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Kazuhiro Nakata - One of the best experts on this subject based on the ideXlab platform.
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Influence of probe offset distance on interfacial microstructure and mechanical properties of friction stir butt welded Joint of Ti6Al4V and A6061 dissimilar alloys
Materials & Design, 2014Co-Authors: Zhihua Song, Kazuhiro Nakata, Jinsun Liao, Aiping Wu, Li ZhouAbstract:Abstract Friction stir butt welding of titanium alloy Ti6Al4V and aluminum alloy A6061-T6 with 2 mm thickness was conducted by offsetting probe edge into the titanium alloy at rotation speed of 750 rpm and 1000 rpm and welding speed of 120 mm/min. The effect of probe offset distance on the interfacial microstructure and mechanical properties of the butt Joint was investigated. When the probe offset distance is not sufficient, the two alloys cannot be completely joined together, i.e. there exists no bonding or kissing bonding at the root part of Joint Interface. However, when the probe offset distance is too large, a great amount of intermetallic compounds are formed at the Joint Interface and its adjacency, leading to fracturing roughly along the Joint Interface during a tensile test. In a proper range of probe offset distance, sound dissimilar butt Joints are produced, which have comparatively high tensile strength and fracture in heat affected zone of the aluminum alloy during a tensile test.
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dissimilar metal joining of zk60 magnesium alloy and titanium by friction stir welding
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2012Co-Authors: Masayuki Aonuma, Kazuhiro NakataAbstract:Abstract Friction stir welding (FSW) is a solid-state joining process, and the joining temperature is lower than that in the fusion welding process. The effect of alloying elements on the microstructure of dissimilar Joints of a Mg–Zn–Zr alloy (ZK60) and titanium by using FSW, was examined. A commercial ZK60 and a titanium plates with 2 mm in thickness was butt-joined by inserting the probe into the ZK60 plate, and slightly offset into the titanium plate side to ensure the direct contact between them. The average tensile strength of the Joint was 237 MPa, which was about 69% of that of ZK60 and a fracture occurred mainly in the stir zone of ZK60 and partly at the Joint Interface. A thin Zn and Zr-rich layer with about 1 m in thickness was formed at the Joint Interface, which affected the tensile strength of the dissimilar Joint of ZK60 and titanium.
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microstructure at friction stir lap Joint Interface of pure titanium and steel
Materials Letters, 2010Co-Authors: Jinsun Liao, Naotsugu Yamamoto, Hong Liu, Kazuhiro NakataAbstract:Abstract A commercially pure titanium plate was lap joined to a structural steel plate via friction stir welding, and the microstructures at the lap Joint Interface were intensively examined by means of electron backscatter diffraction analysis and transmission electron microscopy. Swirling-like macro- and micro-intermixing zones of titanium and steel are formed along the Interface, where tiny Fe–Ti intermetallic particles are dispersed and mixed with β titanium in layers. The lap Joint has high shear tensile strength, which is supposed to result from the dispersion of tiny Fe–Ti intermetallic particles and the formation of β titanium at the Joint Interface.
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effect of calcium on intermetallic compound layer at Interface of calcium added magnesium aluminum alloy and titanium Joint by friction stir welding
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2010Co-Authors: Masayuki Aonuma, Kazuhiro NakataAbstract:Abstract Commercial AMCa602 alloy (Mg–6% Al–2% Ca) and AM60 alloy (Mg–6% Al) were joined to titanium plates by friction stir welding to evaluate the effect of a calcium on the reaction layer at the dissimilar Joint Interface and the Joint tensile strength. At the titanium and AM60 Joint Interface, a TiAl3 intermetallic compound layer was formed. The thickness of this layer was about 2 μm. A layer containing calcium and a layer containing aluminum and titanium were observed at the titanium and AMCa602 Joint Interface. The aluminum and titanium layer in the titanium and AMCa602 Joint Interface was very thin. The content of aluminum in solid-solution in the matrix of AMCa602 was lower than that of AM60 due to the formation of a Ca–Al compound, and this suppressed the formation of TiAl3 at the titanium and AMCa602 Joint Interface.
