thermal structural components of aero engine, silicon carbide ceramic matrix composites are developing towards crack self-healing and structure-wave absorbing integration. In this paper, the design principles of silicon carbide ceramic matrix composites in strengthening and toughening, crack self-healing and electromagnetic wave absorption are introduced. The research progress in these three aspects is reviewed. The future development trend of structural and functional CMC-SiC is the combination of high strength and toughness, self-healing antioxidation and electromagnetic wave absorption.
Microstructures and Properties of a Low-Density Steel with High Strength of 1350 MPa
Zhihua JIANG, Jianjun JIN, Xiaozhen WANG, Chunwen HU, Zhiming NI
, , doi: 10.11868/j.issn.1005-5053.2018.000032
[Abstract](19) [FullText HTML](9) [PDF 1485KB](0)
A low-density steel Fe-20Mn-10Al-1.0C with high strength of 1350 MPa was developed. The mechanical properties and microstructure evolutions of Fe-20Mn-10Al-1.0C steel under various heat treatment conditions were investigated by means of optical microscopy, X-ray diffraction and high resolution electron microscopy. The results show that the alloy goes through spinodal decomposition leading to the L′12 ordered phase-κ′ carbide (Fe, Mn)3AlCxformation. After solution-treatment at 950 ℃, diffused precipitates of (Fe, Mn)3AlCxwith the size of 2-5 nm forme inside the austenite substrate. After the subsequent ageing process, the size of κ′ carbides increases, and the particles tend to be aligned and agglomerated along the<100>directions as the aging temperature increases. Periodic modulated structures are finally formed resembling regular "checkered lattice". Ordering effect strengthening by the nano-sized κ′ carbides and elastic misfit strengthening by spinodal decomposition cause a high tensile strength up to 1350 MPa with a good elongation, and the density is lower than 6.80 g/cm3.
Influence of Electrical Conductivity on Ablation Damage Degree Subjected to Lightning Strike
Yao XIAO, Shulin LI, Yuqian WANG, Fei CHANG, Junjie YIN
[Abstract](47) [FullText HTML](20) [PDF 877KB](0)
According to the energy conversion relationship during the lightning strike, a lightning damage analysis model based on coupled electrical-thermal simulation for composites was established. he variation of electrical conductivity with pyrolysis. By means of the model, the lightning ablation damage of the composite material multiple change conductivity was compared. The results show that under the same lightning current parameters, the electrical conductivity changes of composite materials in different directions have different effects on the ablation damage caused by lightning strikes. he electrical conductivity along the fiber direction, the apparent damage area decreases the electrical conductivity perpendicular to the fiber direction increases, the apparent damage area increases he electrical conductivity along the ,the damage depth increases. ny of the three directions increases , the total damage volume of the composite decreases. When the conductivity of each direction increases by 13 orders of magnitude, the greatest changes in damage volume observed along the fiber direction, wih decrease 47.83%, 75.08%, and 97.82% respectively, followed by changes along the thickness direction, wih decrease 36.25%, 53.44%, and 65.54%, the least perpendicular to the fiber direction, which reduced by 8.72. %, 12.58% and 24.76%. ncreasthe conductivity of the composite material play a significant role in lightning strike protection. A comprehensive assessment of the lightning protection effect requires a combination of two-dimensional damage and three-dimensional damage.
Prediction for Contact Fatigue Life of Plasma Sprayed Coating Based on Weibull Distribution
Xiaoyu FEI, Guolu LI, Haidou WANG
, , doi: 10.11868/j.issn.1005-5053.2017.000188
[Abstract](16) [FullText HTML](13) [PDF 689KB](1)
Weibull distribution is one of the most commonly statistical methods used to deal with and analyse fatigue life, but in the study of contact fatigue life of coating, most scholars established the Weibull distribution model without multivariate statistical analysis, which affected the accuracy of the model to a certain extent. In this work, NiCrBSi alloy coating was deposited on steel (AISI 1045) substrates using supersonic plasma spraying technique. Rolling contact fatigue (RCF) life of the coating was investigated using a ball-on-disc tester under different loads. The contact fatigue life of the coating was verified by Fan-Montfort test. The results show that the RCF life of different loads accords with Weibull distribution. The map of Weibull distribution failure probability was plotted. The coating failure probability at any number of cycles under the same working conditions can be observed intuitively through the map. The regression equation of RCF life and loading was established, it shows that the logarithm of characteristic life is linear associated with the loading and the regression model can accurately characterize the contact fatigue life of coatings in a certain range.
