bluuebunny/crossref_metadata_2025 huggingface dataset:
Cross-Ply Laminates under Static Three-Point Bending: A Numerical Development Model
Authors: Benbelaid S. , Bezzazi B. , Bezazi A.
Published: January 2012

This paper considers damage development mechanisms in cross-ply laminates using an accurate numerical model. Under static three points bending, two modes of damage progression in cross-ply laminates are predominated: transverse cracking and delamination. However, this second mode of damage is not accounted in our numerical model. After a general review of experimental approaches of observed behavior of laminates, the focus is laid on predicting laminate behavior based on continuum damage mechanics. In this study, a continuum damage model based on ply failure criteria is presented, which is initially proposed by Ladevèze. To reveal the effect of different stacking sequence of the laminate; such as thickness and the interior or exterior disposition of the 0° and 90° oriented layers in the laminate, an equivalent damage accumulation which cover all ply failure mechanisms has been predicted. However, the solution algorithm using finite element analysis which implements progressive failure analysis is summarized. The results of the numerical computation have been justified by the previous published experimental observations of the authors.
Investigation on the Chemical Mechanical Polish of Metal Os
Authors: Chu Xiang Feng , Tang L.J. , Dong Y.P. , Qiao H.B. , Bai L.S.
Published: January 2012

Osmium (Os) may be used as new barrier material in copper interconnects of ultra-large scale integration. In this work, chemical mechanical polish experiments were done on Os disk using home-made slurry, the effect of pH value, down force, chelating agents, inhibitor species, the concentration of the inhibitor, H2O2 concentration and SiO2 concentration on material removal rate (MRR) was investigated. The results reveal that MRR is 13.1 nm/min when the slurry contains 1wt.% H2O2, 1wt.% SiO2, 1 wt.% citric acid, 1mM BTA and pH =9 and the down force was 1 psi. The influence of the BTA concentration on the corrosion on the surface of Os was analyzed using electrochemical analysis method; it was found that the maximum value of Ecorr appeared when the BTA concentration was 1.5 mm
Optimal Design of a New Type of Savonius Rotor Using Simulation Analysis
Authors: Tang Zhi Peng , Yao Ying Xue , Zhou Liang , Yao Q.
Published: January 2012

In order to enhance the efficiency of the Savonius rotor, this paper designs a new type of Savonius rotor with a rectifier. By using Computational Fluid Dynamics software to simulate and optimize the various parameters which affect the efficiency of the rotor. The sliding mesh method is applied here. The Cp-λ curves of wind turbine with different structural parameters are obtained after numerical simulation of flow field. On this basis, this paper gets the optimal structural parameters. And the results indicated that this new type of Savonius rotor has great improvement of efficiency compared with the traditional Savonius-type rotor.
Optimization of Diamond-Coated Drawing Dies for Low Carbon Steel Tubes Based on the FEM Simulation
Authors: Lin Zi Chao , Shen Bin , Sun Fang Hong , Zhang Z.M. , Shen H.S. , Guo S.S.
Published: January 2012

Diamond-coated drawing dies are considered as ideal drawing dies for their unique characteristics, such as high hardness, wear resistance and low friction. In order to utilize the superior characteristics of diamond coatings towards improving the drawing performance, the nonlinear FEM simulation is used to simulate the whole low carbon steel tube hollow sinking process, with 2D axi-symmetric elastic-plastic element. Based on the simulation results, the distributions of the axial stress and radial stress are analyzed, the influence of parameters of drawing dies on the diameter shrinkage is investigated. Optimal die parameters are obtained.
Progressive Tool Wear in Diamond Cutting of Glass Soda-Lime
Authors: Jia Peng , Zhou M. , Huang S.N.
Published: January 2012

For the technology of diamond cutting of optical glass, the high tool wear rate is a main reason for hindering the practical application of this technology. Minimizing the tool wear is of great significance in order to achieve the satisfactory surface quality and dimensional accuracy. For in depth understanding of the tool wear mechanisms, experiments of diamond turning with cutting distance increased gradually was carried out on soda-lime glass in this work. Experimental results indicate that the flank wear was predominant in diamond cutting glass and the flank wear land was characterized by micro-grooves, some smooth crater on the rake face was also seen. The mainly mechanisms inducing tool wear in diamond cutting of glass are diffusion, mechanical friction, thermo-chemical action and abrasive wear.
Analysis and Prediction Approach to the Thin-Walled Workpiece Deformation with Thermo-Mechanical Couple Consideration
Authors: Zhong Xiao Hong , Qin Guo Hua , Sun S.P. , Lu D.
Published: January 2012

The metal cutting is a complexly dynamic physical process of thermal-mechanical coupling. It is difficult in analyzing the mechanism of machining deformation with the traditional calculation method. The key simulation technologies of the machining process are analyzed by means of finite element method (FEM), such as material constitutive model, chip separation criterion, tool-chip interaction and friction model, thermal control equation. During finite element simulation of the peripheral milling of the thin-walled workpiece, the contact constraints between the tool and workpiece can be effectively simplified. Thus, the tool and workpiece are considered as rigid and elastic bodies, respectively. In sequence, the unit birth and death technology is used to simulate the material removal in the milling process so that the effect of the workpiece size on machining deformation can be researched accurately. The investigation on the theory and application of the above key technologies can not only analyze and predict the deformation of thin-walled parts, but also optimize process parameters to control the machining deformation.
Simulation of Fabrication for Single-Phase Al2O3 Ceramic Tool Materials at Different Fabrication Pressure
Authors: Fang Bin , Huang Chuan Zhen , Xu Chong Hai , Sun Sheng
Published: January 2012