Fusahito Yoshida - One of the best experts on this subject based on the ideXlab platform.
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development of cu sn intermetallic compound at pb free solder cu Joint Interface
Materials Letters, 2003Co-Authors: Fengjiang Wang, Yiyu Qian, Fusahito YoshidaAbstract:Abstract The development of Cu–Sn intermetallic compound (IMC) at the solder/Cu Joint Interface had been studied using two Pb-free solders, Sn–3.8Ag–0.7Cu and Sn–2Ag–0.8Cu–0.6Sb alloys. Meanwhile, 100Sn/Cu Joint was applied for comparison. Both Pb-free solder Joints were found with thinner Cu–Sn IMC layers at as-soldered state due to the slower dissolution rate of intermetallic compound into the liquid Pb-free solders during reflow and, consequently, slower growth rates of Cu–Sn IMC during the solid-state thermal aging at 125 °C, where Sn–2Ag–0.8Cu–0.6Sb solder Joint gave the minimum value. Thermodynamic analysis showed that such phenomena could be attributed to the reduction of the driving force for Cu–Sn IMC formation due to the existence of Ag and Sb atoms.
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Development of Cu-Sn intermetallic compound at Pb-free solder/Cu Joint Interface
Materials Letters, 2003Co-Authors: Fengjiang Wang, Yiyu Qian, Fusahito YoshidaAbstract:Abstract The development of Cu–Sn intermetallic compound (IMC) at the solder/Cu Joint Interface had been studied using two Pb-free solders, Sn–3.8Ag–0.7Cu and Sn–2Ag–0.8Cu–0.6Sb alloys. Meanwhile, 100Sn/Cu Joint was applied for comparison. Both Pb-free solder Joints were found with thinner Cu–Sn IMC layers at as-soldered state due to the slower dissolution rate of intermetallic compound into the liquid Pb-free solders during reflow and, consequently, slower growth rates of Cu–Sn IMC during the solid-state thermal aging at 125 °C, where Sn–2Ag–0.8Cu–0.6Sb solder Joint gave the minimum value. Thermodynamic analysis showed that such phenomena could be attributed to the reduction of the driving force for Cu–Sn IMC formation due to the existence of Ag and Sb atoms.
H Ahmadian - One of the best experts on this subject based on the ideXlab platform.
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modelling machine tool dynamics using a distributed parameter tool holder Joint Interface
International Journal of Machine Tools & Manufacture, 2007Co-Authors: Keivan Ahmadi, H AhmadianAbstract:Abstract Increasing productivity in machining process demands high material removal rate in stable cutting conditions and depends strongly on dynamic properties of machine tool structure. Combined analytical–experimental procedures based on receptance coupling substructure analysis (RCSA) are employed to determine the stability of machine operating conditions at different tool configurations. The RCSA employs holder–spindle experimental mobility measurements in conjunction with an analytical model for the tool to predict the dynamics of different sets of tool and holder–spindle combinations without the need for repeated mobility measurements. In this paper an alternative approach using the concept of tool on resilient support is adopted to predict the machine tool dynamics in various tool configurations. In the proposed model the tool, represented by an analytical model, is partly resting on a resilient support provided by the holder–spindle assembly. The support dynamic flexibility is measured by performing vibration tests on the holder–spindle assembly. Tool–holder Joint Interface characteristics are included in the model by considering a distributed elastic Interface layer between the holder–spindle and the tool shank part. The distributed Interface layer takes into account the change in normal contact pressure along the Joint Interface and comparing with the lumped Joint model used in RCSA it allows more detailed representation of the Joint Interface flexibility and damping which have crucial roles in machine dynamics. Experiments are conducted to demonstrate the efficiency of proposed model in prediction of milling operation dynamics and it is shown that the model is capable of accurately predicting the dynamic absorber effect of spindle in a tool tuning practice.