Influence of Composite Absorbent Modification on Electromagnetic Properties
Zheng LIU, Shan HE, Daqing HUANG
, , doi: 10.11868/j.issn.1005-5053.2014.3.002
[Abstract](31) [FullText HTML](14) [PDF 663KB](0)
Coupling agent is one of the most common surface modifiers which are widely used in the field of absorbing material. Modification of absorbing material by coupling agent is the research hotspot. Herein, the absorbing material was prepared and modified by two kinds of absorbents (Ba(Zn1-xCox)2Fe16O27 and CIP) and AMEO coupling agent. The effect of absorbent modification on the macrostructure of absorbents was investigated by SEM. The electromagnetic properties of Ba(Zn1-xCox)2Fe16O27 and CIP were tested and discussed in detail. The difference between theoretical value and actual value of electromagnetic properties of absorbers was discussed by effective medium theory. The experimental results shown that the absorbent modification can adjust the electromagnetic properties of absorbing material. The reflectivity of absorbing material after modification was less than –10 dB in the range of 8 GHz to 18 GHz and showed a minimum reflection of –14.5 dB.
Research Progress in Cemented Carbide with Co-Ni-Al Composite Binder Phase
Jian-zhan LONG, Yong DU, Bi-zhi LU, Wei-bing ZHANG, Tao XU, Zhong-jian ZHANG, Mao-zhong YI
[Abstract](105) [FullText HTML](58) [PDF 2621KB](8)
The application background of Co-Ni-Al composite binder phase in cemented carbide was introduced. The latest research results of Co-based superalloy and the properties of cemented carbide with binder strengthened by ordered phase were briefly described. The application of integrated computational material engineering in the research and development of Co-Ni-Al composite binder was introduced. The progress in the preparation, microstructure characterization and performance of WC-Co-Ni-Al cemented carbides were summarized. The results show the composition of Co-Ni-Al composite binder has obvious influence on the solid-liquid interface energy and the liquid-phase nucleation driving force of the alloy. Accordingly, the grain size of the binder phase and the grain morphology of WC are affected. Ultimately these factors affect the performance of the alloy. It is pointed out that the performance of cemented carbide strengthened by ordered γ′ phase precipitation can be improved significantly. It is expected to obtain high-performance cemented carbide materials with excellent high-temperature resistance, corrosion resistance, and oxidation resistance. It is proposed that the interfacial microstructure, the relationship between C content and precipitation phase and the anti-wear mechanism of cemented carbide with Co-Ni-Al composite binder phase should be emphasized in future.
Progress in Research of Acrylonitrile-butadiene Rubber(NBR) Nanocomposites Filled with Graphene
Hui-min DONG, Wei-qi MU, Hai-yan SHI, Huang-hai QIAN, Ming Lu, Jia LIU
, , doi: 10.11868/
[Abstract](34) [FullText HTML](17) [PDF 717KB](1)
This article summarizes the preparation and functionalization of graphene, and introduces the fabrication methods of graphene/NBR nanocomposites including emulsion blending, solution blending, and mechanical blending. The mechanical properties, cure characteristics, fatigue properties, electrical conductivity, thermal behavior, tribological properties along with gas barrier properties were reviewed. With the further study of the molecular interaction between graphene and NBR, the structure and properties graphene/NBR will be gradually perceived. Finally, it is pointed out that the development of graphene/NBR nanocomposites in the field of medium corrosion resistance, radiation resistance, damping, flame retardancy will have more room to be expanded.

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2018, 38(4): 1-2.  
[Abstract](36) [FullText HTML](34) [PDF 268KB](5)
A Review on Mg-RE Alloys with High Product of Strength and Elongation
Yangxin LI, Xiaoqin ZENG
2018, 38(4): 1-9.   doi: 10.11868/j.issn.1005-5053.2018.001012
[Abstract](109) [FullText HTML](41) [PDF 781KB](4)
The combination of magnesium and rare-earth (RE) elements can produce the lightest constructional metals, i.e. Mg-RE alloys. These Mg-RE based alloys have been used in the fields of aerospace, electronics, communications, and automobiles, etc. However, most of the Mg alloys have been suffered from the " strength-ductility trade-off” phenomenon, which limits their applications. With the present of long period stacking ordered (LPSO) phases, the Mg-RE-X alloys usually exhibit high strength, high ductility and high creep resistance, and have drawn increasing interest due to their promising mechanical properties in the past two decades. This paper reviews the development of Mg-RE based alloys, proposes a concept of high " product of strength and elongation” Mg alloys, and three main issues to be solved in future, which are (1) formation and deformation mechanisms of different structural units within a single-crystal Mg grain; (2) strengthening and toughening mechanisms in polycrystal Mg alloys; (3) manipulation of different structural units to produce Mg alloys with high product of strength and elongation.