The relationship between fabrication pressure and microstructure evolution is proposed. A computer simulation coupled with fabrication pressure for the hot-pressing process of single-phase ceramic tool materials has been developed, which uses a two-dimensional hexagon lattice model mapped from the realistic microstructure without considering the presence of pores. The fabrication of single-phase Al2O3 is simulated. The mean grain size of simulated microstructure by Monte Carlo Potts model integrated with fabrication pressure increases with an increase in fabrication pressure, which is consistent with the experiment results. It is shown that Monte Carlo Potts model coupled with fabrication pressure may simulate the microstructure evolution of single-phase ceramic tool materials.
Simulation on Heat Exchange Performance of Heat Pipe Grinding Wheel
Authors: He Q.S. , Fu Y.C. , Xu Jiu Hua , Zhang B.F.
Published: January 2012

A three dimension heat transfer model, using a commercial code Fluent software which was based on FEM, was developed to describe the grinding process of heat pipe grinding wheel in this paper. Temperature field of heat pipe grinding wheel was analyzed by this model to identify the effects of different conditions on the temperature of the work surface of grinding wheel including the heat flux of contact zone, cooling parameter and rotation speed of grinding wheel. The heat exchange performance of heat pipe grinding wheel also was studied based on the temperature of the work surface of grinding wheel. Model calculations showed that the high heat flux and unsatisfactory cooling capacity could cause a high temperature of the work surface of grinding wheel as well as the temperature of the work surface of grinding wheel was not affected by the rotation speed of grinding wheel. A significant amount of the input heat could be taken away from the heat pipe grinding wheel.
Charged Uniform Molten Metal Droplet Spray as a Rapid Prototyping Technology
Authors: Gao Sheng Dong , Lu Yong , Yao Ying Xue
Published: January 2012

Uniform molten metal droplet stream from jet break-up provides potential technology for metal parts rapid prototype manufacturing. In this study an experimental device capable of producing uniform metal droplet stream has been developed. Monosize spherical powders of 180m in diameter can be obtained after cooling and solidification. Then the droplets were electrostatically charged and deflected during flight to deposit onto a revolving substrate to form a 3D metal part.
Analysis of Structural Parameters of Grooved-Wicksin Micro Heat Pipes Based on Capillary Limits
Authors: Li Xi Bing , Shi Z.M. , Wang S.G. , Hu Q.M. , Bao L. , Zhang H.J.
Published: January 2012

For great progress in heat pipe technology, a micro heat pipe has become an ideal heat dissipating device in high heat-flux electronic products, and capillary limit is the main factor affecting its heat transfer performance. Based on analyses of capillary limit and currently commonly-used groove structures, this paper built capillary limit models for micro heat pipes with dovetail-groove, rectangular-groove, trapezoidal-groove and V-groove wick structures respectively for theoretical analyses. The analysis results show that better heat transfer performances can be obtained in micro heat pipes with small-angle dovetail (i.e. a sector structure), rectangular and small-angle trapezoidal grooved wick structures when groove depth is 0.2-0.3mm and top-width-to-depth ratio is 1.2-1.5.
Effect of Cutter Rake Angle on Cutter V-Tip Wear and Micro-Groove Quality in Micron-Scale Turning of Steel
Authors: He X.L. , Xie Jin , Xie H.F. , He J.L.
Published: January 2012

In mechanical micro-grooving, cutter V-tip shape and wear greatly influence the generation of micro-groove on workpiece surface. Hence, cutter V-tip wear and micro-groove shape were observed in micro-grooving experiments. The objective is to understand the generation mechanism of micro-grooves. First, the high-speed steel cutter was ground to be a V-tip whose tip radius is 5 m; then a turning experiment was performed to pattern the micro-grooves on steel surface using the cutter V-tip; then the cutter tip wear and the machined micro-groove shape were measured and evaluated; finally, the effect of cutter rake angle was investigated on cutter tip wear and micro-groove quality. It is shown that the machined groove tip radius is much larger than the sharpened cutter tip radius due to the rapid cutter tip wear during grooving. On increasing cutter rake angle, the cutter V-tip wear decreases, thus leading to the improvement of form accuracy and surface roughness of machined micro-grooves are both improved.
Fabrication of Composite Blocks Containing Alumina Bubble Particles for Porous CBN Abrasive Wheels
Authors: Pan Q. , Ding Wen Feng , Xu Jiu Hua , Zhang B. , Su H.H. , Fu Y.C.
Published: January 2012