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generic element formulation for modelling bolted lap Joints
Mechanical Systems and Signal Processing, 2007Co-Authors: H Ahmadian, Hassan JalaliAbstract:Joints have significant effects on the dynamic response of the assembled structures due to existence of two non-linear mechanisms in their Interface, namely slipping and slapping. These mechanisms affect the structural response by adding considerable damping into the structure and lowering the natural frequencies due to the stiffness softening. Neglecting these effects in modelling of Joints produces errors in predictions of the structure responses. In this paper, a non-linear generic element formulation is developed for modelling bolted lap Joints. The generic element is formed by satisfying all conditions that are known for a Joint Interface and hence providing a non-linear parametric formulation for the families of allowable Joint models. Dynamic response of the developed model for the assembled structure including the generic Joint Interface element is obtained using the incremental harmonic balance (IHB) method. The generic parameters of the Joint are identified by minimising the difference between the model response obtained from IHB method and the observed behaviour of the structure. The procedure is demonstrated by modelling an actual structure containing a single lap bolted Joint in the middle. The frequency responses of the structure around the first two resonance frequencies are measured by exciting the structure using a sinusoidal force at each individual frequency. The measured responses are compared with the predictions of the model containing a parametric generic Joint element. The parameters of the Joint Interface model are successfully identified by minimising the difference between the measured responses and the model predictions.
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identification of bolted lap Joints parameters in assembled structures
Mechanical Systems and Signal Processing, 2007Co-Authors: H Ahmadian, Hassan JalaliAbstract:Bolted lap Joints have significant influence on the dynamical behaviour of the assembled structures due to creation of strong local flexibility and damping. In modelling the dynamical behaviour of assembled structures the Joint Interface model must be represented accurately. A nonlinear model for bolted lap Joints and Interfaces is proposed capable of representing the dominant physics involved in the Joint such as micro/macro-slip. The Joint Interface is modelled using a combination of linear and nonlinear springs and a damper to simulate the damping effects of the Joint. An estimate of the response of the structure with a nonlinear model for the bolted Joint under external excitations is obtained using the method of multiple scales. The parameters of the model, i.e. the spring constants and the damper coefficient, are functions of normal and tangential stresses at the Joint Interface and are identified by minimizing the difference between the model predictions and the experimentally measured data.
Fengjiang Wang - One of the best experts on this subject based on the ideXlab platform.
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development of cu sn intermetallic compound at pb free solder cu Joint Interface
Materials Letters, 2003Co-Authors: Fengjiang Wang, Yiyu Qian, Fusahito YoshidaAbstract:Abstract The development of Cu–Sn intermetallic compound (IMC) at the solder/Cu Joint Interface had been studied using two Pb-free solders, Sn–3.8Ag–0.7Cu and Sn–2Ag–0.8Cu–0.6Sb alloys. Meanwhile, 100Sn/Cu Joint was applied for comparison. Both Pb-free solder Joints were found with thinner Cu–Sn IMC layers at as-soldered state due to the slower dissolution rate of intermetallic compound into the liquid Pb-free solders during reflow and, consequently, slower growth rates of Cu–Sn IMC during the solid-state thermal aging at 125 °C, where Sn–2Ag–0.8Cu–0.6Sb solder Joint gave the minimum value. Thermodynamic analysis showed that such phenomena could be attributed to the reduction of the driving force for Cu–Sn IMC formation due to the existence of Ag and Sb atoms.
