航空材料学报

2019, 39(6): 1-2.

[Abstract](2833) [FullText HTML] (1339) [PDF 1129KB](31)

Abstract:

Resent development in high-entropy alloys and other high-entropy materials

Xiaopeng WANG, Fantao KONG

2019, 39(6): 1-19.

[Abstract](11652) [FullText HTML] (4725) [PDF 1396KB](1248)

Abstract:
High-entropy (HE) materials are defined as novel multi-principal materials that contain several principal elements (usually ≥ 5) in an (equa) equi-molar ratio, and the design concept of HE materials introduces a new way to improve the properties of materials. Due to their unique crystallographic structure characteristics, HE materials show many different characteristics of microstructures and properties compared with conventional materials .The HE materials have great potential applications in many fields. At present, many kinds of high-entropy materials were prepared with excellent properties in mechanics, physics or chemistry, such as high strength and elongation, distinguished thermal stability, wear resistance, magnetic, conductivity and corrosion resistance. This paper reviews the recent research and development of high-entropy alloys, high-entropy ceramics and high-entropy intermetallics, and summarizes their structure characteristics, microstructures, properties and strengthening mechanisms. In the future, high throughput calculation and preparation will be an important and fast way to design this kind of multi-component materials. With the development of materials, the forming and processing technologies of high entropy materials will develop rapidly to meet their diversified application needs.

Research progress of green self-assembled anti-corrosion film on metal surface

Xiangyu CAO, Juan DU, Ziming YANG, Hanqing YANG, Boyang LI, Hailong LI

2019, 39(6): 20-31.

[Abstract](2956) [FullText HTML] (1391) [PDF 22114KB](28)

Abstract:
The application of self-assembled membrane technology in metal surface corrosion protection is more and more extensive. Using simple and effective membrane technology to prepare green and environment-friendly membrane products has become a research hotspot in the field of anti-corrosion membrane. In this paper,the research progress of metal surface self-assembled film preparation technology is summarized.Taking the metal surface self-assembled monolayer membrane and its composite membrane as the research object, the classification, characteristics, applications and anti-corrosion mechanism, etc.of self-assembled membrane technology on the surface of aluminum/aluminum alloy, copper, copper alloy, stainless steel and other active metals are expounded respectively.It is pointed out that the research on the interface bonding between membrane and substrate, mechanism of film formation, mechanism of corrosion protection and so on is not perfect yet, which is still a scientific problem to be solved urgently.

Research progress and perspective trend of drilling technology for carbon fiber reinforced polymer

Pengqiang FU, Yinhong JIANG, Yiwen WANG, Chengyang XU, Lijie ZHOU

2019, 39(6): 32-45.

[Abstract](3337) [FullText HTML] (1543) [PDF 1324KB](62)

Abstract:
Carbon fiber reinforced polymer (CFRP) has been widely used in the aviation, space and automobile structural parts manufacturing due to its excellent physical and mechanical properties. However, the properties of CFRP materials with inhomogeneity and anisotropy are vastly different from metals. In the process of drilling, it is easy to produce delamination, tearing, burr and other defects, which seriously affect the quality of drilling. Therefore, drilling technology of CFRP-metal stacks has become a difficult problem in aircraft assembly process. This paper summarizes the researches of drilling mechanism of CFRP in recent years. The relationship between chip formation mechanism and fiber orientation angle is generalized. Meanwhile, the relationship between axial drilling force, drilling temperature and tool shape, workpiece material, process parameters is summarized. The causes, detection, evaluation methods and restraining measures of typical machining damage during CFRP drilling processes, such as delamination, burr and tearing are analyzed. The latest advances in material, geometric structure of CFRP drilling tools, and development of simulation technology of CFRP drilling process are expounded. It is also proposed that the establishment of accurate and reliable constitutive model is the key to the research of drilling simulation technology. The development trend of CFRP drilling technology is prospected by introducing new CFRP drilling technologies, such as variable process parameters drilling, robotic automatic drilling and suction-type internal chip removal drilling.

Research progress of anodic electrochromic materials

Ziyi FU, Youxiu WEI, Weiming LIU, Mu CHEN, Yibo MA, Jiaming LI, Jiuyong LI, Yue YAN

2019, 39(6): 46-62.

[Abstract](6621) [FullText HTML] (3227) [PDF 1424KB](111)

Abstract:
Electrochromic technology has been widely used in many fields, such as building windows and car rear-view mirrors. Ion storage layers (generally anodic electrochromic materials) are significant for improving the performance of electrochromic devices and realizing the application of the technology. Its role is to store and supply the ions needed for the color change reaction, maintaining the charge balance of the entire electrochromic process. At present, the most typical anodic electrochromic material is nickel oxide(NiO). The cheap NiO film has high coloration efficiency and large range of optical transmittance, so it is widely used in the electrochromic technology. This paper overviews the research progress of anodic electrochromic materials in recent years, including material classification, working principle and characteristic requirement, and also introduces the film preparation methods. Developing simple and cost-effective film preparation process is the research focus of electrochromic technology. At the same time, some methods for improving the performance of anodic electrochromic materials, and prospects the development trend are introduced.

Modification and thermal analysis for curing properties of cyanate-ester resin

Haitao QIAO, Jianwen BAO, Xiangyu ZHONG, Lianwang ZHANG, Jiangpeng SONG

2019, 39(6): 63-72.