Alumina (Al2O3) bubble particles were added into the mixture of CBN abrasive grains, Cu-Sn-Ti alloy and graphite particles to prepare the composite blocks for porous CBN abrasive wheels. The specimens were sintered at the temperature of 920°C for the dwell time of 30 min. The bending strength of the composite blocks was measured by the three-point bending tests. The fracture surface of the blocks was characterized. The results show that, the content of alumina bubble particles does not take significant effect on the mechanical strength of the composite blocks. Even the lowest strength of the composite blocks, 98 MPa, is higher than that of the vitrified CBN abra-sive wheels. Cu-Sn-Ti alloy has bonded firmly alumina particles and CBN grains by means of the chemical reaction and corresponding products. Finally, the chip space was formed through the re-moval of the ceramic wall of the alumina bubble particles within the CBN abrasive wheel during dressing.
Mechanical Modeling of Plowing Process and Experimental Validation
Authors: Jiang Feng , Yan L. , Rong Y.M. , Liu Y.P.
Published: January 2012

In this study, mechanical model of plowing process considering material flow process was built. Dynamic material model of workpiece (AISI D2) was included in this plowing model. The friction between diamond indenter against AISI D2 steel was obtained by the ball-on-plate test. The scratch tests with diamond indenter against AISI D2 steel were performed. The scratch morphology was investigated by white light interferometer. The scratch forces in the different loads were calculated by the mechanical model of plowing process. The calculated scratch forces showed good agreement with experimental results.
Modeling and Identification of High Speed High Accuracy Lightweight Stages with Flexible Arms
Authors: Fan S.X. , Fan D.P. , Zhang Z.Y. , Lu Y.F.
Published: January 2012

Light-weight structures operating at high speeds may suffer from significant vibration problems, thus degrading positioning accuracy and exhibiting large settling time. High-performance vibration and motion controllers are usually designed based on precise dynamic model. This paper addresses the problem of modeling and identification of a high speed high accuracy lightweight positioning stage with flexible arm. A simplified state space model for vibration motion control purpose is given. A separated identification method is proposed. The parameters related to rigid body part and flexible body part are identified, separately. Rigid body dynamics is firstly identified by employing unbiased Least Squares technique. Subsequently, flexible body dynamics is identified by impact test and nonlinear LS technique. The experiment results show that applying proposed identification strategy can get more precise low frequency rigid body dynamic parameters without loss the identification precision of high frequency parameters.
Modeling and Simulation of Grain Growth of Ceramic Material in Sintering Process
Authors: Wang Min , Ai Xing , Zhao Jun , Zhou Yong Hui
Published: January 2012

The grain growth in the sintering process of ceramic materials has an important impact on the ceramic materials performance. In this paper, a grain growth simulation model considering the requirement of heat and space is established. The Al2O3-based ceramic materials are preparation, and the model is verified by the Al2O3-based ceramic materials. The simulated results of the grain growth by the model are very close to the grain growth of Al2O3-based ceramic materials. The model can be used in the study of grain growth in ceramic materials sintering process.
Numerical Study of Pitch Angle on H-Type Vertical Axis Wind Turbine
Authors: Yao Qi , Yao Ying Xue , Zhou Liang , Zheng S.Y.
Published: January 2012

This paper presents a simulation study of an H-type vertical axis wind turbine. Two dimensional CFD model using sliding mesh technique was generated to help understand aerodynamics performance of this wind turbine. The effect of the pith angle on H-type vertical axis wind turbine was studied based on the computational model. As a result, this wind turbine could get the maximum power coefficient when pitch angle adjusted to a suited angle, furthermore, the effects of pitch angle and azimuth angle on single blade were investigated. The results will provide theoretical supports on study of variable pitch of wind turbine.
Postprocessor of 5-Axis Non-Orthogonal Machining Center
Authors: Wu H.B. , Liu Y.W. , Zuo D.W.
Published: January 2012

The 5-aix machining postprocessor of non-orthogonal machine tool is difficult to develop. On the analysis of characteristics of non-orthogonal machining center with dual worktables and 5-axis milling programming, a postprocessing algorithm of 5-axis milling is presented. Based on the algorithm, a postprocessor is developed by Visual C++ to convert tool path file to G-code file. For tentative validation of the postprocessor, a simulation model of the machine is established by Ver-icut to simulate G-code files created by the program. Finally a test workpiece is machined, which confirms the validity of the postprocessor.
Analysis on Milling Deformation of 7022 Aluminum Alloy Blank Jointed by FSJ
Authors: Zuo Dun Wen , Wang Hong Feng , Miao Hong , Wang H.J.
Published: January 2012

Milling process of jointing blank of 7022 aluminum alloy was simulated by ANSYS. The results show that the maximum residual tensile stress and pressure stress are mainly concentrated in the jointing seam zone when the jointing blank is milled. The milling deformation of jointing blank is shown as “wave” shape. The milling deformation of key eye side is shown upwarp. The jointing initiating terminal is shown downward displacement. The maximum downward displacement is present to the middle of jointing seam central line. In additional, the milling deformation along sheet length direction is shown outward extension.
Research on Dynamic Behavior of Disc Indexing Cam Mechanism Based on Virtual Prototype Technology
Authors: Zhao Hao Dong , Guo Pei Quan , Cao Y.K. , Wang X.W. , Zhang P.
Published: January 2012

Dynamic modelling method for disc indexing cam mechanism was presented based on virtual prototype technology according to the analysis of mechanism feature. Rigid-flexible coupled dynamic model was established by means of Adams, Pro/E and Ansys softwares. Dynamic simulation has been done. It follows the analysis of simulation that effects of input speed, and stroke angle to torsional vibration were illustrated corresponding to dynamics simulation. Dynamic characteristics of different transmission functions commonly used in practical engineering were analyzed in detail. The application principle of transmission functions was presented based on dynamic simulation and analysis results. Construction method of transmission function was presented finally.
Research on the Constant Removal Rate of Coordinate Finishing Crankshaft Crankpin with Abrasive Tap
Authors: Zhang Mei , Huang Yun , Zhang L.
Published: January 2012

