The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Akio Hirose - One of the best experts on this subject based on the ideXlab platform.
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relationship between intermetallic compound layer thickness with deviation and interfacial Strength for dissimilar Joints of aluminum alloy and stainless steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Ryoichi Hatano, Tomo Ogura, Tomoki Matsuda, Tomokazu Sano, Akio HiroseAbstract:Abstract The relationship between the intermetallic compound (IMC) layer thickness including the deviation and Joint Strength was evaluated for the dissimilar Joints between aluminum alloys and austenitic stainless steel. To evaluate the interface with various IMC layer thicknesses, the Joints by friction stir welding were solution-heat-treated and artificially aged. The transitions of Joint Strength and fracture position were characterized for the IMC layer thickness ranging from 0 to 2.5 µm. Further, we demonstrated that the fracture position can be determined by the percentage of the joining area via the IMC layer thickness below a threshold value, which was 0.4 µm.
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Interfacial Microstructure and Joint Strength of Sn-Ag and Sn-Ag-Cu Lead Free Solders Reflowed on Cu/Ni-P/Au Metallization
2016Co-Authors: Akio Hirose, Tomoyuki Hiramori, Mototaka Ito, Yoshiharu Tanii, Kojiro F. KobayashiAbstract:Abstract. Sn-3.5Ag (Sn-Ag) and Sn-3.5Ag-0.75Cu (Sn-Ag-Cu) solder balls were reflowed on electroless Ni-P/Au plated Cu pad with varying thickness of Au layer (0 to 500nm). In the Sn-Ag solder Joint, a P-rich layer including voids, which resulted from Ni diffusion from the Ni-P plating to form Ni3Sn4 interfacial reaction layer, formed at the interface regardless of Au plating thickness. This caused the degradation of the Joint Strength. On the contrary, the Sn-Ag-Cu solder Joint had no continuous P-rich layer formed and showed a higher Joint Strength than the Sn-Ag solder Joint in the case of Au plating of 50nm or less. Cu alloying to the solder promote the formation of (Cu, Ni)6Sn5 instead to Ni3Sn4 as the interfacial reaction layer. The (Cu, Ni)6Sn5 reaction layer can suppress the diffusion of Ni from the N-P plating and thereby inhibit the formation of the P-rich layer. However, in the case of thick Au plating of 250nm or more, a thin P-rich layer formed at the interface even in the Sn-Ag-Cu solder Joint and the Joint Strength was degraded. Au dissolving into the solder from the Au plating during the reflow process may encourage the diffusion of Ni from the Ni-P plating into the solder. As a result, the Sn-Ag-Cu solder Joints with 50nm Au coating provided the best Joint Strength, although its Joint Strength considerably degraded after the aging treatment at 423K
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effects of alloying copper and silicon on the bondability of dissimilar metal Joints of aluminum alloys to steel
Quarterly Journal of The Japan Welding Society, 2009Co-Authors: Y Saito, Hidetaka Umeshita, Tomo Ogura, Akio HiroseAbstract:The effects of Cu and Si in aluminum alloys on the Joint properties of Aluminum alloys/steels were evaluated by correlating the interfacial microstructures with the Joint Strength using diffusion bonding. It was found that Joint Strength was improved by adding Cu to aluminum alloys, because Cu suppressed formation and growth of a reaction layer. Moreover, the effect was much larger by Cu and Si combined addition. The fracture for the Joints with higher Strength occurred within the base aluminum alloys. As a reaction layer is thicker, the fracture mode was changed from an interfacial fracture to an aluminum alloy matrix and a reaction layer fracture, regardless of containing copper. For all investigated alloys, the highest Joint Strength was obtained in a certain value of reaction layer thickness, in particular, the optimum thickness value with the highest Joint Strength for Cu and Si combined alloy was smallest. By Cu and Si combined addition, our proposed guideline of the interfacial structure to obtain the Joints Strength more than 70 MPa was satisfied more easily. It was concluded that alloying of both Cu and Si to aluminum alloys improves the bondability of the Joints.
Thomas Keller - One of the best experts on this subject based on the ideXlab platform.
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ductile double lap Joints from brittle gfrp laminates and ductile adhesives part ii numerical investigation and Joint Strength prediction
Composites Part B-engineering, 2008Co-Authors: Julia Castro, Thomas KellerAbstract:Joint analysis using a non-linear finite element model has been performed to analyze the effects of adhesive ductility on the stiffness and Strength of full-scale adhesively-bonded double-lap Joints composed of brittle pultruded GFRP laminates. Experimental and numerical results of Joint and specimen elongations and axial strains in the bondline compared well. Calculated stress states at failure location inside the adherends showed that plastification of ductile adhesives provide uniform load transfer leading to increased Joint Strength. Joint Strength increases almost linearly with increasing overlap length. Flexible and stiff Joints are defined depending on the ratio of adhesive-to-adherend modulus. Flexible Joints exhibit lower stiffness than the adherends, while stiff Joints provide continuity of structural stiffness. The Strength of ductile adhesively-bonded Joints was predicted by extending an existing through-thickness shear-tensile-interaction failure criterion developed for brittle Joints with epoxy adhesive.
