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A R Mirhabibi - One of the best experts on this subject based on the ideXlab platform.
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the effect of applied pressure on fracture surface and tensile properties of Nickel coated continuous carbon fiber reinforced aluminum composites fabricated by squeeze casting
Materials & Design, 2010Co-Authors: E Hajjari, Mohammad Divandari, A R MirhabibiAbstract:Composite specimens were consolidated using squeeze casting method under 30, 50 and 70 MPa applied pressures. Nickel coated polyacrylonitrile (PAN) based carbon fibers with a mean volume fraction of about 20% were used as reinforcement and the effect of applied pressure and Coating layer were evaluated by studying the microstructure, fracture surface and tensile properties of the composite samples. The results indicate that presence of Nickel Coating on the carbon fibers improves the tensile strength of the composites, significantly. This seems to be the result of the effect of Nickel layer on improving the wettability and also protecting the fibers against reaction with liquid aluminum during processing the composite. The appropriate applied pressure for preparing the composite samples was achieved to be about 30 MPa. Higher pressures demonstrated damage in distribution of the fibers and also caused separation of Nickel Coating layer.
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the study of electroless Coating of Nickel on carbon fibers
2004Co-Authors: A R MirhabibiAbstract:The continuity and thickness of the Coating layer, are the most important factors in wet- ting properties and strength of carbon fibers. These factors are crucial in the quality of metal matrix composites made with carbon fibers. In this research the Polyacrylonitrail base carbon fibers have been Nickel coated with 0.2, 0.5, 0.8 and 11 µ m thickness, by the electroless method. The effect of the thickness of Nickel Coating on surface condition and also the tensile strength of the carbon fibers has been investigated. The study of surface condition of the coated carbon fibers by SEM showed that the Nickel Coating at the thickness of about 0.5 µm has the best continuity on the carbon fibers. The results of tensile tests of carbon fibers coated with different thickness of Nickel showed that increasing the thickness of Coating layer decreases the overall strength of fibers.
Sham-tsong Shiue - One of the best experts on this subject based on the ideXlab platform.
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effect of the Coating thickness and roughness on the mechanical strength and thermally induced stress voids in Nickel coated optical fibers prepared by electroless plating method
Thin Solid Films, 2005Co-Authors: Sham-tsong Shiue, Chiahao Yang, Tsongjen YangAbstract:The effect of the Coating thickness and roughness on the mechanical strength and thermally induced stress voids in Nickel-coated optical fibers is theoretically and experimentally investigated. Seven samples of Nickel-coated optical fibers with identical fiber length but different Coating thickness are prepared using electroless plating method. The thickness of the Nickel Coating is controlled by the plating time, with the thicknesses being 35, 65, 119, 218, 308, 419 and 565 nm, respectively. The mechanical and thermal stresses in these Nickel-coated optical fibers are analyzed. The atomic force microscope measurement reveals that the roughness of the Nickel Coating is unchanged when the Coating thickness is not larger than 65 nm. However, as the Coating thickness is not less than 65 nm, the Coating roughness increases with increasing the Coating thickness. To increase the tensile strength of the Nickel-coated optical fiber, the Coating thickness should be not less than 65 nm, and the surface roughness of the Nickel Coating should not exceed 2.93 nm. Alternatively, if the Coating thickness is in the range of 35 to 218 nm, thermally induced stress voids are less found in the Nickel Coatings. However, if the Coating thickness is in the range of 308 to 565 nm, the number of thermally induced stress voids increases with increasing the Coating thickness. To minimize these voids, the surface roughness of the Nickel Coating should also be decreased.
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Effect of the Coating thickness and roughness on the mechanical strength and thermally induced stress voids in Nickel-coated optical fibers prepared by electroless plating method
Thin Solid Films, 2005Co-Authors: Sham-tsong Shiue, Chia H. Yang, Rong Shian Chu, Tsong J. YangAbstract:The effect of the Coating thickness and roughness on the mechanical strength and thermally induced stress voids in Nickel-coated optical fibers is theoretically and experimentally investigated. Seven samples of Nickel-coated optical fibers with identical fiber length but different Coating thickness are prepared using electroless plating method. The thickness of the Nickel Coating is controlled by the plating time, with the thicknesses being 35, 65, 119, 218, 308, 419 and 565 nm, respectively. The mechanical and thermal stresses in these Nickel-coated optical fibers are analyzed. The atomic force microscope measurement reveals that the roughness of the Nickel Coating is unchanged when the Coating thickness is not larger than 65 nm. However, as the Coating thickness is not less than 65 nm, the Coating roughness increases with increasing the Coating thickness. To increase the tensile strength of the Nickel-coated optical fiber, the Coating thickness should be not less than 65 nm, and the surface roughness of the Nickel Coating should not exceed 2.93 nm. Alternatively, if the Coating thickness is in the range of 35 to 218 nm, thermally induced stress voids are less found in the Nickel Coatings. However, if the Coating thickness is in the range of 308 to 565 nm, the number of thermally induced stress voids increases with increasing the Coating thickness. To minimize these voids, the surface roughness of the Nickel Coating should also be decreased. ?? 2005 Elsevier B.V. All rights reserved.
