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Transient Liquid Phase Bonding of Ni-base Single Crystal Superalloy
Transient Liquid Phase Bonding of Ni—base Single Crystal Superalloy

Wen LI,Tao JIN,Xiaofeng SUN,Yi GUO,Hengrong GUAN,Zhuangqi HU,

材料科学技术学报 , 2002,
Abstract: The Ni-base single crystal superalloy was bonded by the transient liquid phase (TLP) bonding, using a Nbbase flexiblemetal cloth as an insert alloy. TLP bonding of superalloy was carried out at 1473~1523 K for 0.5~24 h in vacuum.The 001] orientation of each test specimen was aligned perpendicular to the joint interface. The bonded region wasobserved by optical microscopy, and the microstructural and compositional analyses across the bonded interlayer wereperformed by using a scanning electron microscopy (SEM). The electron back scattering diffraction (EBSD) methodwas applied to determine the crystallographic orientation. The results indicated that the chemical homogeneity acrossalmost identical, while the bonded interlayer had almost matched the crystallographic orientation of the bondedsubstrates.
Influence of Crystal Orientation on the Morphology of a Single Crystal Superalloy during Directional Solidification
Guo HE,Jianguo LI,Xemin MAO,Hengzhi FU,

材料科学技术学报 , 1998,
Abstract: The solid-liquid(S/L) intedecial morphology of a single crystal superalloy DD8 has been in-vestigated. The evolutive behavior of cellular morphology with tilted preferred crystallographic orientation near cell-dendrite transition was dynamically observed, and the efFect of crystallo-graphic orientation on primary dendritic arm spacing has been examined. The experimental results show that for planar and cellular morphology no any S/L interfacial anisotropy exists,but near cell-dendrite transition, the S/L intedecial anisotropy appears and gives rise to the cellular crystal fingers tilted from thermal flow direction to preferred crystallographic orientation.The crystal fingers with their preferred orientation parallel to DS growth direction are more stable than that with tilted orientation. For the tilted fingers, the sudece on the side facing DS growth direction is less stable than that on the reverse side, the different stability on the two sides will lead to forming unsymmetrical dendritical microstructure. With the increase of tilted angle of preferred crystallographic orientation, the primary dendrite arm spacing decreases.
Crystallographic Orientation Influence on the Serrated Yielding Behavior of a Single-Crystal Superalloy  [PDF]
Mikael Segers?ll,Johan J. Moverare
Materials , 2013, DOI: 10.3390/ma6020437
Abstract: Since Ni-based single-crystal superalloys are anisotropic materials, their behavior in different crystal orientations is of great interest. In this study, the yielding behavior in both tension and compression for , ?and ?oriented materials at 500 °C has been investigated. The ?direction showed a serrated yielding behavior, a great tension/compression asymmetry in yield strength and visible deformation bands. However, the ?and ?directions showed a more homogeneous yielding, less tension/compression asymmetry in yield strength and no deformation bands. Microstructure investigations showed that the serrated yielding behavior of the ?direction can be attributed to the appearance of dynamic strain aging (DSA) and that only one slip system is active in this direction during plastic deformation.
Morphology and Microstructure of Sputtered Superalloy Coating
Bangjie XIA,Hanyi LOU,Lixin ZHANG,Corrosion Science Laboratory,

材料科学技术学报 , 1993,
Abstract: The morphology and microstructure of magnetron sputtered coating of superalloy K38G on cast al-loy K38G have been investigated by means of SEM, TEM and XRD. The results indicate that thesputtered coating is identical to the substrate in chemical composition but it is composed only of γphase without γ'. The sputtered superalloy coating presents columnar structure and the grain size isin the range of 20-100 nm. There are a great number of planar defects such as stacking faults andmicrotwins in the coating. The morphology and microstructure of the sputtered coating may haveclose relation to the remarkable increase of oxidation resistance of the coating.
HU Benfu LI Huiying WU Chengjian ZHANG Shouhua University of Science,Technology Beijing,Beijing,China Associate Professor,Deptof Material Science,Engineering,University of Science,technology Beijing,Beijing,China,
HU Benfu LI Huiying WU Chengjian ZHANG Shouhua University of Science and Technology Beijing
,Beijing,China Associate Professor,Dept.of Material Science and Engineering,University of Science and technology Beijing,Beijing,China.

金属学报(英文版) , 1991,
Abstract: The solidification microstructure and phase composition of Ni-base superalloy FGH95 pow-der with different mesh size have been investigated.The structure transition was found fromdendrite in major into cellular structure as the powder size reduces and the cooling rate in-creases.The predominant phase was identified as MC-type carbide,with differentmorphologies,which may be related to their composition and the condition ofsolidification.Minor phases,such as boride,Laves and primary γ' are also present as ac-companiments of the carbide.