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adhesively bonded lap Joints from pultruded gfrp profiles part ii Joint Strength prediction
Composites Part B-engineering, 2005Co-Authors: Thomas Keller, Till ValleeAbstract:A method to predict the Strength of adhesively bonded single and double lap Joints from pultruded GFRP composite adherends subjected to quasi-static axial tensile loading is presented. The method is based on a quadratic through- thickness shear-tensile interaction failure criterion. The failure criterion was deduced from measured combined through-thickness tensile and shear Strength values in the outer fiber-mat layer of the adherends (locations of the ultimate failure). The experimental Strength values were obtained from a new shear-tensile interaction device (STI- device), which allows the measurement of shear-tensile interaction Strength values. The predicted Joint Strengths corresponded well to the measured Joint Strengths of adhesively bonded single and double lap Joints with different geometrical configurations. The investigation also showed that the material Strength depended on the expansion of the stressed surface. The resistance against local stress peaks was much higher than the resistance against large uniformly distributed stress blocks. The application of the ultimate failure load prediction method showed a small influence of the adhesive layer thickness on the Joint Strength although the influence of the fillet radius was seen to be much higher. A partial material safety factor for the Joint Strength of 1.34 was determined. [All rights reserved Elsevier]
Daejun Jung - One of the best experts on this subject based on the ideXlab platform.
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effect of surface pre oxidation on laser assisted joining of acrylonitrile butadiene styrene abs and zinc coated steel
Materials & Design, 2016Co-Authors: Daejun Jung, Jason Cheon, Suckjoo NaAbstract:Abstract Surface oxidation pre-treatment of zinc-coated steel was performed to verify its effect on enhancing the Joint Strength in the laser assisted joining of acrylonitrile butadiene styrene (ABS) and zinc-coated steel. Tensile shear tests indicated that the Joint Strength between pre-oxidized zinc-coated steel and ABS was considerably enhanced in comparison with that of untreated Joint. The zinc oxide layer was generated in the zinc layer by pre-treatment on zinc-coated steel and the thickness of the zinc oxide layer is proportional to the Joint Strength of joining as long as the Strength of zinc oxide layer is higher than that of the Jointed layer. When the thicker zinc oxide layer on the zinc-coated steel is reacted with carbon on the ABS, it increases the potential for chemical bonding between the zinc oxide and carbon (Zn O C). Using scanning electron microscopy (SEM) and coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) measurements, the strongly Jointed areas were evaluated at atomic or molecular levels to investigate the physical and chemical bonding between the reacted carbon layer and zinc oxide layer.
Yanbin Chen - One of the best experts on this subject based on the ideXlab platform.
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co2 laser welding brazing characteristics of dissimilar metals az31b mg alloy to zn coated dual phase steel with mg based filler
Journal of Materials Processing Technology, 2013Co-Authors: Liqun Li, Yanbin ChenAbstract:Abstract The influence of process variables including heating mode, flux, laser beam offset, and travel speed on the weld bead geometry and Joint Strength was investigated during laser welding–brazing (LWB) of AZ31B Mg alloy to Zn coated steel. The wettability of molten filler metal on steel surface was studied via a Charge-coupled Device (CCD) camera. The reaction layers along the interface were characterized and the failure mechanism was identified. Dual beam processing was found to preheat the steel substrate and promote the wettability of molten filler metal on the steel surface, thereby improving the corresponding Joint Strength. Utilizing a flux was found to produce a similar effect on molten filler metal. The optimized range of laser offset was found to be between 0.5 and 1.0 mm toward the steel side of the Joint. These optimized parameters led to a maximum Joint Strength of 228 N/mm. The Joint Strength was however found to decrease with increasing travel speed. Cracking was identified with travel speeds greater than 1 m/min. Microstructural characterization showed that heterogeneous interfacial reaction layers were produced from the seam head to the seam root of the Joint. The reaction layer thickness varied within a certain range when applying different process parameters, suggesting the growth of interfacial layer was not essentially related to the heat input. The primary failure mode of the lap specimens was interfacial fracture. Cracks propagated along the Mg–Zn reaction layer and steel interface. Original Fe–Al phase formed during the hot-dip galvanization process hindered the metallurgical bonding of Mg–Zn reaction layer and steel substrate, which was attributed to interfacial type failure.
