bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistivity-Temperature Feature of Ga36.5Sb63.5 Melt
Authors: Deng Yan Bo , Geng Hao Ran , Sun Yu Jie , Teng Xin Ying , Wang Yan
Published: March 2010

In the present work, the resistivity of Ga36.5Sb63.5 alloy during cooling process was studied by the method of DC Four electrodes . The result of the experiment showed that there is an anomalous point at 710°C－735°C on the resistivity-temperature curve of Ga36.5Sb63.5 melt. At the same time, The relevance of the resistivity and the liquid structure of the alloy was analyzed. The physical properties of Ga36.5Sb63.5 alloy melt was discussed.
An Investigation on the Hydrogen Content in Al-12Si Alloy Melt
Authors: Xu Zheng Bin , Zou Yong Zhi , Wang Wen Chao , Zeng Jian Min
Published: March 2010

This present work investigate the hydrogen content in Al-12Si alloy at different holding temperatures of 993K, 1023K, and 1053K and under different ambient relative humidity 30%RH, 50%RH, 80%RH. The relationship of the hydrogen content with atmosphere relative humidity and the reaction time was investigated. A HYSCAN II analyzer was used to evaluate the hydrogen content in aluminum melts. The experimental results show that the hydrogen content increased with the holding temperature and the relative humidity. At the temperature 1053K, the hydrogen content has an inverse change. The hydrogen content is more depend on the liquid structure than physical mass transfer and chemical reaction because of the sudden change in liquid microstructure. A group of kinetic regression equations of the hydrogen absorption in Al-12Si melts was obtained.
The Oil Lubricated Sliding Wear Behavior of In Situ TiB2 Partical-Reinforced Al-10Sn Matrix Composites
Authors: Cui Guo Ming , Li Xing Xia , Zeng Jian Min
Published: March 2010

Al-10Sn matrix composites reinforced by TiB2 particles were fabricated by Mixed Salt Reaction in situ synthesis process. The oil lubricated sliding wear tests of composites and matrix alloy were conducted on a small thrust ring versus disc wear testing machine at room temperature under different applied loads and the wear surfaces were observed using SEM. The results indicate that the coefficient of friction, friction temperature, and wear weight loss increase with the increase of applied loads, but compared with matrix alloy, the composites exhibit better anti-friction property and higher wear resistance. The analysis of wear surface suggests that light ploughing is predominant for composites and matrix alloy at low loads, and ploughing is still predominant for composites at high loads, but adhesion and delamination are predominant for matrix alloy at high loads
Effect of Lubricant on Surface Rolling Contact Fatigue Cracks
Authors: Farhangdoost Khalil , Kavoosi Mohammad
Published: March 2010

This study performed the finite element analysis of the cycle of stress intensity factors at the surface initiated rolling contact fatigue crack tip under Hertzian contact stress including an accurate model of friction between the faces of the crack and the effect of fluid inside the crack. A two-dimensional model of a rolling contact fatigue crack has been developed with FRANC-2D software. The model includes the effect of Coulomb friction between the faces of the crack. The fluid in the crack was assumed not only to lubricate the crack faces and reduce the crack face friction coefficient but also to generate a pressure.
Effects of Al and Zn on the Microstructure and Mechanical Properties of Magnesium Alloys
Authors: Li Jing Yuan , Du Xiao Lei
Published: March 2010

Two groups of magnesium alloys with various Al and Zn components are studied in this paper. One group of alloys are constant Al content of about 6% and various Zn content from 0 to 3%, another group are constant Zn content of about 0.4% and various Al content from 0 to 6%. The microstructures and mechanical properties of these alloys are investigated in as-cast and homogenized at 380°C for 15h. The results show that the tensile strength increases but yield strength decreases after homogenizing treatment. It can also be found that the morphology of second phrase and the size of grain exert the more effect on the mechanical properties than Zn content does. The alloys with uniform, fine and non-dendrite microstructure exhibit both high strength and elongation regardless of Zn content. On the other hand, the tensile strength and yield strength elevate significantly as Al content increases, and the elongation has a peak value in Al content of about 1.90%. The results show that the as-cast magnesium alloys with Al content of 5.6~6.0% and Zn content of 0.6~1.0% exhibit the best comprehensive mechanical properties.
Study on Hot Plasticity and Microstructure of Mn18Cr18 High Nitrogen Austenitic Stainless Steel
Authors: Chen Yu Lai , Feng Shu Fei , Zhang Jin , Li Jing Yuan
Published: March 2010

