航空材料学报

2020, 40(6): .

[Abstract](501) [FullText HTML] (263) [PDF 2192KB](23)

Abstract:

2020, 40(6): 1-3.

[Abstract](416) [FullText HTML] (210) [PDF 328KB](14)

Abstract:

2020, (6): 1-2.

[Abstract](432) [FullText HTML] (233) [PDF 331KB](16)

Abstract:

Surface oxidation characteristics of nickel-base superalloy GH4169 powder

Lichong Zhang, Wenyong Xu, Zhou Li, Shuangxi Wang, Jiankun Shen, Liang Zheng, Guoqing Zhang

2020, 40(6): 1-7.

[Abstract](1124) [FullText HTML] (443) [PDF 761KB](65)

Abstract:
The effect of temperature on surface oxidation characteristics of nickel-base superalloy GH4169 powder was investigated by field emission scanning electron microscope (FE-SEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The results show that the surface of the GH4169 superalloy powder is partially oxidized at room temperature（RT）, and on the surface there are elemental states dominated by Ni, Cr, Ti and Nb, and hydroxide/oxide dominated by Ni(OH)₂, Cr₂O₃, TiO₂ and Nb₂O₅. With the temperature increasing (150～250 °C) , the peaks of Ni, Cr, Ti and Nb elements become weaker, the degree of oxidation is slightly increased and the surface of powder is partially oxidized. When the temperature reaches to 350 °C, the peaks of Ni, Cr, Ti, and Nb elements are all disappeared, and the surface of powder is fully oxidized. The oxide layer thickness is about 5 nm, and is mainly composed of Ni(OH)₂, Cr₂O₃, TiO₂and Nb₂O₅. The effect of temperature on oxidation characteristics of the GH4169 superalloy powder is significant, and the maximum treatment temperature of the GH4169 superalloy powder used for this study is no more than 250 °C exposed within 1 h under atmospheric conditions.

Evolution of γ′ phase in DD6 single crystal turbine blade

Yanpeng XUE, Liang YANG, Jian YU, Shizhong LIU, Jiarong LI

2020, 40(6): 8-15.

[Abstract](1130) [FullText HTML] (324) [PDF 1487KB](43)

Abstract:
The evolution rule of γ′ phase in typical cross sections of DD6 single crystal superalloy turbine blade was investigated experimentally by SEM. The results show that comparing with the as-cast microstructures, the γ′ phase sizes of typical cross sections in the interdendrite regions of the heat-treated turbine blade are obviously refined, the γ′ phase sizes of the interdendritic (ID) region and dendritic core (DC) tended to be the same, and the γ′ phase size dispersion tended to decrease, the γ′ phases cubed degree increased. The sizes of as-cast and heat-treated γ′ phase in the dendrite core and interdendritic region of each cross section of the blade follow the normal distribution law. The size of γ′ phase in the section of the heat-treated blade is smaller than that of the tenon, and the size of the γ′ phase in the middle of the section is larger than that of the leading edge and trailing edge.

Microstructure, strength and toughness of C/SiC composite modified by PIP-SiC matrix

Zhixin MENG, Yingying ZHOU, Yi Zhang, Yuanyuan LU, Laifei CHENG

2020, 40(6): 16-22.

[Abstract](1083) [FullText HTML] (371) [PDF 725KB](42)

Abstract:
The matrix of fiber bundle composite C/SiC was modified by the combination means of precursor infiltration and pyrolysis (PIP) and chemical vapor infiltration (CVI). The microstructure of SiC matrix fabricated by PIP (PIP-SiC), and the fracture morphologies of the unmodified and modified composites were observed. Meanwhile, the tensile properties of the unmodified and modified composites were tested. The results show that PIP-SiC matrix modification improves the modulus matching between the fiber and matrix of C/SiC composite, and effectively improves the strength, toughness and stability of C/SiC composite. The tensile strength of modified C/SiC composite is slightly higher than that of unmodified C/SiC composite. Furthermore, the Weibull modulus, elongation and fracture work of modified C/SiC composite are 22%, 28% and 20% higher than those of unmodified C/SiC composite, respectively. Meanwhile, the variation coefficient (CV) of tensile strength, elongation and fracture work of modified C/SiC composite is 15%, 12% and 5% lower than that of unmodified C/SiC composite.

Effect of structural parameters on the residual stress of Mo/8YSZ functionally graded thermal barrier coating prepared by plasma spraying

Ming PANG, Xiaohan ZHANG

2020, 40(6): 23-32.