Coordinate polishing technology with abrasive tap is targeted for crankshaft, camshaft, eccentric shaft and other complex surface polishing. In the process of coordinate polishing crankshaft crankpin with abrasive tap, the constant removal rate is to ensure accuracy rate of removal, which is very important factor. This article is to mainly analyze constant rate of removal. First, analyzing the movement model of a single abrasive and on the exact model and the constant speed along under the conditions of uniform rotation of the crankshaft still grinding the neck of a diagram analysis, we found that controlling the abrasive in constant linear speed and constant pressure under the crankpin can achieve constant rate of removal. Then, when the abrasive is moving with constant speed under the crankpin, we analyses on the laws of crankshaft rotation and institutions movement, and simulates the equation of motion, Those curves are no mutations and to meet the engineering requirements. Finally, in order to ensure coordinate polishing crankshaft crankpin with abrasive tap with the polishing block clamping force, that is constant pressure grounding, so coordinate institutions must be analyzed counter weight. Those curves are no mutations and to meet the engineering requirements.
Simulation on Grind-Hardening Residual Stress Field of 48MnV Steel
Authors: Li Shu Sheng , Xiao Bing , Su H.H. , Gong S.L.
Published: January 2012

By using ANSYS, the temperature distribution in workpiece of steel 48MnV under the actions of a moving thermal source, is first carried out by FEM for non-linear transient temperature field. On this basis, the residual stress distribution in the workpiece under the action of temperature variation and moving grinding loads is determined by FEM for thermo elastic-plasticity. The result shows that the existent residual stress on surface of grinding hardening is press. The reason of this is discussed. The difference between the simulated value and measured value of grind-hardening stress is acceptable.
Study of Cutting Forces Models for Micro-Cutting Based on Strain Gradient
Authors: Wu Wen Ge , Xiao H. , Wang H.F. , Xiao T.
Published: January 2012

In micro-cutting process, it is very significant to study the variations of cutting forces and the factors affecting the forces for determining the machining parameters and for improving the performance of machining systems. The remarkable characteristic of micro-Cutting is that cutting parameters level closing to the crystal grain msize of material. Though, the prediction formula of micro-cutting forces should reference to strain gradient plasticity theory in formula construction, while cutting edge radius had been regard as a important parameters in the process of micro-cutting. The study show that, strain gradient reaction will be decreased by feed rate’s reducing in process, approximate expression of the strain gradient by the derivative of chip deformation rate, and the micro-cutting forces include hear flow stress, tensile flow stress ,and the friction force of rake surface.
Study on Macro-Morphology of Hard Whirling Chips
Authors: Zhu Hong Yu , Li Ying
Published: January 2012

The technology of hard whirling is a kind of advanced manufacturing technology which integrates high efficiency, high precision and energy saving as a whole and attracts wide attention in machining field around home and abroad. Through studying on experiment of hard whirling machining on rolling bearing steel which has average hardness at 63.5HRC, this article focuses on different understanding of saw-tooth chips, illustrates the essential difference between macro- morphology and micro-morphology of saw-tooth chips, analyzes macro- morphology of saw-tooth chips with their corresponding machining parameters and finally raises a new solution to implement online monitoring on hard whirling machining.
Study on Tool Wear and Cutting Torque of Gun Drill
Authors: Wang Yong Guo , Yan Xiang Ping , Tu G.C.
Published: January 2012

The force model of gun drill was put forward. It was found that the torque was sensitive to wear and carried the information of the status of wear stage. Moreover, friction between wear pad and work piece was the main source of torque. The experiment applied in studying the correlation between torque and wear has been performed on gun drill with and without TiAlN coating for machining steel S48CSiV with minimum quantity lubrication (MQL). The torque was increasing responding to the increasing wear of gun drill. The TiAlN coating delayed the wear rate and decreased the torque in the initial wear and gradual wear stage of the coated gun drill. The spallation of coating always led to the premature failure of coated gun drill and the spallation appeared if the rubbing and sliding force generated in the interface between the wear pad and the newly surface of work piece after drilling obtained a higher value than the coating’s adhered strength to carbide substrate materials.
Chemical Mechanical Polish of Potential New Barrier Material Ruthenium (Ru) in ULSI Copper Interconnects
Authors: Chu Xiang Feng , Li X.J. , Dong Y.P. , Qiao H.B. , Bai L.S.
Published: January 2012

Ruthenium (Ru) and ruthernium alloys may be utilized as new copper barrier materials in copper interconnects of ultra-large scale integration (ULSI), and chemical mechanical polish (CMP) can be applied in planarization for ULSI production. In this paper, CMP experiments were done on high purity Ru by using home-made slurry, the effect of oxidizer, complexing agent, polishing downforce, pH value, inhibitor species and inhibitor concentration on the material removal rate (MRR) was investigated. The results revealed that MRR can reach 8.7 nm/min under the following conditions: the main constituents in slurry were 1 wt.% SiO2, 1 wt.% (NH4)2S2O8, 1 wt.% tartaric acid and 3 mM imidazole, the pH value was 8.0, the down force was 2.5 psi (17.24 kPa); the roughness Ra was 7.6 nm under these conditions.
The Development of the Efficiency Enhancement Mechanism of the Vertical Axis Wind Turbine
Authors: Yao Qi , Yao Ying Xue , Zhou Liang , Tang Zhi Peng
Published: January 2012