The hot plasticity of Mnl8Crl8 high nitrogen austenitic stainless steel is studied using the thermal simulated test in this paper. In addition, microstructural evolution and precipitate morphology are investigated through optical microscope(OM), scan electron microscope(SEM), X-ray diffraction(XRD) and Electron probe micro-analyzer(EPMA). The results show that the area reduction of Mnl8Crl8 steel varies in a “V” shape in the elevated temperature region. It means that plasticity of Mnl8Crl8 steel is relatively low when the deformation temperature is in 1000~1100°C, whereas an excellent plasticity can be obtained in 850~950°C and 1150~1200°C. The peak value of area reduction appears at 1050°C. The analysis of SEM on fracture morphology indicates that the inter-granular fracture and dimple fracture occur at 1050°C and 1150°C respectively. The results of OM exhibit that the dendrite precipitation occurs while the precipitate in grain boundary solutions as the temperature increasing and the grain coarsens immensely beyond 1000°C. However, dendrite precipitate solutions into the austenite matrix at further elevated temperatures. It causes the plasticity substantial improvement in 1150~1200°C. Moreover, the observed precipitation of the steel is confirmed to be Cr23C6 by XRD and EPMA.
A Double-Parameter K~J Fracture Criterion for Epoxy Asphalt Concrete
Authors: Qian Zhen Dong , Luo Sang , Chen Chun Hong , Li Zhi , Chen Lei Lei
Published: March 2010

The epoxy asphalt concrete is extensively used as paving material for long-span steel bridges in China. But mode I crack, which is most prominent cracking pattern for the pavement, often appears on the pavement surface. Therefore, the stress intensity factor K and J-integral were adopted to analyze fracture properties of single-edge notched three-point bending beams. The influence of temperature on the two parameters was studied. The analyses indicate epoxy asphalt concrete exhibits ductile fracture property at 5~25°C and brittle fracture property at -15~5°C. It is also found that fracture property of epoxy asphalt concrete is better than other kinds of bituminous concrete. Finally, a double-parameter K~J fracture criterion is founded for the epoxy asphalt concrete and provides basis for anti-cracking design and repair of cracks of the pavement.
Experiment and FEM study on Uniaxial Tensile of SiCp/Al
Authors: Qin Liang , Zhang Ke Shi , Geng Xiao Liang
Published: March 2010

SiC particle reinforced aluminum metal matrix composites (SiCp/Al) were prepared by powder metallurgy method, and the volume fraction was 5% with size of 3.5 micron and 10 micron. Uniaxial tensile experiments were carried out and the fracture modes were observed. The results demonstrated that the SiC particles in matrix might improve the strength and elastic modulus of the material, but the plastic deformation ability of the material decreased obviously. Based on SEM observation on the microstructure, the boundary cell model (boundary cell finite element method, BCFEM) was established to consider the particle debonded from its surroungding matrix. The particle debonding described by nucleation and growth of voids in matrix，which was investigated using GTN(Gurson-Tvergaard-Needleman) model. The BCFEM model was valid to describe the damage behavior due to the accurate characterization for microstructure of the model.
Tempering Resistance of a New Type of Tool Steels Used in Magnesium Die Casting Machine
Authors: Wang Yan Qing , Huang Xin Min , Yan Guang Hua , Qin Xing Guo , Yang Ming , Chu Zuo Ming , Jin Kang
Published: March 2010