Research Progress of As-cast Magnesium Alloys with High Plasticity
Bin JIANG, Wenjun LIU, Hanwu DONG, Renju CHENG, Na ZHANG, Fusheng PAN
2018, 38(4): 10-25.   doi: 10.11868/j.issn.1005-5053.2018.001011
[Abstract](76) [FullText HTML](27) [PDF 635KB](2)
It is necessary for cast alloys possessing sufficient plasticity to be subjected to deforming progresses for the improvement of mechanical properties. Developing as-cast magnesium alloys with appreciated plasticity is therefore important to the variety of wrought magnesium alloys and the enlargement of their applications. In this paper, the research progresses of Mg-Al, Mg-Li, Mg-Zn and Mg-RE (rare earth) series magnesium alloys are enclosed, as well as the effects of casting processes. The plasticity enhancement of as-cast magnesium alloys was mainly attributed to the combination of the grain refinement and the second phases introduced by alloying elements, and microalloying with several alloying elements was more favorited. Heat treatment, rapid cooling casting and external electromagnetic field were also beneficial to mechanical properties and worth to be promoted in industrial engineering.
Current Study and Novel Ideas on Magnesium Matrix Composites
Yang HE, Qiuhong YUAN, Lan LUO, Yuhai JING, Yong LIU
2018, 38(4): 26-36.   doi: 10.11868/j.issn.1005-5053.2018.001013
[Abstract](228) [FullText HTML](59) [PDF 648KB](6)
Magnesium alloy is the lightest metal structural material, but its low strength, low plasticity and poor corrosion resistance severely limit its wide application as a light metal material in the engineering field. Magnesium matrix composites are considered to be one of the most advantageous ways to improve the mechanical properties of magnesium alloys and realize their industrial applications because of their high specific strength, specific stiffness, specific modulus and light weight. The article focuses on the current study of magnesium matrix composites enhanced by carbon nanotubes, graphene and SiC. The bottleneck of magnesium matrix composites is analyzed from the aspects of reinforcement dispersion, interface bonding and structural stability. The new ideas for the design of magnesium matrix composites are introduced from the aspects of surface modification of reinforcements, design of matrix alloy, and preparation process of the composite material. Also the development trend and research direction of future magnesium matrix composites are proposed.
Research Progress of Metal-Intermetallic Laminated Composites
Fantao KONG, Wei SUN, Fei YANG, Xiaopeng WANG, Yuyong CHEN
2018, 38(4): 37-46.   doi: 10.11868/j.issn.1005-5053.2017.000204
[Abstract](110) [FullText HTML](73) [PDF 2452KB](10)
Metal-intermetallic laminated composites not only retain the high temperature strength of intermetallics, but also possess the high toughness and ductility of metal at room temperature which are gradually becoming the research priorities of domestic and overseas researchers. In this article, authors introduced Ti-Al, Ni-Al, Fe-Al, Nb-Al and other common metal-intermetallic laminated composites and emphasized on the advantages and disadvantages of synthesis methods, such as hot-pressing, explosive welding, spark plasma sintering and so on. The toughening mechanisms inside and outside of metal-intermetallic laminated composites were summarized. Finally, the deficiencies about the research of metal-intermetallic laminated composites at present were analyzed. The research must focus on the Ti-Al laminated composite. Improving the ductility and toughness at room temperature, researching the toughening mechanism and optimizing the fabrication process are the key issues to the engineering application of metal-intermetallic laminated composites.
Research Progress on Deployable Structures of Shape Memory Polymer Composites
Tianning REN, Guangming ZHU, Jing NIE
2018, 38(4): 47-55.   doi: 10.11868/j.issn.1005-5053.2017.000159
[Abstract](107) [FullText HTML](83) [PDF 912KB](9)
As a new kind of smart material, shape memory polymers (SMPs) show great promise in aerospace. Intelligent material structure with low cost, smooth process, low vibration, high strength and excellent electrical conductivity, and its composite with a certain reinforced phase can be designed according to the mechanism, composition and structure of the polymeric material. In this paper, three kinds of matrix for shape memory polymer composites and the method of preparing shape memory structures for each matrix are introduced. From macro structures, the three kinds of SMPs are discussed in separate deployable structures. The shape-memory mechanism, recovery rate, fixed rate, and response speed are presented in detail. Also, some applications of shape memory polymer composites in space deployable structures are introduced.
Review Thermomechanical Processing and Microstructure of High Strength-toughness Titanium Alloy
Huan WANG, Yongqing ZHAO, Shewei XIN, Wei ZHOU, Qian LI, Siyuan ZHANG
2018, 38(4): 56-63.   doi: 10.11868/j.issn.1005-5053.2017.000193
[Abstract](70) [FullText HTML](54) [PDF 981KB](4)
High strength-toughness titanium alloy has gradually attracted considerable attention as important engineering material in aerospace industry. Forging is a main thermomechanical processing method in high strength titanium alloy, With the major purposes of refining grain and optimizing mechanical properties through microstructure control during the different stages of thermomechanical process. The grain refinement occurs mainly in the process of ingot breakdown and substituting forging, which affects the static and dynamic recrystallization of the alloy by controlling the forging temperature and deformation. The microstructure control is mainly occurred in the finished forging stage by controlling the forging temperature and phase transformation of the alloy. This article describes the research development of the thermomechanical process for high strength-toughness titanium alloys, summaries the effect on the microstructure of thermalmechaical process from the two aspects of refining the grain and controlling the structure from.