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Joint Strength and failure mechanism of laser spot weld of mild steel sheets under lap shear loading
Science and Technology of Welding and Joining, 2008Co-Authors: Wang Tao, Yanbin ChenAbstract:AbstractUltimate Strength and failure mechanism of laser spot welds under lap shear loading were investigated. Optical micrographs of cross-section of spot welds before and after failure were examined to understand the failure behaviour. The experimental results indicate that laser spot welds can fail in two distinct modes, namely interfacial and pullout failure. A failure mechanism which was confirmed by SEM investigations was proposed to describe these two failure modes. According to the experimental observations, a simple stress solution related to the far field load was conducted and the critical weld nugget diameter to ensure pullout failure mode was estimated. The results were compared with the experimental data and also with the test data of resistance spot welds. It was observed that the critical nugget diameter of laser spot welding was larger than that of resistance spot welding due to the different failure location in pullout mode. Furthermore, the effect of welding parameters on Joint Strength...
Fengjiang Wang - One of the best experts on this subject based on the ideXlab platform.
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interfacial behavior and Joint Strength of sn bi solder with solid solution compositions
Journal of Materials Science: Materials in Electronics, 2018Co-Authors: Fengjiang Wang, Hong Chen, Ying HuangAbstract:To obtain the interfacial behaviors and the Joint Strength of Sn–Bi solid solution solder, Sn–2.5Bi and Sn–5Bi solders were selected to be investigated in this work with pure Sn/Cu solder Joints as a reference. The results showed that the growth behaviors of intermetallic compound (IMC) at Sn–Bi solder Joints were different under reflow soldering and isothermal aging, which was related with the presence of Bi atoms and the diffusion rate of Cu atoms. Furthermore, the Cu6Sn5 particles in solder matrix and the Bi precipitation could change the diffusion path of Cu atoms, which caused the change on the distribution and size of Cu6Sn5 in pure Sn, Sn–2.5Bi and Sn–5Bi solder matrix after isothermal aging. The size and distribution of Cu6Sn5 in solder matrix finally affected the shear Strength of solder Joints. The shear Strength of Sn–2.5Bi/Cu solder Joints increased compared with pure Sn/Cu solder Joints, and there was no obvious change with the aging times for Sn–2.5Bi/Cu solder Joints due to the effect of the reinforcement of Bi atoms. However, the shear Strength of Sn–5Bi/Cu solder Joints increased firstly and then decreased with the prolongation of aging times. This phenomenon was attributed to the segregation of Bi and the large amounts of Cu6Sn5 particles distributed in solder matrix during the aging condition. Besides, the IMC thickness in Sn–5Bi/Cu solder Joint played the important role on the shear Strength due to the brittle nature of IMC. In pure Sn solder matrix, the size of Cu6Sn5 particles were larger than that in Sn–Bi solder matrix, which deteriorated the shear Strength on pure Sn solder. From the observation on the fracture morphologies, Sn/Cu and Sn–2.5Bi/Cu solder Joints showed the ductile fracture occurred in the solder matrix, while Sn–5Bi/Cu solder Joints exhibited a mixed fracture.
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microstructural evolution and Joint Strength of sn 58bi cu Joints through minor zn alloying substrate during isothermal aging
Journal of Alloys and Compounds, 2016Co-Authors: Fengjiang Wang, Lili Zhou, Xiaojing WangAbstract:Abstract To improve the interfacial microstructure and mechanical behaviors of Sn-58Bi/Cu Joint, minor Zn element was alloyed into Cu substrate. The interfacial intermetallic compound (IMC) growth and bending properties of Sn-58Bi/Cu and Sn-58Bi/Cu-2.29Zn were studied with the effect of isothermal liquid and solid aging. Although there was no significant change on the composition, thickness and morphology of interfacial IMC under liquid aging, the depressing of IMC growth at the interface between Sn-58Bi solder and substrate and the avoidance on formation of Cu 3 Sn IMC, Kirkendall voids and Bi segregation at the IMC/Cu interface were realized with Cu-Zn substrate under isothermal solid aging. Joint Strength and fracture behavior were also improved by Cu-Zn substrate. There was no obvious decreasing on the Joint Strength and the fracture during bending was mainly occurred in the solder matrix with ductile fracture mode or along the solder/IMC interface with partly brittle fracture mode for Cu-Zn Joint compared with the dramatically decreasing on Joint Strength and brittle fracture mode occurred along the interface between IMC and Cu for Sn-Bi/Cu Joints after aging.