The energy issue has been the focus of world’s attention. Wind plays a crucial role in the development and application of new energy as a renewable and clean energy. Wind turbine is the core component of the wind power system. It usually can be divided into horizontal axis wind turbine (HAWT) and vertical axis wind turbine (VAWT) by the relative position of the spindle and the ground. This paper analyzes the advantages and disadvantages of VAWT and summarizes the improvement of the VAWT from the energy congregating technology and self-starting technology which can provide technical support for the research of VAWT in the future.
Tool Wear Monitoring Based on Milling Acoustic Spectrum LPCC
Authors: Ai Chang Sheng , Sun Y.J. , He G.W.
Published: January 2012

Cutting sound signal are acquisited in the vertical machining center using electret microphone, and would be applied to monitor tool wear. Linear Predictive Cepstrum Coefficient (LPCC) of milling sound signal within audibility threshold would be extracted as acoustic spectrum characteristic parameters, and the relativity between LPCC each order component and tools radial wear was analyzed. The experiments and analysis results conclude that there are characteristic components associated with tool wear in characteristic parameters LPCC of milling sound signal; the characteristic components associated with tool wear are mainly concentrated in the 6th, 7th and 8th order components LPCC; the method by characteristic parameters LPCC monitoring tool wear is feasible.
Application of a Fuzzy EOQ Model to the Stock Management in the Manufacture System
Authors: Chou Chien Chang , Yih J.M. , Ding J.F. , Han T.C. , Lin Y.H. , Liu L.J. , Hsu W.K.
Published: January 2012

In a manufacture system, the inventory control is one of important issues. This paper proposes a fuzzy economic order quantity (EOQ) inventory model for solving the inventory control problem in the manufacture system. Firstly, this paper discusses the square roots of a trapezoidal fuzzy number. Secondly, the square root of fuzzy number is applied to the EOQ inventory model in the manufacture system.
Influence of Bond Material Concentration on the Mechanical Properties of Fixed Abrasive Lapping Tool for Stainless Steel
Authors: Zhu C.R. , Lv B.H. , Yuan Ju Long
Published: January 2012

To improve the machining efficiency as well as surface roughness, a resin-bonded fixed abrasive tool is developed for lapping process of stainless steel substrate. To optimize the lapping ability of the fixed abrasive tool, the influences of bond material concentration on the mechanical properties of fixed abrasive lapping tool, including structure hardness, shear strength, the water-absorbing capacity and modulus of elasticity in compression are investigated. The micro structure of tools is also observed. Tools made of #1000 SiC abrasive and resin with different concentrations is employed in the tests. It is found, the hardness, shear strength, and modulus of elasticity in compression reach highest value, as the 35%wt bond material are used. The water-absorbing capacity increases as the bond material concentration decreases. It is judged from the SEM images that the number of pores in tool with 35%wt bond material is at the most.
Research on Lean Assembly
Authors: Liu Y.H. , Zuo Dun Wen
Published: January 2012

Lean Production, which was born in manufacturing industry, is considered to be the most suitable production mode for the modern manufacturing enterprises. This paper investigates the application of Lean Production Thinking in the assembly technology, and proposes the concept of Lean Assembly. The Lean Assembly could be described as follows: Eliminating all wastes in assembly process through certain management tools and technologies. There are three sub goals of Lean Assembly: zero inventories, high flexibility, zero defects. What’s more, this paper studies several key technologies, such as assembly line balancing, mixed-model scheduling, part supplying, assembly cell, virtual assembly etc.
Status and Trends of Fixed Abrasive Polishing on Semiconductor
Authors: Zhao Y. , Zuo Dun Wen , Sun Yu Li
Published: January 2012

The necessity of fixed abrasive CMP in polishing semiconductor materials processing was analyzed. Compared the shortcomings of traditional free abrasive polishing with the advantages of fixed abrasive polishing, the applications of fixed abrasive polishing technology in semiconductor processing were described. A variety of fixed abrasive polishing pad production methods were introduced. The development trend of fixed abrasive polishing was prospected.
Determination of Constitutive Equation Parameters for Orthogonal Cutting through Pressure Bar Tests and FEA Method
Authors: Lan B. , Feng Ping Fa , Wu Z.J. , Yu D.W.
Published: January 2012

This paper proposes a method of determining the constitutive equation parameters of a Japanese type of alloy steel (SCM440H) for Finite Element Analysis (FEA) of orthogonal cutting, involving pressure bar experiments, orthogonal metal cutting experiments and FEA inverse identification. First, Split Hopkinson Pressure Bar (SHPB) experiments combined with Quasi-Static pressure tests were conducted, and after analyzing and processing the experimental data, one set of original constitutive constants was obtained; in the mean time, orthogonal cutting experiments were also performed to collect the cutting force data. Then the original constants were put into FEA software to simulate the cutting process. But comparison between the orthogonal cutting experimental and the simulation results revealed the inadequacy for the constants to predict cutting forces. To address this problem, an inverse identification method was employed to optimize the constants iteratively. And after a certain number of iterations, the ideal parameters for FEA of the orthogonal cutting process were finally determined.
FEA on the Roller Bracing Structure of Pellet Mill
Authors: Peng Jian Yun , Wu Kai , Shi S.J. , Peng B.B. , Sun Y.
Published: January 2012