Effect of Mo content on Microstructure and Mechanical Properties of IN718 Alloy
Dawei HAN, Wenru SUN, Lianxu YU, Fang LIU, Bin ZHANG, Zhuangqi HU
2018, 38(4): 64-74.   doi: 10.11868/j.issn.1005-5053.2018.000025
[Abstract](125) [FullText HTML](90) [PDF 1652KB](19)
The effect of Mo content on microstructure and mechanical properties of IN718 alloy after standard heat treatment was investigated by means of optical microscopy(OM), scanning electron microscopy(SEM), transmission electron microscopy(TEM) and energy dispersive spectrometer(EDS). The results show that Mo significantly affects the intergranular precipitation. The amount of δ phase is decreased by the increase of Mo addition up to 4.00%. However, δ phase is inhibited thoroughly but Laves phase begins to precipitate at grain boundaries when Mo addition is higher than 5.50%, and the precipitation of Laves phase is increased by the increase of Mo content. Both the disk-shaped γ″ phase and spherical γ′ phase are precipitated in γ matrix grain in all of the alloys with the Mo additions ranging from 2.8% up to 7.5%, and there are no other second precipitates. Mo has no obvious effect on the number of the precipitation of γ″ phase and γ′ phase, but their sizes are decreased with the increase of Mo addition. Mo slightly reduces the tensile strength of IN718 alloy at room temperature and yield strength at 680 ℃. At room temperature, Mo addition lower than 5.5% has no evident effect on the tensile ductility, while the ductility is remarkably decreased when Mo addition is 7.50%. At 680 ℃, the ductility is enhanced gradually as Mo addition increases. Mo obviously improves the stress rupture life of IN718 alloy at 680 ℃ and 725 MPa. The life of the alloy with 7.50% Mo is about 1.5 times as long as that of the alloy with 2.8% Mo. Mo has no obvious effect on the tress rupture ductility.
Effect of Pressure on Microstructure and Mechanical Properties of Squeeze Casting Mg-6Zn-1Al-0.5Mn-0.5Ca Alloy
Rong WANG, Qichi LE, Engang WANG, Jianzhong CUI, Zheng REN, Xiangyu CHENG, Xiao ZHANG, Xiurong ZHU, Min CHEN
2018, 38(4): 75-81.   doi: 10.11868/j.issn.1005-5053.2017.000156
[Abstract](95) [FullText HTML](49) [PDF 2237KB](6)
The effect of pressure of squeeze casting on the microstructure and mechanical properties of Mg-6Zn-1Al-0.5Mn-0.5Ca alloy has been systematically studied using XRD. SEX. TEM and tensile test. The results show that the microstructure of the as-cast alloy consists of α-Mg matrix with τ(Mg32(Al, Zn)49) and some Al8Mn5 second phase particles. The imposed pressure dose not change the composition of alloy phase precipitation. With the increase of squeeze casting pressure, the second phase particles of the as-cast ZAMX6100 alloy becomes more and fine, and more uniformly distributed. Simultaneously, ZAMX6100 alloy solidified under pressure improves the uniform distribution of micro-elements Mn, Ca, which decreases the extent of interdendritic segregation. When pressure is increased from 0 MPa to 100 MPa, the tensile strength, yield strength, elongation and hardness of ZAMX6100 alloy are all improved by 27%, 14%, 31% and 9% respectively. The fine ZAMX6100 alloy microstructure is mainly caused by the atom spread activation energy decreasement under pressure during the solidification, which decreases the crystal growth velocity, and at the same time the high pressure squeeze casting causes an entire contact of magnesium alloy with the mold inside, which causes the increase of cooling rate and refinement of microstructure.
Wear and Corrosion Properties of Cold Sprayed 420 Stainless Steel/WC-17Co Coating on Magnesium Alloy
Jie CHEN, Hui SONG, Yu DAI, Bing MA, Ziyun ZHENG, Li JIA
2018, 38(4): 82-86.   doi: 10.11868/j.issn.1005-5053.2017.000161
[Abstract](72) [FullText HTML](47) [PDF 1636KB](6)
420/WC-17Co coating was deposited on AZ80 magnesium alloy substrate by cold spraying technology. SEM was used to characterize the original powder morphology and coating microstructure. The microhardness and bonding strength of as-sprayed coating were tested by microhardness tester and universal material testing machine. Moreover, friction and wear property of the coating was also investigated by a ball-on-disk tribometer. Corrosion behaviours of coatings and magnesium alloy were characterized by electrochemical measurements. The results show that high quality 420/WC-17Co coating can be deposited on AZ80 magnesium alloy by cold spraying technology. The microhardness of cold sprayed 420/WC-17Co coating is (615 ± 62) HV, bonding strength is (57 ± 11) MPa and wear rate is only 3.3 × 10–6 mm3·N·m. The wear resistance of cold sprayed 420/WC-17Co coating is improved by two orders of magnitude, and the corrosion current density is reduced by one order of magnitude than magnesium alloy substrate. In conclusion, the present research demonstrates that cold sprayed 420/WC-17Co coating can significantly improve the surface performance of magnesium alloy substrate without evident heating output.