[Abstract](862) [FullText HTML] (434) [PDF 914KB](20)

Abstract:
In order to break through the technical bottleneck of traditional Mo/8YSZ double- layer thermal barrier coating which is easy to peel off at high temperature, the influence of the thickness of matrix, bonding layer, transition layer and ceramic layer on the residual stress of Mo/8YSZ functional gradient thermal barrier coating were studied. The numerical model of plasma spraying Mo/8YSZ functional gradient thermal barrier coating was established by using ANSYS finite element software. In the model, the variation of material thermal and physical parameters with temperature was considered, and the influence of different substrate, bonding layer, transition layer and ceramic layer thicknesses on the residual stress of functional gradient thermal barrier coating was analyzed. The results show that the maximum radial residual tensile stress and maximum radial residual compressive stress decrease with the increase of substrate thickness. With the increase of the thickness of bond layer, transition layer and ceramic layer, the maximum radial residual tensile stress increases and the maximum radial residual compressive stress decreases. Residual compressive stress is the main form of axial residual stress, with the increase of substrate thickness, maximum axial residual compressive stress of coating decreases, and with the increase of bonding layer or transition layer thickness, the maximum axial residual compressive stress increases, however, the change of ceramic layer thickness does not obviously effect the maximum axial residual compressive stress. The effect of changing the thickness of adhesive layer on the interface residual compressive stress is more obvious. The influence of the thickness of the matrix on the interface residual stress between the matrix and coating is within a certain range. When the substrate thickness increases to 12 mm, with the increase of the substrate thickness, the variation difference of the radial residual stress between the substrate and coating interface decreases. With the increase of the substrate thickness, the transition point and stress transition point of the stress form gradually transfer to the upper part of the boundary between the substrate and coating. With the increase of the thickness of the bonding layer, transition layer or ceramic layer, the transition point and stress transition point of the stress form gradually transfer to the lower part of the central area of the interface between the substrate and coating. By designing the functional gradient thermal barrier coating and adjusting the structural parameters of the thermal barrier coating system reasonably, the residual stress and stress mutation of the spraying component can be further reduced and the bonding strength between the substrate and coating can be improved.

Research progress on preparation technology and failure mechanism of metal/ceramic laminated composites

Zhen ZHANG, Jiu ZHOU, Jie ZHOU, Jun ZHU, Anzhe WANG, Qi ZHOU

2020, 40(6): 33-44.

[Abstract](4833) [FullText HTML] (2308) [PDF 1766KB](77)

Abstract:
The metal/ceramic laminated composites prepared from the unique “brick + mud” structure of biomimetic shells have been proved to have better strength and toughness, and have gradually become the research focus at domestic and abroad. In this paper, the current research of Al-based, Ti-based, Ni-based and other common metal/ceramic laminated composites is introduced, and the characteristic and process of each method are analyzed. The failure modes such as crack deflection, multiple crack propagation and crack bridging in metal/ceramic laminated composites are commonly summarized. The interface bonding strength of metal/ceramic laminated composites can be increased by controlling interfacial reactions and improving interfacial wettability. Optimizing of the preparation process and understanding the failure mechanism are the basis of engineering application of metal-ceramic layered composite materials. The introduction of the computational science into the research of metal/ceramic interface and damage mechanisms is an effective way to realize the controllability of the whole preparation process, and the realization of large size and diversified shape of products is the key to its large-scale application and promotion.

Influence of hole cold expansion on fatigue resistance of 2024 aluminum alloy

Lianqing WANG, Jiang BIAN, Han ZHANG, Shengchuan WU

2020, 40(6): 45-51.

[Abstract](1288) [FullText HTML] (593) [PDF 1168KB](50)

Abstract:
The effect of stress concentration around the hole easily leads to fatigue failure of aircraft structures, and usually causes catastrophic accidents. In order to elucidate the influence of cold expansion on the fatigue life of AA2024-T351 specimens, fatigue tests of specimens before and after cold expansion were accomplished on high frequency fatigue test machine. Combining the finite element simulation with X-ray diffraction measurement, the evolution of residual stress around the hole was thus investigated. Meanwhile, scanning electron microscope (SEM) and transmission electron microscope (TEM) were employed to observe the fatigue fracture morphology, fatigue striation and microstructure characteristics, and to explore the influence of microstructure features on fatigue life. Research results show that the cold expansion with 0.4 mm can significantly improve the fatigue resistance of AA2024-T351 specimens, and the fatigue limit can be increased by about 42%.

Effect of flap peening on stress corrosion cracking resistance of 7B04-T6 alloy

Wang HE, Yanli WANG, Yanan WANG, Jinsheng LIU, Zhiguo TAN, Jian GAO

2020, 40(6): 52-58.