The tempering resistance in double tempering of a new type of tool steels used in magnesium die casting machine quenched at 1080°C, 1120°C and 1150°C respectively was investigated. 4 hours of first tempering and double tempering at 600°C, 630°C, 660°C, 690°C and 720°C are applied. The minimum hardness value is 53.4HRC quenched at 1150°C and then tempered. The decomposition of tempered martensite lath was retarded after adding a number of alloying elements such as Cr, Co, W, Mo, V, according to observations by transmission electron microscopy. It also shows that the fine dispersion secondary carbide precipitates along the martensite grain surface and grain boundary. The use of X-ray diffraction has revealed that secondary carbides precipitates takes the form of M6C carbide and the retained austenite has transformed to martensite completely quenching at 1150°C. These microstructures would lead to the better tempering resistance.
Influence of HLB Parameters of Surfactants on Properties of Magneto-Rheological Fluid
Authors: Du Cheng Bin , Chen Wei Qing , Wan Fa Xue
Published: March 2010

The hydrophilic-lipophilic balance (HLB) parameters of surfactants have a significant effect on properties of surfactants and determine the effects of surfactants. The magneto-rheological fluid (MRF) is prepared by using the two typical HLB parameters of surfactants including Polyethylene Glycol and oleic acid in order to improve the property of MRF. Polyethylene Glycol (PEG) whose HLB parameter is 20 has strong hydrophilic. Oleic acid whose HLB parameter is 1 has strong lipophilic. The results indicate that magnetic properties of magnetic particles and rheological properties of MRF can hardly be changed by adding surfactants. The sedimentary stability of MRF adding lipophilic surfactants is superior to that of MRF adding hydrophilic surfactants, and the stability of MRF adding two surfactants increases significantly.
Experimental and Numerical Evaluation of the Vibration Fatigue of Small Bore Pipe in PWR
Authors: Xue Fei , Wang Zhao Xi , Lin Lei , Ti Wen Xin , Gong Ming Xiang , Liu Peng , Shu Guo Gang
Published: March 2010

The purpose of this paper is to evaluate the vibration of the small bore pipe in nuclear piping under the fatigue loading due to flow fluctuation. The vibration speeds of the pipe-lines were measured to get the effective velocity which is found larger than the allowable value calculated from EDF evaluation method. To perform the piping vibration assessment and construction, the natural shape and the vibration stress at the socket weld position was evaluated by finite element analysis with ABAQUS. From the linear cumulative damage theory, the fatigue life is predicted with the results that lower than the designation level. According to the position of the maximum vibration speed calculated from FEA simulations, the valve is fixed by the rigid support. The natural frequency and the corresponding mode shape are discussed with much lower vibration velocity and vibration stress.
Wear Behavior of Cr2O3/Cu Composite under Electrical Sliding
Authors: Song Ke Xing , Guo Xiu Hua , Wang Yong Peng , Wang Qing
Published: March 2010

The Cr2O3/Cu composites with different Cr2O3-content performed in this paper were prepared by surface internal oxidation of Cu-Cr solid alloy. The Cr2O3/Cu composite wires were slid against a copper-based powder metallurgy strip under unlubricated conditions. The wear behavior of Cr2O3/Cu composite was researched under different currents from 0-50A and sliding distance from 0-72Km. Worn surfaces of the Cr2O3/Cu composite were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The results indicate that the wear rate of Cr2O3/Cu composite increases with the increase in electrical current and sliding distance. The wear rate increases abruptly at the beginning and smoothly subsequently. And the variety of electrical currents has slight influence on the wear rate. The wear rate of the Cr2O3/Cu composites decreases with the increase in Cr2O3-content. The wear rate of 0.478 Cr2O3/Cu composite is 2-3 times that of 1.25Cr2O3/Cu composite at the same experimental conditions. Abrasive wear and electrical erosion wear are the dominant wear mechanisms during the electrical sliding wear processes.
Effect of Rare Earth Oxide on Sintering and Crystallization of Fused Quartz Ceramic Materials
Authors: Ma Fei , Wang Zhi Fa , Bu Jing Long , Wang Rong Lin , Chen Si Si
Published: March 2010