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Development of Cu-Sn intermetallic compound at Pb-free solder/Cu Joint Interface
Materials Letters, 2003Co-Authors: Fengjiang Wang, Yiyu Qian, Fusahito YoshidaAbstract:Abstract The development of Cu–Sn intermetallic compound (IMC) at the solder/Cu Joint Interface had been studied using two Pb-free solders, Sn–3.8Ag–0.7Cu and Sn–2Ag–0.8Cu–0.6Sb alloys. Meanwhile, 100Sn/Cu Joint was applied for comparison. Both Pb-free solder Joints were found with thinner Cu–Sn IMC layers at as-soldered state due to the slower dissolution rate of intermetallic compound into the liquid Pb-free solders during reflow and, consequently, slower growth rates of Cu–Sn IMC during the solid-state thermal aging at 125 °C, where Sn–2Ag–0.8Cu–0.6Sb solder Joint gave the minimum value. Thermodynamic analysis showed that such phenomena could be attributed to the reduction of the driving force for Cu–Sn IMC formation due to the existence of Ag and Sb atoms.
Keivan Ahmadi - One of the best experts on this subject based on the ideXlab platform.
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modelling machine tool dynamics using a distributed parameter tool holder Joint Interface
International Journal of Machine Tools & Manufacture, 2007Co-Authors: Keivan Ahmadi, H AhmadianAbstract:Abstract Increasing productivity in machining process demands high material removal rate in stable cutting conditions and depends strongly on dynamic properties of machine tool structure. Combined analytical–experimental procedures based on receptance coupling substructure analysis (RCSA) are employed to determine the stability of machine operating conditions at different tool configurations. The RCSA employs holder–spindle experimental mobility measurements in conjunction with an analytical model for the tool to predict the dynamics of different sets of tool and holder–spindle combinations without the need for repeated mobility measurements. In this paper an alternative approach using the concept of tool on resilient support is adopted to predict the machine tool dynamics in various tool configurations. In the proposed model the tool, represented by an analytical model, is partly resting on a resilient support provided by the holder–spindle assembly. The support dynamic flexibility is measured by performing vibration tests on the holder–spindle assembly. Tool–holder Joint Interface characteristics are included in the model by considering a distributed elastic Interface layer between the holder–spindle and the tool shank part. The distributed Interface layer takes into account the change in normal contact pressure along the Joint Interface and comparing with the lumped Joint model used in RCSA it allows more detailed representation of the Joint Interface flexibility and damping which have crucial roles in machine dynamics. Experiments are conducted to demonstrate the efficiency of proposed model in prediction of milling operation dynamics and it is shown that the model is capable of accurately predicting the dynamic absorber effect of spindle in a tool tuning practice.
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Modelling machine tool dynamics using a distributed parameter tool–holder Joint Interface
International Journal of Machine Tools & Manufacture, 2007Co-Authors: Keivan Ahmadi, Hamid AhmadianAbstract:Abstract Increasing productivity in machining process demands high material removal rate in stable cutting conditions and depends strongly on dynamic properties of machine tool structure. Combined analytical–experimental procedures based on receptance coupling substructure analysis (RCSA) are employed to determine the stability of machine operating conditions at different tool configurations. The RCSA employs holder–spindle experimental mobility measurements in conjunction with an analytical model for the tool to predict the dynamics of different sets of tool and holder–spindle combinations without the need for repeated mobility measurements. In this paper an alternative approach using the concept of tool on resilient support is adopted to predict the machine tool dynamics in various tool configurations. In the proposed model the tool, represented by an analytical model, is partly resting on a resilient support provided by the holder–spindle assembly. The support dynamic flexibility is measured by performing vibration tests on the holder–spindle assembly. Tool–holder Joint Interface characteristics are included in the model by considering a distributed elastic Interface layer between the holder–spindle and the tool shank part. The distributed Interface layer takes into account the change in normal contact pressure along the Joint Interface and comparing with the lumped Joint model used in RCSA it allows more detailed representation of the Joint Interface flexibility and damping which have crucial roles in machine dynamics. Experiments are conducted to demonstrate the efficiency of proposed model in prediction of milling operation dynamics and it is shown that the model is capable of accurately predicting the dynamic absorber effect of spindle in a tool tuning practice.