In feed industry, the production efficiency is the main index to judge the performance of pellet mill. The stability of the pelleting process has an important influence on the production efficiency, and the rigidity of the roller bracing structure has a great effect upon the stability of the pelleting process. To improve the rigidity, two extra supporting shafts were usually used in the roller bracing structure system. According to the positions where the supporting shafts locate, the cross-sectional shape and area of the supporting shafts, six different kinds of supporting schemes were designed in this paper. Then the deformation of the roller in different supporting schemes were comparatively analyzed. The analysis results can provide an important reference to improve the stabilization of the pelleting process.
Advances in High-Speed Milling of Metal Matrix Composites
Authors: Ge Ying Fei , Xu Jiu Hua , Fu Y.C. , Zhang S. , Bian W.L.
Published: January 2012

Particle reinforced metal matrix composites (PMMC) possess many outstanding properties and are increasingly applied in automobile, aerospace, electronics and medical industries. However, PMMC is a typical difficult-to-machining material due to the rapid tool wear rate and excessive machining induced defects. Although large amount of investigations have been done on the conventional machining of PMMC, merely several researchers have dedicated themselves to the study of milling, especially high speed milling of this material. Within the milling studies, most researchers have selected the carbide coated or uncoated solid carbide tools whose tool life was not satisfactory for engineering application. The literatures review indicates that most researchers limited their study to sintering or casting SiCp/Al composites at the low or moderate cutting speed. Material produced by the in-situ reaction method or titanium matrix composites was seldom selected as the research object. The research content was limited to the effect of cutting parameters on the machined surface quality or cutting forces. It is suggested that high-speed milling with PCD tool should be conducted in order to improve the machined surface quality and material removal rate and decrease the machining cost. Tool life modeling, surface roughness prediction, cutting parameters optimization and high-speed milling data base and the expert system should be greatly noticed by the researchers.
Finite Element Simulation of the Mechanical Behaviour of Multifilamentary MMC during Wiredrawing
Authors: Taillard Roland , Rabhi Adi
Published: January 2012

The aim of the present paper is to report on a three-dimensional (3D) finite element modelling (FEM) of fabrication of multifilamentary composites using a restack bundle drawing process. The challenge arises from the complexity of the wire architecture. The reliability of the predictions ensues from the determination of the necessary mechanical data by means of the most realistic mechanical tests including billets drawing experiments. The simulations allow to determine response surfaces comparing the effects of the numerous fabrication parameters on the drawing force, the local stress triaxiality and the uniformity of deformation. The results agree with both experimental and theoretical data.
A New Method for Preparing Electrospinning-Derived Carbon Nanofiber Webs with Electrodeposited Sn-Sb Alloy as an Anode Material of Lithium Ion Batteries
Authors: Saatchi A.R. , Ghanbari E. , Saatchi A. , Raeissi K. , Tavanai H. , Mirza Khanlouei S.
Published: January 2012

Electrospinning is a straightforward and low cost method for producing carbon nanofiber (CNF) webs that have interrelated pores with high surface area. The process begins with electrospinning of polyacrylonitrile (PAN) on a Cu target collector. In current production methods, the PAN nanofiber web is taken off from the collector. But in order to omit extra stages of taking off the web from a conductive collector and later putting it back on, we will try to keep the web remained on the Cu collector plate through the carbonizing heat treatment and the electrodeposition, to later use the plate as the current collector of a LIB anode. This facilitates the handling of CNFs throughout the entire process that is now much more suitable for commercialization. This unique structure is very suitable for anode materials (AMs) of Lithium Ion Batteries (LIBs). It improves the kinetics of charge/discharge cycles by reducing lithium transport paths, and creates more stable electrochemical performance by providing space for volume expansions of lithium insertions in charging cycles. CNF webs can be used as AMs, demonstrating these advantages over conventional carbonaceous materials that have long been used as the preferred choice-in spite of having a comparatively low theoretical capacity. In this study we use the CNF web as a template for electrodepositing Sn-Sb alloy, to create the mentioned structural characteristics in a coated layer of an alloy with a higher capacity. The resulting composite is shown to have a higher capacity than the substrate CNF and a good cycling performance.
Development of Lean Alloyed Austenitic Stainless Steels with Reduced Tendency to Hydrogen Environment Embrittlement
Authors: Weber Sebastian , Martin Mauro , Theisen Werner
Published: January 2012