Fused quartz ceramic was prepared in reducing atmosphere at 1300°C, 1400°C and 1500°C for 1h with fused quartz powder as raw materials (size<0.2mm). The effect of La2O3, Nd2O3, Er2O3 and Yb2O3 on crystallization and sintering of the materials were researched by measurements of apparent porosity, bending strength and thermal expansion rate (RT~1200°C), and analyses of XRD and SEM. The results showed that La2O3 and Nd2O3 have a few facilitating effect on sintering, Er2O3 and Yb2O3 have better facilitating effect on sintering of fused quartz ceramic samples, samples ER and YB have lower apparent porosity and higher bending strength and more compact microstructure. So additives La2O3, Nd2O3 and Er2O3 have a few effect of inhibiting on crystallization, Yb2O3 has better effect of inhibiting on crystallization of fused quartz. Sample YB has least thermal expansion rate.
Characterization of Hyperelastic Dielectric Elastomer Based on Biaxial Tensile Bench
Authors: Luo Hua An , Wang Hua Ming , Zhu Jian Ying , You You Peng
Published: March 2010

Usually model parameters from uniaxial experiments are not suitable for dielectric elastomer under biaxial loading condition. To characterize the mechanical behavior of dielectric elastomer, a biaxial tensile bench is established, on which uniaxial tests can be performed too. On the basis of the analysis of viscous effect of elastomer, experimental condition for data acquirement is determined. Then equi-biaxial and uniaxial experimental data are obtained to fit three constitutive models, i.e. Mooney-Rivlin, Yeoh and Ogden model. Also, least square minimization method is used to obtained model parameters, which are applicable to both uniaxial and equi-biaxial experimental data.
Study on Doping and Microwave Permittivity of SiC Powders
Authors: Liu Xiao Kui , Nie Chao Yin , Luo Fa , Zhou Wan Cheng , Li Shuai Fang
Published: March 2010

SiC powders doped with aluminum in the method of thermal diffusion were prepared at 1800°C, 1900°C, and 2000°C respectively, and the permittivity and structure of SiC powders before and after thermal diffusion were investigated. There is no obvious change in the morphology and phase structure before and after the doping processes. Both the real and the imaginary parts of the permittivities of the Al-doped SiC powders are improved much more than those of the original SiC powders, and increase with the doping temperatures. It is believed that, the high values of both the real and the imaginary parts of the permittivity are due to electric relaxation and conductivity losses as result of aluminum atoms doped in silicon carbide lattice.
The Hereditary Feature for Preferred Orientation in Ferritic Stainless Steel
Authors: Liu Yan Dong , Yang Yi Qiao , Bi Hong Yun , Zuo Liang
Published: March 2010

In this paper, the texture and micro-orientation of FSS (Ferritic Stainless Steel) during hot rolling, cold rolling and annealing were studied by using x-rays and EBSD technology. The results shown that as cast ingot of FSS was compose of random orientations equiaxed grains and <001>∥ND columnar grains; after hot rolling, the preferred orientation of <001>∥ND columnar grains of as cast ingot obtained inherits, the fiber texture was obvious stronger than that of equiaxed grains; during cold rolling, the initial <001>∥ND columnar grains turn to  fiber texture,  fiber texture can not be found.
Penetration of Cone-Nose Projectile to the Laminated Composite Aluminum Alloy Foam Target
Authors: Sha Feng Huan , Zhang Nian Mei , Yan Xiao Peng , Yang Gui Tong
Published: March 2010

A theoretical study is presented herein on the penetration of the laminated composite aluminum alloy foam target struck normally by conical-nosed projectiles. Two layers were arranged according to the density of the respective foam; configuration 1 consisted of 10mm/semi-infinite continuous foams and configuration 2 consisted of 20mm/ semi-infinite continuous foams. The dynamic cavity expansion theory is applied to formulate analytical model. The penetrating process can be divided into 6 stages. The resistance equations during every stage are derived. Penetrating depth of projectile are analyzed. The effect of initial velocity, mass density of foam material and the thickness of the upper layered foam on the penetration resistance are investigated. It is found that composite target have a higher penetrating resistance than the monolithic foam material target of equal mass. The analytical results show that configuration 1 outperformed configuration 2 in regards to their penetrating resistance. The thickness of the upper layered foam within 5-20mm has significant influence on penetrating depth. The energy absorption capacity of the composite target material is evaluated.
Creep Continuum Damage Analysis for a Pressurized Thick Wall Circumferentially Welded CrMoV Steel Pipe at 640°C
Authors: Jia Kun Rong , Yue Zhu Feng
Published: March 2010