Yichun Zhou - One of the best experts on this subject based on the ideXlab platform.
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A novel blister test to evaluate the interface strength between Nickel Coating and low carbon steel substrate
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: L.h. Xiao, Xu Ping. Su, J.h. Wang, Yichun ZhouAbstract:Abstract A novel blister test theory model was developed based on the bending theory of beams for assessing the interface strength of the Nickel Coating/low carbon steel substrate material system. The strain energy of the debonded Nickel Coating was calculated analytically and by finite element analysis, respectively. The analytic solutions agree well with the FE calculation results. Some blister tests were carried out on the WII-5 Computer Controlled Material Mechanical Properties Testing Machine, using four Nickel-coated specimens type-A, -B, -C and -D which were electrodeposited on low carbon steel substrate. Here, types A, B, C and D correspond to the Nickel Coating thickness of 5 μm, 10 μm, 15μm and 25μm, respectively. The interface strength, evaluated by this blister test method, is 196.86 J/m2 and 269.40 J/m2 for type-C and -D specimens, respectively. However the tests demonstrate that the type-A and -B specimens were cut through by the spindle and no delaminations between the Coating and the substrate could be found.
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Forming limits of Nickel Coating on right region
Transactions of Nonferrous Metals Society of China, 2007Co-Authors: Li-qun Zhou, Yu-ping Li, Yichun ZhouAbstract:The forming limits of Nickel Coating on the right region were studied, so as to direct the preparation of the material and help the production of workpieces. The electrodeposited Nickel Coating was prepared on steel substrate to form advanced structures, and its plastic instability was investigated by the Swift Plastic Instability Theory. By using the compound law for laminated sheet metals, explicit equations for the calculation of the instable eigen values were deduced. The forming limit diagrams of the Nickel Coating on the right region were plotted. It is exhibited that the forming limit of the Coating sheet is between the forming limits of the individual Nickel Coating and steel substrate. The forming limit of the Nickel Coating is not so good as that of the steel substrate, and the forming limit strain of the Coating sheet tends to diminish with the increase of thickness of the Coating. The greater the normal anisotropic coefficient of the materials is, the better the forming limit is.
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Computation of deformation-induced textures in electrodeposited Nickel Coating
Transactions of Nonferrous Metals Society of China, 2006Co-Authors: Shiguo Long, Yichun ZhouAbstract:The deformation-induced textures in electrodeposited Nickel Coating were numerically studied. The finite element method (FEM) for polycrystalline was developed based on Taylor model. Then the deformation-induced textures in electrodeposited Nickel Coating with initial random and lamellar texture were simulated under tensile load. It is found that the initial textures significantly influence the deformation-induced textures. For Nickel Coating with the initial random textures, when the tensile strain is about 40%, there are some lamellar textures. For Nickel Coating with the initial lamellar textures, the lamellar texture is more intensity with the increase of the tensile strain. With the increase of the tensile strain in the Coating, there are more pronounced element distortion and a more inhomogeneous deformation. Due to the different crystal orientations, the grain-scale roughness is observed. With increasing tensile strain in the Coating, the surface grain-scale roughness increases on the free surface. The surface roughness of the Coating with initial random texture is lower than that with the initial lamellar texture.
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Forming limit of electrodeposited Nickel Coating in the left region
Journal of Materials Engineering and Performance, 2006Co-Authors: L. Q. Zhou, Y. P. Li, Yichun ZhouAbstract:A uniform Nickel (Ni) Coating was bilaterally electrodeposited on the low-carbon steel substrate for the application of advanced battery shells. Its forming limit was investigated by Hill localized necking theory coupled with finite element simulation and scanning electron microscopy. The effective stress and effective strain in the Ni Coating and steel substrate are deduced using Hill’s anisotropic yield function. The localized necking condition is derived by sandwich sheet analysis, and the forming limit strains are obtained by solving the nonlinear equation of the localized necking condition. Extensive calculations are carried out using the proposed model. This study exhibits the Nickel Coating thickness and the normal anisotropic coefficients of the Coating and substrate have little influence on the forming limit curve (FLC) in the left region of the coated sheet, but the strain hardening exponents of the Coating and substrate have much effect on it. The calculated result matches well with the measured data in uniaxial tension. This investigation is useful for the preparation of the electrodeposited Ni Coating and helpful for the forming operation of the battery shells.
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Residual Stress and Stress-Strain Relationship of Electrodeposited Nickel Coatings
Advanced Materials Research, 2005Co-Authors: Yichun Zhou, Y.p. JiangAbstract:The uniform Nickel Coatings on substrate of low carbon steel were prepared by an electrodeposition method. The residual stress in the electrodeposited Nickel Coating was measured by X-ray diffraction (XRD). It was tensile when the Coating was not treated. Laser beam thermal shock was used to modify the mechanical properties of the Nickel Coating. Laser beam thermal shock could redistribute the residual stress in the Nickel Coating. The residual stress could be converted from tensile to compressive. A tensile method to determine the stress-strain curve of the Coating is proposed where the stress-strain relationship of the substrate without Coating was determined for the specimen loaded by an applied tensile force.