Effect of SPS Sintering Temperature on Properties of ZrB2-SiC Ceramic
Qi LI, Fengwei GUO, Lamei CAO, Xiaosu YI
2018, 38(4): 87-92.   doi: 10.11868/j.issn.1005-5053.2017.000082
[Abstract](66) [FullText HTML](60) [PDF 807KB](9)
Two ZrB2-20% (volume fraction) SiC(ZS) ceramics were sintered successfully by spark plasma sintering (SPS) process at 1700 ℃ and 1900 ℃ respectively. The SEM, EDS, hardness, fracture toughness, bending strength, mass gain and cross section of oxidized ceramics were analyzed to investigate the effect of sintering temperature on microstructure, mechanical properties and oxidation resistance of ZS ceramic. The results show that the grain size and relative density of ZS ceramic are increased with the increase of sintering temperature. When the sintering temperature is raised from 1700 ℃ to 1900 ℃, the density increases from 98% to 99.8% and the hardness increases from 12.6 GPa to 14.7 GPa. With the increase of sintering temperature form 1700 ℃to 1900 ℃, the bending strength at 1600 ℃ increases from 101 MPa to 286 MPa, and the bending strength at 1800 ℃ increases from 138 MPa to 302 MPa. The oxidation behaviours of the two ceramics at 1500 ℃ in air are also investigated. The oxidation depth of ZS ceramic sintered at 1900 ℃ is smaller, and the infiltration of O into the substrate is less, which indicates that the oxidation resistance of ZS ceramic sintered at 1900 ℃ is improved.
Effect of Ultrasonic Vibration on Microstructure and Mechanical Properties of Nano-SiCp/Al-5Cu Composites
Jianyu LI, Shulin LYU, Shusen WU, Kang LU, Qi GAO
2018, 38(4): 93-100.   doi: 10.11868/j.issn.1005-5053.2017.000213
[Abstract](103) [FullText HTML](61) [PDF 2232KB](5)
The ultrasonic vibration (UV) treatment has been successfully applied to improve the particles distribution of nano-SiCp reinforced Al-5Cu composites fabricated by combined processes of dry high energy ball milling and squeeze casting. Large particles aggregates are eliminated by effects of the cavitation and the acoustic streaming of UV for 1 min. All the particles aggregates are eliminated and the particles are uniformly distributed in the melt after treated by UV for 5 min. The ultimate tensile strength, yield strength and elongation of the 1%(mass fraction) nano-sized SiCp/Al-5Cu composites treated by UV for 5 min are 270 MPa, 173 MPa and 13.3%, which are increased by 7.6%, 6.8% and 29% compared with Al-5Cu matrix alloy, respectively, and are increased by 27.4%, 9.5% and 303% compared with the untreated composites, respectively. The improvements of mechanical properties after UV are attributed to the uniform distribution of reinforcement and grain refinement of aluminum alloy matrix.
Effect of Rare Earth Y on Microstructure and Properties of Sn-58Bi Solder Alloy
Liukui GONG, Jinfa LIAO, Jihui YUAN, Guihe LI, Huiming CHEN
2018, 38(4): 101-108.   doi: 10.11868/j.issn.1005-5053.2018.000007
[Abstract](220) [FullText HTML](83) [PDF 3220KB](21)
Sn-58Bi-xY alloys with different Y contents (x = 0.0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% (mass fraction, the same below )) were fabricated in a vacuum furnace in nitrogen atmosphere. Microstructure, phase composition, melting characteristic, wettability and hardness of the alloys were investigated, and the influence of the rare earth Y on the formation of intermetallic compound among Sn-58Bi/Cu were analyzed, and the shear strength were test. The results show that the Sn-Bi microstructure is refined, and the microstructure of Sn-58Bi-xY is rich in Sn phase, Bi phase and eutectic microstructure of layered structure. The rare earth Y is distributed in rich Bi phase evenly. The melting points and melting ranges are less affected with the Y addition. The wettability of Sn-58Bi alloys reduces when the Y contents increase, but the hardness of Sn-58Bi alloys increases and reaches the maximum value 24.18HV when the content of Y is 0.4%. Rare earth Y can improve the shear strength of Sn-58Bi-xY/Cu solder joints, and the shear strength of the joints reach the maximum value 53.55 MPa when the content of Y is 0.2%. Y can promote the reaction of Sn-58Bi solder with Cu during welding and forming Cu6Sn5 intermetallic compound.