Chen Lian,Liu Minzhi,

金属学报 , 1981,
Abstract: An investigation on the crystallographic orientation and elemental segregation of flakes (hairline cracks) has been carried out by means of etching method and electron optical techniques (SEM, TEM, EPMA and AES). The results obtained are as follow:(1) The microappearances of fracture surface of flakes are a mixed fracture mode of quasicleavages and intergranular tearing waves.(2) The direction of the crack propagation of flakes are mostly along {112} planes of ferrite. These planes are also quasicleavage facets. While the orientation of the dendritic surface of flakes are {111} planes.(3) There are positive segregations of P, Mn, Mo, Cr and Si on the fracture surface of flakes, among which the most one is phosphorus.
Frameworks with forced symmetry II: Orientation-preserving crystallographic groups  [PDF]
Justin Malestein,Louis Theran
Mathematics , 2013,
Abstract: We give a combinatorial characterization of minimally rigid planar frameworks with orientation-preserving crystallographic symmetry, under the constraint of forced symmetry. The main theorems are proved by extending the methods of the first paper in this sequence from groups generated by a single rotation to groups generated by translations and rotations. The proofs make use of a new family of matroids defined on crystallographic groups and associated submodular functions.
WANG Huaming ZHANG Jinghua TANG Yajun LI Ying''''ao HU Zhuangqi Institute of Metal Research,Academia Sinica,Shenyang,China,
WANG Huaming ZHANG Jinghua TANG Yajun LI Ying''''ao HU Zhuangqi Institute of Metal Research
,Academia Sinica,Shenyang,China

金属学报(英文版) , 1992,
Abstract: The microstructure of a rapidly solidified single crystal Ni-base superalloy treated bylaserglazing has been observed by TEM and STEM-EDAX techniques.Variousmorphologies of extraordinary flower-like MC carbide of TiC type were revealed in the nar-row interdendritic regions.While the superfine γ′ precipitate and higher density of dislocationwere found in the γ matrix.
Grain size reduction in the 713C nickel superalloy as a result of heat treatment  [PDF]
M.B. Lachowicz,M. Faryna,M. Podrez-Radziszewska
Archives of Foundry Engineering , 2011,
Abstract: The paper presents metallographic test results for the 713C nickel superalloy after heat treatment and crystallographic orientation analysis performed with the EBSD method. The 713C alloy was subjected to annealing in the temperature of 950 oC for 30 hours followed by aircooling. As a result of the applied heat treatment the local grain size reduction in the alloy was observed. It has been found that in the primary grains the new subgrains of different crystallographic orientation are created. Between the new grains and the primary grains the boundaries of high angle appear. Orientation change in the micro-areas is closely related to the carbides rebuilding and volume diffusion of elements dissolved in the γ - γ’ alloy matrix and the (NbTi)C carbides.
Research on Interlayer Alloys for Transient Liquid Phase Diffusion Bonding of Single Crystal Nickel Base Superalloy DD6  [PDF]
Qiuya Zhai, Jinfeng Xu, Tianyu Lu, Yan Xu
Journal of Materials Science and Chemical Engineering (MSCE) , 2014, DOI: 10.4236/msce.2014.29002
Abstract: Transient Liquid Phase Diffusion bonding (TLP bonding) is an effective method to achieve excellent joint of DD6, which is a new generation single crystal superalloy to manufacture aero-engine turbine blades. In this paper, the interlayer alloys for DD6 TLP bonding were designed. The alloy foils with thickness 40 μm ~ 60 μm, width 4 mm were prepared by using a single roller rapid solidification apparatus and the TLP bonding of DD6 was conducted. Then the joint microstructure and alloying elements diffusion behaviors were analyzed. The results indicate that microstructures of interlayer alloys prepared are fine and homogeneous, the melting point range of alloys from 1070°C to 1074°C and their melting temperature interval is merely 20°C, when the chemical composition of alloys are 1.5 ~ 2.0Cr, 3.2 ~ 4.0W, 3.7 ~ 4.5Co, 2.2 ~ 3.0Al, 0.7 ~ 1.0Mo, 3.2B, remain Ni (wt%). When the welding parameters are bonding temperature 1200?C, holding time 8.0 hour and welding pressure 0.3 MPa, the compacted joints obtained and the microstructure of TLP bonding seams were similar to base metal. The bonding joint is composed of weld center zone, isothermal solidification zone and diffusion-affected zone. Within joint, the elements diffusion is sufficient and borides in the diffusion zone are fewer.
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