Zhou Liqun - One of the best experts on this subject based on the ideXlab platform.
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Interface feature of electrodeposited Nickel Coating steel plate in stamping process
Forging and Stamping Technology, 2010Co-Authors: Wang Hanyu, Zhou LiqunAbstract:ABAQUS was used to simulate the stamping process for electrodeposited Nickel Coating plate.In the simulation,a built-in Cohesive zone model of ABAQUS was used to present electrodepsited Nickel Coating steel's interface performance.The computational results show that,at the interface,the normal stress is between-113.765-3 MPa and the maximum tangential stress is 50 MPa,and the maximum interface stress is at the die fillet during the process of stamping.Finally the case of delamination was analyzed by changing blankholder force,clerance between punch and die,friction faltor,and tool radii.This method can be used as a guidance for shell's forming manufactue.
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Mechanical Model and Simulation of Electrodeposited Nickel Coating Steel Interface
Mechanical Engineer, 2009Co-Authors: Zhou LiqunAbstract:A built-in cohesive zone model of ABAQUS was used to present electrodepsited Nickel Coating steels interface performance,and studied the calculation interface model and damage criterion based on traction- separation law. The peeling and debonding process of interface structure were simulation which describes interface mechanical performance。 The strength curves were gained for interface damages of the electrodeposited Nickel Coating steel.As is shown, the results are acceptable, so this method can be used as guidance for shell’s forming manufactue.
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Interface Performance of Electrodeposited Nickel Coating in Stamping Process
Materials for Mechanical Engineering, 2006Co-Authors: Zhou LiqunAbstract:Finite element method was used to simulate the stamping process for electrodeposited Nickel Coating by using a plane model.The stress and strain fields at the interface were obtained within the Nickel Coating and steel Substrate.The computational results shows that the value and property for the stress at the interface were variational.Generally,the normal stress was between—50～50 MPa,and the shear stress is between—40～30 MPa.The strain in the Nickel Coating might he much greater than in the substrate.But they were approximately matchable during the stamping process.
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Preparation and Shock Properties of Electrodeposited Nickel Coating
Materials protection, 2004Co-Authors: Zhou Liqun, Zhou YichunAbstract:Electrodeposition method was introduced to prepare Nickel Coating on low carbon steel sheet. Shock properties of electrodepositing Nickel Coating with thickness of 3~6 μm were studied. The electrolyte was sulfate solution, and the coated sheet was processed by vacuum heat treatment to form a transition layer in the interface between the Ni Coating and substrate. The carbon steel specimens with electrodeposited Nickel Coating were impacted by flat and tapered projectiles in a 57 canon barrel, and then the impacted surface and interface were observed by SEM. The impact process was analyzed using shock wave theory. The experimental results show that neither damage/spall in the surface of electrodeposited Nickel Coating nor crack in the interface occur after impacted, the properties of Ni Coating under dynamic load are better than imported material SPCE. The experiments exhibit that the Nickel electrodeposited steel sheet has good interface strength and toughness, which offers attractive potential for advanced structural applications.
Tsongjen Yang - One of the best experts on this subject based on the ideXlab platform.
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effect of the Coating thickness and roughness on the mechanical strength and thermally induced stress voids in Nickel coated optical fibers prepared by electroless plating method
Thin Solid Films, 2005Co-Authors: Sham-tsong Shiue, Chiahao Yang, Tsongjen YangAbstract:The effect of the Coating thickness and roughness on the mechanical strength and thermally induced stress voids in Nickel-coated optical fibers is theoretically and experimentally investigated. Seven samples of Nickel-coated optical fibers with identical fiber length but different Coating thickness are prepared using electroless plating method. The thickness of the Nickel Coating is controlled by the plating time, with the thicknesses being 35, 65, 119, 218, 308, 419 and 565 nm, respectively. The mechanical and thermal stresses in these Nickel-coated optical fibers are analyzed. The atomic force microscope measurement reveals that the roughness of the Nickel Coating is unchanged when the Coating thickness is not larger than 65 nm. However, as the Coating thickness is not less than 65 nm, the Coating roughness increases with increasing the Coating thickness. To increase the tensile strength of the Nickel-coated optical fiber, the Coating thickness should be not less than 65 nm, and the surface roughness of the Nickel Coating should not exceed 2.93 nm. Alternatively, if the Coating thickness is in the range of 35 to 218 nm, thermally induced stress voids are less found in the Nickel Coatings. However, if the Coating thickness is in the range of 308 to 565 nm, the number of thermally induced stress voids increases with increasing the Coating thickness. To minimize these voids, the surface roughness of the Nickel Coating should also be decreased.