Direct Lightning Test Research on Composite Laminate with Copper Wire Mesh
Yao XIAO, Shulin LI, Junjie YIN, Xueling YAO, Xianhang ZHANG
2018, 38(4): 109-114.   doi: 10.11868/j.issn.1005-5053.2017.000117
[Abstract](48) [FullText HTML](34) [PDF 765KB](2)
In order to study the lightning protection effect of copper wire mesh on composite materials, two different lightning current waveforms were used to simulate the lightning current impact test on composite specimens with and without copper wire mesh in different sizes. Through visual damage observation, optical microscope amplification and ultrasonic damage scanning, the lightning damage degree and characteristics of composite materials were compared and analyzed. The experimental results show that when the lightning current waveform is 1 and peak currents are 50 kA and 80 kA, the lightning strike damage area and depth of the Type1 specimen without copper wire mesh are 1785 mm2, 0.63 mm and 3041 mm2, 0.96 mm respectively, while the test specimens with copper wire mesh in the same type are basically scatheless. When the lightning current waveform is 2 and the peak current is 40 KA, the lightning strike damage area and depth of the Type2 specimen without copper wire mesh are 2156.75 mm2, 0.36 mm, while the damage area of the test specimen with copper wire mesh in the same type is less than 100 mm2, and the inner layer has not been damaged. There exists a threshold value for the maximum lightning current strength of the 0.25 mm copper wire mesh, which can be expressed by the action integral. The lightning protection effect is independent of the specimen size, and is only related to the action integral, the corresponding threshold value of which is about 85218 A2·s.
Defect Control and Curing Process Simulation for T700/603 Composites
Guiyang LI, Guanghui ZHAO, Zhichang HAN, Hongjun GUO, Yanxia LI, Xiaonan ZHANG
2018, 38(4): 115-122.   doi: 10.11868/j.issn.1005-5053.2017.000002
[Abstract](83) [FullText HTML](76) [PDF 1064KB](6)
The autoclave curing process of advanced grid-stiffened MT300/603 composite has been simulated based on heat-conducting/curing-reaction and resin-flowing/fiber-compaction. The fiber volume fractions and internal defects were evaluated and investigated in term of the curing temperature, brazing time, pressure applying point and molding pressure, which were used to set up the defect control and process improvement. Furthermore, the ϕ1 m grid stiffened cylinder was prepared to verify the availability for this process optimization method. The results show that increasing pressure and enhancing pre-bulking can significantly improve the internal quality and load-carrying ability of ϕ1 m specimen.
Experimental Investigation of High-temperature Crack Propagation Behaviors for Ti-6Al-4V/ELI at 250
Zhiyang LYU, Junjiang XIONG, Yanguang ZHAO, Shaojun MA
2018, 38(4): 123-129.   doi: 10.11868/j.issn.1005-5053.2016.000155
[Abstract](63) [FullText HTML](39) [PDF 1127KB](3)
Fatigue crack propagation behaviors at high temperature are important preconditions for damage tolerance design in aircraft and engine structures.Therefore, fatigue tests were carried out on titanium alloy Ti-6Al-4V/ELI subjected to constant amplitude loading at two temperatures of 25 ℃ and 250 ℃ and three stress radios of 0.06, 0.5, -1 to determine fatigue crack propagation behaviors. Fatigue crack propagation da/dNK curves and da/dNK-R surfaces were obtained from experimental data by secant method. Those behaviors at different temperatures were compared and analyzed, and the interaction mechanism between high-temperature and fatigue load was deduced from fractographical study by SEM analysis.The results show that the larger the stress ratio R, the faster the rate of crack propagation of Ti-6Al-4V/ELI under the same temperature and stress intensity factors rangeΔK. Oxidation products and large numbers of secondary cracks are found on the fatigue fracture surfaces at high temperature and the destruction mode of crack propagation is gradually changed form cleavage to quasi-cleavage. Acceleration effect of oxidation and deceleration effect of secondary cracks combine affecting the crack propagation rate; when R is 0.5 or 0.06, those two seem equal and the effect of temperature is not obvious, while R is -1, more and deeper secondary cracks caused by fully interaction of high temperature and fatigue load make crack propagation rate at high temperature lower than that at room temperature.
Delamination Behavior of an Advanced Al-Li Alloy Laminate during Fatigue Crack Growth
Xiao HUANG, Yi HUANG, Jianzhong LIU
2018, 38(4): 130-136.   doi: 10.11868/j.issn.1005-5053.2018.000050
[Abstract](48) [FullText HTML](31) [PDF 839KB](4)
The delamination shape and size of fiber metal laminate are the key factors to study the fatigue crack growth behavior. To study delamination behavior of an advanced Al-Li alloy laminate during fatigue crack propagation process, the relation of the delamination size between the region with nearly 0 strain on the surface of specimen and the delamination region was obtained by finite element method. The strain data from digital image correlation (DIC) was correlated with the true delamination data. The method was proved by experimental data of delamination under different lay-up structures, saw-cut lengths and crack lengths; and the real-time monitoring of delamination behavior of the advanced Al-Li alloy laminate during fatigue crack growth was realized. The results show that this method has excellent applicability, economy and data consistency.