Hydrogen gas is believed to play a more important role for energy supply in future instationary and mobile applications. In most cases, metallic materials are embrittled when hydrogen atoms are dissolved interstitially into their lattice. Concerning steels, in particular the ductility of ferritic grades is degraded in the presence of hydrogen. In contrast, austenitic steels usually show a lower tendency to hydrogen embrittlement. However, the so-called “metastable” austenitic steels are prone to hydrogen environmental embrittlement (HEE), too. Here, AISI 304 type austenitic steel was tensile tested in air at ambient pressure and in a 400 bar hydrogen gas atmosphere at room temperature. The screening of different alloys in the compositional range of the AISI 304 standard was performed with the ambition to optimize alloying for hydrogen applications. The results of the mechanical tests reveal the influence of the alloying elements Cr, Ni, Mn and Si on HEE. Besides nickel, a positive influence of silicon and chromium was found. Experimental results are supported by thermodynamic equilibrium calculations concerning austenite stability and stacking fault energy. All in all, the results of this work are useful for alloy design for hydrogen applications. A concept for a lean alloyed austenitic stainless steel is finally presented.
Mechanical Spectroscopy Applications for Investigating Metallurgical Processes
Authors: Montanari Roberto , Bonetti Ennio
Published: January 2012

Mechanical Spectroscopy provides information on microstructural features of materials not obtained by other techniques. In general, it is used for investigating physical phenomena, however it can be very useful also for solving problems related to industrial processes. This work describes and discusses some applications of metallurgical interest.
Roll Casting of Clad Strip
Authors: Haga Toshio , Nakamura Ryoji , Kumai Shinji , Watari Hisaki
Published: January 2012

Roll caster to cast a three layers clad strip was invented and effect of casting conditions on the clad strip was investigated. Two vertical type twin roll casters were set at vertically tandem position to cast three layers clad strip. Roll speed, roll load (separating force), melt temperature and elements of the aluminum alloy were chosen as the experimental conditions to be investigated. The roll load (separating force) and elements of aluminum alloy were important factors to cast sound clad strip. The clad strip could be cast at the speeds up to 40m/min. Interface between the strips were clear and elements of each strip did not diffuse to other strip. The clad strip was not peeled off at the interfaces by continuous bending. Strips were strictly connected at the interfaces.
Formability of Magnesium-Lithium Alloy Sheet by Multi-Stage Deep Drawing
Authors: Harada Yasunori , Yamamoto Atsushi , Goto Takayuki , Nakamura Eiji
Published: January 2012

The formability of the magnesium-lithium alloy was examined by multi-stage deep drawing. Long cups of magnesium alloy were formed at ambient temperatures by multi-stage deep drawing processes. In multi-stage deep drawing, the magnesium-lithium alloy sheets were employed and a flat sheet blank is formed into a cylindrical by a punch. Various cups were drawn by exchanging the punch and ringed die. The die was flat in the first stage, and was taper without a blankholder in the subsequent stages. The effects of the ratio of blank diameter to punch diameter and blank thickness on the deep drawability were examined. It was confirmed that the Mg-Li alloy long-cups were successfully formed by a multi-stage deep drawing operation in cold.
Control of the Nugget Nanostructure of Mg96Zn2Y2 Welded by Resistance Spot Welding
Authors: Iwamoto Chihiro , Satonaka Shinobu , Kawamura Yoshihito
Published: January 2012

Recently, Mg96Zn2Y2 alloy was widely studied due to its excellent mechanical properties. These properties were considered to relate to the nanostructure of the alloy such as α-Mg matrix and bent long period stacking ordered (LPSO) structure. In this study, as the first step to the mechanical property control, we applied various spot welding methods to the Mg alloy to control the structure of the joints. The specimen used was an extruded Mg96Zn2Y2 alloy. The sheets were cut from this alloy rod for resistance spot welding. Three kinds of spot welding methods were applied to join the Mg alloy, such as spot welding with cover plates, long-time spot welding, and water-cooled spot welding. In the base metal, secondary phases extended along extruded direction at approximately 30μm intervals were produced in the α-Mg matrix. The secondary phase contained 14H-type LPSO structure. In the nugget of the joint welded with cover plates, a secondary phase was produced like a net in the α-Mg grain which was approximately 30μm in diameter. Both 14H-type and 18R-type LPSO were observed in the secondary phase. In the nugget produced by the long-time spot welding, a secondary phase tended to segregate to the grain boundary of the α-Mg grains. The structure of LPSO was 18R-type. In the water-cooled welding, strong directionality of the secondary phase texture was observed around the edge of the nugget. These results showed that the nugget nanostructure of Mg96Zn2Y2 dramatically varied depending on the above adopted methods of spot welding.
Microstructure and Mechanical Properties of Mg96Zn2Y2 Joints Welded by Resistance Spot Welding
Authors: Iwamoto Chihiro , Satonaka Shinobu , Kawamura Yoshihito
Published: January 2012

Mg96Zn2Y2 is widely studied due to its high tensile yield strength and elongation. These excellent properties were considered to relate to the nanostructure of the alloy such as fine-grained α-Mg matrix and bent long period stacking ordered (LPSO) structure. In order to extend the application of this Mg alloy, development of the welding technique is indispensable. In the light of the reliability and productivity, resistance spot welding is an attractive method to join this Mg alloy. In this study, we joined the Mg alloys by the resistance spot welding with cover plates. Mechanical properties and structures of the nugget of the joints were investigated. In the case of the joints welded with cover plates, the welded region of the Mg alloy sheets were covered with steel plates to supply adequate heat for welding. Joints of extruded Mg96Zn2Y2 were obtained at relatively low welding current. The tensile strength of Mg96Zn2Y2 alloy was higher than that of the commercial Mg alloy AZ31B joints. Mg96Zn2Y2 base alloy had extended LPSO phase along extruded direction in α-Mg grains. At the nugget, net-like secondary phase was produced in the Mg grains. The relationship between the microstructure in the joints and mechanical properties were discussed.
Creep Behavior and Microstructures in Grain Boundary Strengthened Mg-Al-Ca Thixomolded® Alloys
Authors: Suzuki Mayumi , Shibata Akihiro , Maruyama Kouichi
Published: January 2012