[Abstract](801) [FullText HTML] (340) [PDF 1176KB](34)

Abstract:
The flap peening method with two different shot peening intensities were used to strength the 7B04-T6 for studying the effect of shot peeing on the stress corrosion cracking resistance and mechanical properties of 7B04-T6. Comparative testing about surface roughness, surface residual stress, surface topography, constant load stress corrosion cracking experiment and static strength tensile experiment were performed, the fracture surfaces were observed with SEM. The results show that, shot peening has imparted a surface residual compressive stress of −350 MPa (0.1-0.2 A intensity) and −275 MPa (0.2-0.3 A intensity). The surface roughness has increased from R_a 0.9 μm to R_a 1.6 μm (0.1-0.2 A intensity) and R_a 1.8 μm (0.2-0.3 A intensity). The duration of stress corrosion cracking has extended with 11.3 times (0.1-0.2 A intensity) and 8.7 times (0.2-0.3 A intensity) in the 3%NaCl + 0.5%H₂O₂ solution and with an application of 350 MPa load. Shot peening has not influenced the ultimate strength and percentage reduction in area, but slightly decreased the yield strength with a value of 15 MPa.

Analysis of lightning ablation damage of composite laminates containing fasteners based on thermoelectric coupling model

Zezhong SHAN, Mingjun LUO, Xiang LU, Minghui Tian

2020, 40(6): 71-79.

[Abstract](959) [FullText HTML] (353) [PDF 1124KB](31)

Abstract:
In order to analyze the ablation damage law of composite laminates with fasteners subjected to the action of lightning current, the lightning finite element analysis model of fastener-containing laminates was constructed based on the principle of thermoelectric coupling, and the results of lightning ablation damage were analyzed and tested. The results compare the validity of the model. The ablation damage of fastener-containing laminates under different ratios of electrical conductivity, specific heat and thermal conductivity was analyzed. The variation of ablation damage area under different factors was summarized. The results show that the lightning ablation damage of the fastener-containing laminates compared with the fastener-free laminates is more threatening to the safety of civil aircraft. In addition, the electrical conductivity and specific heat of the laminate have a greater impact on the ablation area of the fastener-containing composite laminate. When the two factors are reduced, the ablation damage area will increase to a certain extent, while the thermal conductivity of laminates and fastener properties have little effect on the ablation damage area.

Electrothermal coupled analysis and experimental research of lightning damage of carbon fiber composites with fastener

Yu SHI, Bin DU, Leying LI, Qian LIU, Yushun ZHAO, Zhong FU

2020, 40(6): 80-89.

[Abstract](916) [FullText HTML] (338) [PDF 1250KB](31)

Abstract:
In order to study the lightning damage characteristics of CFRP with fastener, this paper established a three-dimensional finite element model of CFRP with fastener and CFRP without fastener, and analyzed the lightning damage morphology of CFRP through electrothermal coupling simulation by finite element software. The lightning current damage test was carried out and the damage characteristics of the two kinds of CFRP under different lightning current peaks were compared. The results show that when the peak value of lightning current is low, the surface damage degree of CFRP with fastener is lower than that of CFRP without fastener. As the peak value of the lightning current increases, the longitudinal damage of the CFRP with fasteners gradually increases along the carbon fiber, and eventually exceeds the CFRP without fasteners. In the experimental, when CFRP without fastener is struck by lightning, linear damage is appeared on the surface perpendicular to the direction of carbon fiber, but the linear damage of CFRP with fastener perpendicular to the direction of carbon fiber is not obvious.

Influence of curvature radius on manufacturing defect of composite component formed by autoclave

Xueming WANG, Shaoliang LI, Fuyuan XIE

2020, 40(6): 90-96.

[Abstract](795) [FullText HTML] (319) [PDF 786KB](29)

Abstract:
Defect information obtained by non-destructive identification for more than four thousand composite components fabricated by convex mould in autoclave molding was statistically analyzed in this paper. The correlated rules between curvature radius of composite component and manufacturing defect were revealed. By self-designed solid pressure distribution testing method, the pressure distribution in the interface between flexible mould and rigid convex mould was also measured. Furthermore, combined with stress analysis in corner section and defect micrograph, the forming mechanism of the defect was primarily analyzed. The process control measures to avoid manufacturing defect were given. The results indicate that the defect ratio and the size of delamination in corner section of composite component both decrease with the increase of the curvature radius of component. The thickness distribution tends to be thick in the corner and thin on both sides of flat part, which is related to the coupling action between percolation mechanism and shear flow mechanism and the uniformity of pressure distribution.

2020 Vol. 40, No. 6