The failure assessment for thick wall CrMoV steel pipes circumferentially welded at 640°C was studied using the Finite Element (FE) method under close-ended, open-ended and axial compression conditions, respectively. The life and position of failure, redistribution of stress on the welds and damage variations were obtained using damage modeling. Since there is a distinct mismatch of mechanical properties in parent material, weld material and heat affect zone, variations of damage with time, stress redistribution and failure life in each zone are different. The FEM results show that the weakness of the welds is the heat-affected zone (HAZ) where the hoop stresses increase sharply in the tertiary stage of creep. The maximum of damage of the welds lies on the inner surface of in the weld zone when failure occurs. The information is useful for assessing the performance of practical service welds in power plants pipe work.
Effects of Die Temperature of SSS Die Casting on the Microstructure and Mechanical Properties of ADC12 Aluminum Alloy
Authors: Ji Lian Qing , Shao Jian Min , Xiang Guo Quan , Qian Li
Published: March 2010

In the present paper, the effects of different die temperatures on microstructures and mechanical properties of aluminum alloy ADC12 at Super Slow Speed (SSS) die casting have been investigated, in order to optimize the die-casting process and its parameters. The results show that under SSS experimental condition, the density of castings is higher than that of general die castings. Die temperature has the best value, when the die temperature is 150 °C, smaller dendrites are distributed in the hardened surface layer, and the eutectics structure of and Si changes from needle-like structure into herringbone structure. The properties of the die casting are significantly influenced by the die temperature, the optimum die temperature is 150 °C.
Strain Amplitude Dependence of Damping Capacity in High Damping Mg-Based Alloys Continuously Extending to Microplastic Strain
Authors: Wan Di Qing , He Bo Lin , Wang Jin Cheng , Yang Gen Cang
Published: March 2010

An investigation on low frequency strain amplitude dependence damping characteristic of as-cast high damping Mg-based alloys continuously extending to microplastic strain was carried out. Two-stage damping behavior via strain amplitude was particularly reported. The first is the strain amplitude strongly dependent part due to breakaway loss and the second is the strain amplitude weakly dependent part due to microplastic deformation loss, which is also frequency dependent. The damping mechanism is discussed in detail.
Mechanical Properties of Ti-Doped DLC Multilayer by Pulse Cathodic Arc Deposition
Authors: Ren N. , Zhao D.C. , Ma Z.J. , Xiao G. J. , Wu S.H.
Published: March 2010

To reduce the internal stress and obtain thicker DLC film, a multilayer structure DLC comprised of Ti-doped nanolayer were deposited on Titanium alloy substrate by pulse cathodic arc technology, the Ti content is decreased from bottom to top layer. And the surface layer is carbon deposited with ion–assist deposition. The chemical composition of the films was determined using X-ray photoelectron spectroscopy (XPS). The film structure was characterized by Raman spectroscopy. Other properties of the films are evaluated by Dektak 8 Stylus Profilometer, nano-hardness tester and reciprocating sliding wear tester. And the thickness, hardness, and friction coefficient of two samples are 2.2μm, 1.5μm, 5200Hv, 5500Hv, and 0.09, respectively. The internal stress, calculated by Stoney’s equation, is 2.2GPa, 2.1GPa. And the adhesion strength is 40N/mm2, 35N/mm2.
Application and Research on the Cold-Drawing Steel Wire Annealing Process under the Pulse Current
Authors: Sun Hong Yi , Ma Wen Qi , Zhang Wei , Shu Chang , Ma De Cai , Yue Yan Xing
Published: March 2010

The paper explores in depth a new annealing technology -electric pulse annealing treatment. To improve the disadvantage of the traditional annealing, such as, low efficiency, high energy consuming, polluting the environment, badly oxidation of the product surface, and so on, a new technique that carrying through the annealing and soften treatment with pulse electric current on the Q235 steels was put forward in the text. The experimental device was designed and the parameter was optimized in this assay. And also, the annealing mechanism was explored according to the analyzing of the metallurgical structure and the changing of the property of the steel wires. It is found through the analysis that the pull-out resistance of the wire is significantly decreased and the elongation is improved significantly after electric pulse treatment, and the effect of using high-strength pulse current treatment about 25 seconds (temperature up to 390°C) is similar to the effect with traditional annealing or even reduce the initial temperature.
The Effect of Entrance Temperature on Texture and Microstructure Development in Cold Mill Rolled 85/15 α-Brass
Authors: Chen Yong Jin , Guo Ran , Shi Q. , Wang Hua , Chiu Y.
Published: March 2010