The microstructures of thixomolded® (TM) Mg-Al-Ca alloys consist of α-Mg and eutectic compounds along grain boundaries. Misch metal (Mm) addition to TM Mg-Al-Ca alloys makes precipitates within α-Mg matrix and their number density and size depend on heat-treatment conditions. The small addition of Mm can keep the network-like grain boundary covering and the improvement of microstructure stability during creep. On the other hand, excessive Mm addition causes the deterioration of creep strength. The grain boundary coverage decreases with increasing Mm content due to the formation of coarse spherical Al-Mm based intermetallic compounds. Creep strength is significantly affected by both of the grain boundary coverage and the morphology of eutectic compounds along grain boundaries.
Non-Isothermal Crystallization Kinetics of Co67Fe4Cr7Si8B14 Amorphous Alloy
Authors: Hasheminezhad S.A. , Haddad-Sabzevar M. , Sahebian S.
Published: January 2012

Non-isothermal crystallization kinetics of Co67Fe4Cr7Si8B14 amorphous ribbons was studied by differential scanning calorimetry (DSC) technique under 10, 20, 30, 40 and 80 °Cmin-1 heating rates. It is found that Co67Fe4Cr7Si8B14 amorphous alloy exhibits two-stage crystallization on heating. The two crystallization peaks shift to higher temperatures with increasing heating rate. The apparent activation energies (EC) for the first stage of crystallization were determined as 443.44 and 434.47 kJmol-1 by using the Kissinger and Ozawa equations, respectively. Frequency factor (A) estimated to be 1.084×1026 s-1 using Kissinger equation. Kinetics parameters such as Crystallization exponent (n) and dimensionality of growth (Ndim) were determined using JMA (Johnson-Mehl-Avrami) method. Details of the nucleation and growth behaviours during the non-isothermal crystallization were studied in terms of local activation energy EC(x) by the OFW (Ozawa, Flynn and Wall) method. Also the activation energy for nucleation (En) and growth (Eg) separately estimated.
Pressure Sensitivity of Plasticity in Metallic Glasses below Glass Transition: A Literature Review
Authors: Keryvin Vincent , Brest Jean Sebastien , Longere Patrice , Anguet Adrien
Published: January 2012

This paper deals with the pressure dependence of plasticity in metallic glasses below glass transition. Recent results indicate that some metallic glasses have such a dependence and that it increases with temperature (Keryvin et al., Phil. Mag., 88, 1773, 2008). We investigate the possibility that such a situation could be a common feature for all metallic glasses by performing a literature review. Results indicate that it is not strightforward to draw decisive conclusions.
Manufacture and Industrial Application of Fe-Based Metallic Glasses
Authors: Kim S.W. , Namkung J. , Kwon Ohjoon
Published: January 2012

Metallic glass alloys have been considered as attractive materials due to their excellent mechanical and magnetic properties. However, commercial application of metallic glasses has been limited not only because of high production cost, but because of low market demands. A critical production cost factor was raw material since ferrous metallic glasses were made from high purity electrolytic iron. An idea to reduce the cost was to utilize the raw materials which were taken directly from molten iron and steel manufactured at the existing steel plants. Investigations have been performed to find whether metallic glasses made of molten iron and steel demonstrated appropriate mechanical and magnetic performance. Pilot scale equipments were designed to produce amorphous metallic fibers and strips continuously under the atmospheric condition. Process conditions were optimized by controlling process variables such as alloying and nozzle design, feeding temperature, speed and so on. The glass formability was tested by XRD and DSC analysis. Possibilities of application of Fe-based metallic glasses to reinforced concrete were also evaluated. It was confirmed that a small addition of metallic glass fibers in concrete increased the mechanical performance compared to that of commercial concrete reinforced with steel wires. In addition, amorphous strips were manufactured to apply them to the transformer core. It has been demonstrated that the magnetic properties were equivalent to those of commercial products.
Homogeneous Abnormal Grain Growth in Polycrystalline Materials
Authors: Abbruzzese Giuseppe Carlo , Forzanti Cristina
Published: January 2012

The controversy about the start up of the abnormal growth as heterogeneously engendered in the microstructure or produced by peculiar continuous incubation process has still not been solved. In this work the statistical theory of grain growth has been applied to treat the case of grain growth in the presence of an homogeneously unstable Zener drag. By the simulations presented it will be shown as abnormal grain growth is a result out of a continuous and homogeneous process without requiring any heterogeneity in the microstructure presumed to give local advantages to some grains. The mechanism by which during an incubation period the preconditions for the unstable growth are built up in the microstructure is clarified and discussed. Moreover the peculiar shape of Grain Size Distribution (GSD) approaching the “structural instability” will be also analytically defined and compared with experimental results obtained in a grain oriented Silicon Iron just before the onset of abnormal grain growth.