Interfacial Fracture Toughness of Carbon Fiber Reinforced Composites
Zonghong XIE, Shujie CAI, Qi GUO, Xiang LI
2018, 38(4): 137-142.   doi: 10.11868/j.issn.1005-5053.2016.000189
[Abstract](98) [FullText HTML](65) [PDF 705KB](7)
Interfacial fracture toughnesses of composite Mode I and Mode Ⅱ were investigated by double cantilever beam (DCB) and end notch bending (ENF) test. Using stereo microscope to record crack tip and CCD camera position to observe the evaluation of lesion, the phenomenon of matrix cracking and layer extension were analyzed, and the characteristics of interlayer fracture were studied. The effect of curing method on fracture toughness was analyzed through contrast experiment. The results show that crack propagation process is not stable and the load fluctuates up and down with the increase of displacement and crack length in fracture toughness test of Mode I , while the crack produced in fracture toughness test of Mode Ⅱ does not extend initially and the load increases linearly with the displacement. When the load approaches the critical load Pc, the crack propagates unsteadily along the layer and the load drops sharply. Fracture toughness of Mode I material prepared by autoclave curing is 43% more than that of the material prepared by hot-bonder curing, while fracture toughness of Mode Ⅱ material prepared by autoclave curing is 19% more than that of material prepared by hot-bonder curing.
Microstructures and Properties of FGH96/DD6 Joints Brazed at Vacuum Pressure State
Wenjiang ZOU, Bo CHEN, Yaoyong CHENG, Wei MAO, Huaping XIONG
2017, 37(4): 14-18   doi: 10.11868/j.issn.1005-5053.2016.000227
[Abstract](74) [FullText HTML](47) [PDF 1576KB](0)
2016, 36(4): 0-0  
[Abstract](82) [PDF 873KB](1)
Study of Catalysis Effect of Ni on CVI PyC Process
XU Piao, CHENG Lai-fei, ZHANG Li-tong, XU Yong-dong, TONG Chang-qing
2008, 28(1): 9-12,17  
[Abstract](62) [PDF 645KB](0)
Rheological behavior of Al2O3 aqueous neutral suspensions
TONG jian-feng, CHEN daming
2002, 22(1): 54-57  
[Abstract](59) [PDF 1036KB](0)
Effects of Rolling Process on Microstructure and Properties of Ti600 Alloy Plates
HONG Quan, QI Yun-lian, LIU Xiang, ZHAO Yong-qing
2006, 26(5): 31-34  
[Abstract](60) [PDF 447KB](0)
Prediction of the Effective Permittivity and Permeability of Magnetically Material Fiber with Resin
GAO Zheng-ping, BI Zhao-yi, WANG Xiao-hong
2007, 27(5): 83-90  
[Abstract](53) [PDF 950KB](0)
Fabrication of High Nb Containing TiAl Alloys by High-Energy Ball Milling and Pressureless Sintering
LU Xin, HE Xin-bo, QU Xuan-hui
2009, 29(1): 16-21  
[Abstract](44) [PDF 1598KB](0)
Microstructures and mechanical properties of carbon fiber reinforced silicon oxycarbide composites fabricated via hot-pressing assisted pyrolysis of polysiloxane
MA Qing-song, CHEN Zhao-hui, ZHENG Wen-wei, HU Hai-feng
2004, 24(5): 26-30  
[Abstract](82) [PDF 775KB](0)
Recent development on surface decoration of carbon nanotubes
CAO Mao-sheng, QIU Cheng-jun, ZHU Jing
2003, 23(4): 59-62  
[Abstract](47) [PDF 174KB](0)
Study of Relationship between Structures and Mechanical Properties of Three-Dimensional Angle-Interlock Woven Carbon/Resin Composites
YANG Cai-yun, LI Jia-lu, CHEN li, ZHANG Guo-li
2006, 26(5): 51-55  
[Abstract](52) [PDF 1048KB](0)
Effect of Rare Earth Y on Microstructure and Properties of Sn-58Bi Solder Alloy
Liukui GONG, Jinfa LIAO, Jihui YUAN, Guihe LI, Huiming CHEN
2018, 38(4): 101-108   doi: 10.11868/j.issn.1005-5053.2018.000007
[Abstract](220) [FullText HTML](83) [PDF 3220KB](21)
Effect of Mo content on Microstructure and Mechanical Properties of IN718 Alloy