[Abstract](3093) [FullText HTML] (1462) [PDF 707KB](64)

Abstract:
From an engineering practical perspective, modification, thermal analysis for curing properties of cyanate ester resin, as well as development of adhesives and composites based on cyanate ester resin are reviewed. Modification of cyanate involves toughening by rubbers or thermoplastics, synergistic modification with epoxy and bismaleimide, and so on. The adhesive development examination results show that the satisfied lap shear strength and peel strength are gained by using hydroxyl-terminated poly (ether sulfone) (PES-OH), and moreover, relative lower dielectric constant and lower loss tangent are maintained. Although the strength can be improved by adding epoxy, such kind adhesive composition still has relative poor electrical properties. The developed cyanate adhesive SY-CN has higher lap shear strengths up to 30 MPa at temperatures below 175 ℃, lower dielectric loss of 0.0065, unchanged strength level after 200 hours of hot-aging at 200 ℃, and satisfied anti-peel performance, e.g. sandwich honeycomb climbing drum peel strength is up to 83.2 N•mm/mm. More and more studies on cure kinetic thermal analysis have indicated that the increase or decrease in curing activation energy data of modified cyanate ester resin versus unmodified cyanate ester resin can be synchronized with up or down of maximum cure peak temperature from the differential scanning calorimetry (DSC) curves, and also can be changed oppositely. Cyanate ester resin modified with hydroxyl-terminated poly (ether sulfone) (PES-OH) has lower maximum cure peak temperature of about 20 ℃ reduction versus unmodified cyanate, but the curing activation energy increase which can be due to change of reaction mechanism and steric hindrance effect. Based on change of maximum cure peak temperatures (T_p) with different heating rate data (ϕ) from DSC curves, a linear equation of T_p = T₁ + ΔT ln ϕ has been established, then, the curing temperature parameter can be more reasonably determined.

Effect of Ni content on microstructure and properties of Co-based superalloys

Pengjie ZHOU, Dehang SONG, Haibin WU, Xinkang GAO, Ueshima NOBUFUMI, Oikawa KATSUNARI

2019, 39(6): 73-80.

[Abstract](2453) [FullText HTML] (1446) [PDF 3359KB](40)

Abstract:
Co-based superalloys casting ingots were prepared by vacuum smelting furnaces, and the influence of Ni content on the microstructure and lattice misfit of Co-based superalloys were studied by X-ray diffraction analysis (XRD) and scanning electron microscope (SEM). The effect of Ni content on the properties of Co-based superalloys was studied by high temperature compression test. The results show that the average size of the γ′ phase increases with the increment of Ni content. When the Ni content rises from 0% to 15%, the volume fraction of the γ′ phase in the alloy increases gradually, which peaks at 15% Ni content.After that the volume fraction of the γ′ phase decreases slightly when the Ni content increases to 20%.When the Ni content increases from0 to 10%, the lattice misfit between γ/γ′ phase decreases.While the misfit of the γ/γ′ phase increases slightly when the Ni content raises to 20%.The Ni content increases from 10% to 15%, the lattice misfit of the γ/γ′ phase begins to decreases again. Through the test of high temperature compression of the alloy, the yield strength of the alloy with 5% Ni content is the highest.

Analysis on thermal stress and heat conduction of functionally graded cylindrical shell

Wenguang LIU, Xiayao FENG, Wan YAO

2019, 39(6): 81-89.

[Abstract](3028) [FullText HTML] (1441) [PDF 1023KB](27)

Abstract:
Ceramic-metal based functional graded materials (FGMs) are expected to be used in the design of airplane tail nozzle, not only because of their material characteristics varies with the changing of thickness continuously, but also because of the speed of heat conduction of ceramic material in the inner ring and the high strength of metal in the outer ring. The purpose of this article is to discuss the impacts of different heat flux density, ceramic volume fraction index and temperature on the thermal stress and heat conduction of FGMs shell. Firstly, the physical property model of FGMs was set up, and the effects of different kinds of parameters on the thermal physical properties were discussed. Thereafter, the thermal stress equation of the FGMs cylindrical shell was derived, and the change law of thermal stress under different conditions was explored. In the end, the heat conduction equation of FGMs shell was derived by energy equilibrium theorem and the impacts of heat flux density on the heat conduction were discussed. Results indicate that the thermal stress increases slowly with the increasing of the ceramic volume fraction index when the heat flux density is constant. The stress in the outer side of the cylindrical shell is larger than that of the inner side. The temperature of an arbitrary section increases with the increasing of heat flux density. And the trend is more obvious as the heat flux density becomes bigger.

Effects of annealing process on morphology and mechanical properties of magnetron sputtered LiCoO₂ thin films

Yibo MA, Mu CHEN, Yue YAN, Xiaofeng ZHANG, Weiming LIU, Jiaming LI, Xuan ZHANG

2019, 39(6): 90-98.

[Abstract](2736) [FullText HTML] (1426) [PDF 1185KB](23)

Abstract:
LiCoO₂ thin films were prepared on single crystal Si (100) by magnetron sputtering method and then annealed by different annealing temperatures, holding times and atmospheres. The effects of annealing processes on the surface morphologies, compositions, crystal structures and mechanical properties of LiCoO₂ films were investigated. The results show that the surface average roughness of LiCoO₂ film is reduced from 11.63 nm to 6.13 nm; annealing atmosphere has the greatest influence on the surface morphologies of LiCoO₂ films. The LiCoO₂ film composition is destroyed due to Li₂O, CoO, Co₃O₄ by-products formed during annealing process. LiCoO₂ film are crystallized under any annealing conditions, the average grain size is about 30 nm, annealing temperature has the greatest influence on the grain size and residual stress. After annealing, the hardness and young's modulus of LiCoO₂ films are increased by an order of magnitude. Under the optimal annealing process (600 ℃, 60 min, pure O₂ atmosphere), the ratio of H³/E_r² is 0.03 GPa, which shows excellent resistance to plastic deformation.

2019 Vol. 39, No. 6