Dawei HAN, Wenru SUN, Lianxu YU, Fang LIU, Bin ZHANG, Zhuangqi HU
2018, 38(4): 64-74   doi: 10.11868/j.issn.1005-5053.2018.000025
[Abstract](125) [FullText HTML](90) [PDF 1652KB](19)
Research Progress and Application Perspectives of 4D Printing
Ya'nan WANG, Fanghui WANG, Zhongming WANG, Jianjun LIU, Hong ZHU
2018, 38(2): 70-76   doi: 10.11868/j.issn.1005-5053.2018.001005
[Abstract](114) [FullText HTML](48) [PDF 2468KB](15)
Research Progress in Preparation and Crystallization Technologies of Amorphous ITO Film
Jiaming LI, Liangbao JIANG, Mu CHEN, Xiaoyu LI, Youxiu WEI, Xiaofeng ZHANG, Yibo MA, Yue YAN
2018, 38(5): 1-12   doi: 10.11868/j.issn.1005-5053.2017.000035
[Abstract](117) [FullText HTML](73) [PDF 851KB](15)
Effect of Hot Deformation on PPB Precipitations and Microstructure in P/M Superalloy FGH96
Changkui LIU, Zhenwei WEI, Jiaqing ZHANG, Zhen ZHENG
2018, 38(3): 40-45   doi: 10.11868/j.issn.1005-5053.2017.000207
[Abstract](163) [FullText HTML](75) [PDF 4881KB](14)
2018, 38(3): 1-2  
[Abstract](133) [FullText HTML](94) [PDF 1077KB](13)
Research Process in Plasma Spray Physical Vapor Deposited Thermal Barrier Coatings
Jia SHI, Liangliang WEI, Baopeng ZHANG, Lihua GAO, Hongbo GUO, Shengkai GONG, Huibin XU
2018, 38(2): 1-9   doi: 10.11868/j.issn.1005-5053.2018.001008
[Abstract](305) [FullText HTML](142) [PDF 3912KB](13)
Progress in Amorphous Transparent Conducting Oxide Thin Films
Xiaofeng ZHANG, Yue YAN, Mu CHEN, Hongyan LIU, Changshan HAO, Guanli ZHANG
2018, 38(1): 1-16   doi: 10.11868/j.issn.1005-5053.2017.000042
[Abstract](121) [FullText HTML](38) [PDF 5399KB](12)
Novel Ceramic Materials for Thermal Barrier Coatings
Zhaolu XUE, Hongbo GUO, Shengkai GONG, Huibin XU
2018, 38(2): 10-20   doi: 10.11868/j.issn.1005-5053.2018.001001
[Abstract](144) [FullText HTML](61) [PDF 2249KB](12)
Research Progress of Metal-Intermetallic Laminated Composites
Fantao KONG, Wei SUN, Fei YANG, Xiaopeng WANG, Yuyong CHEN
2018, 38(4): 37-46   doi: 10.11868/j.issn.1005-5053.2017.000204
[Abstract](110) [FullText HTML](73) [PDF 2452KB](10)
High Temperature Titanium Alloys:Status and Perspective
WANG Qing-jiang, LIU Jian-rong, YANG Rui
2014, 34(4): 1-26   doi: 10.11868/j.issn.1005-5053.2014.4.001
[Abstract](180) [PDF 9215KB](10)
Effect of Cryomilling on Microstructure and Mechanical Properties of 7050 Aluminum Alloy
Haiping ZHANG, Xudong WANG, Jiongli LI, Tianbing HE, Zhen CAO, Junzhou CHEN
2018, 38(3): 20-25   doi: 10.11868/j.issn.1005-5053.2018.000030
[Abstract](105) [FullText HTML](66) [PDF 2148KB](10)
Additive Manufacture of Metamaterials: a Review
Lei ZHANG, Linrong ZHUO, Guiping TANG, Bo SONG, Yusheng SHI
2018, 38(3): 10-19   doi: 10.11868/j.issn.1005-5053.2018.001009
[Abstract](102) [FullText HTML](60) [PDF 2130KB](10)
Research Progress on Deployable Structures of Shape Memory Polymer Composites
Tianning REN, Guangming ZHU, Jing NIE
2018, 38(4): 47-55   doi: 10.11868/j.issn.1005-5053.2017.000159
[Abstract](107) [FullText HTML](83) [PDF 912KB](9)
Preparation and Cryogenic Properties of Cyanate Ester Resin Blends Co-modified by Phenoxy Resin/Epoxy Resin
Haiqi ZHANG, Guan WANG, Tangling GAO, Gang FU, Jianwei WU, Hong KUANG, Chunming FU
2018, 38(3): 83-90   doi: 10.11868/j.issn.1005-5053.2017.000130
[Abstract](83) [FullText HTML](52) [PDF 2270KB](9)
Effect of SPS Sintering Temperature on Properties of ZrB2-SiC Ceramic
Qi LI, Fengwei GUO, Lamei CAO, Xiaosu YI
2018, 38(4): 87-92   doi: 10.11868/j.issn.1005-5053.2017.000082
[Abstract](66) [FullText HTML](60) [PDF 807KB](9)
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