With the entrance temperature at 300°C, cold mill rolling produced deformation texture transition from brass type to copper type in worked 85/15 α-brass. From the texture and TEM scale microstructure evidence, it is suggested that, rather than deformation twinning, recovery and easy cross slip favor in the deformation process, as the interior working temperature falls into the texture transition range proposed by Tranchant.
Investigation on Fatigue Limit Based on the Series Complicated Notches for Structural Steel
Authors: Wang Sheng Wu , Wen Ai Ling , Nishida Shinichi , Wang Wei Da
Published: March 2010

The rotating bending fatigue tests have been carried out to investigate the fatigue limit of specimen with double-notch which is constructed by the step and the blind hole, and the effect of stress concentrations at the double-notched bottoms on the fatigue limits are analyzed using three-dimensional elastic finite element method (3D-EFEM). There are fatigue limits of 17 groups on the single-notched specimen and double-notched specimen obtained in the fatigue tests. The stress field interactions are discussed between the stress field by the blind hole notch and the stress field by step using 3D-EFEM. The results obtained in this study are as follows: The fatigue limit of the double-notch specimen is insensitive to the distance between the blind hole and step for the low carbon structure steel with better ductility; while, for the high-strength steel, superposition and intensification of the stress concentration by the blind hole and step mutually may be avoided, and their adverse effects on the fatigue strength may be become to minimal, when taken appropriate distance between the blind hole and step. The results are significant for engineering design of the multi-notched parts, and studying fatigue strength theory.
Formation of Non-Dendritic Microstructure of Semi-Solid Magnesium Alloy by Introducing Gas Bubbles
Authors: Li Jiqiang , Zhang Lei , Dong Xuan Pu , Fan Zi Tian , Liu Wen , Zhang Zhao
Published: March 2010

A new technique of introducing gas bubbles during isothermal period of AZ31 magnesium to prepare semi-solid slurry has been reported. The effect of resting time after stirring on the microstructure of the slurry is discussed. Results show that the dendrites and liquid phase reduced, the non-dendritic grains grew up and became spheroidized. A fully grain-refined structure can be obtained with 60s resting time.
Description of Recalescence in Bulk Undercooled Alloys
Authors: Yang W. , Liu Feng , Yang Gen Cang
Published: March 2010

Assuming phenomenological thermal flow balance and solute conservation, a numerical model was proposed for recalescence in bulk undercooled alloy. During the calculation, the evolution of residual melt temperature and concentration is solved as function of the transformed solid fraction. After quantitative thermodynamic calculations, a transition from non-equilibrium to equilibrium process can be described by the change of liquid/solid Gibbs energy difference. The proposed model has been applied to Cu-Ni solid solution and Fe-B hypereutectic alloy. The predicted post-recalescence temperature TR agrees well with the experimental results.
Clustering of Arsenic Atoms in Silicon during Low-Temperature Annealing
Authors: Velichko Oleg , Burunova Olga
Published: March 2010

Simulation of arsenic clustering in Si at a temperature of 750 degrees Celsius has been carried out. It has been shown that considering the formation of singly or doubly negatively charged clusters that incorporate one or two arsenic atoms and point defects, one obtains a good fit to the measured values of electron density. It is supposed that we have the initial stage of clustering, when the concentration of complexes with one arsenic atom incorporated is high enough and the diffusion of these mobile particles provides for the formation of more stable clusters incorporating two arsenic atoms.
Effect of Current Density on Composition and Microstructure of Si Diffusion Layer by Electrodeposition
Authors: Yang Hai Li , Zhang Yu Zhu , Li Yun Gang , Tang Guo Zhang , Jia Kuo
Published: March 2010

A Si diffusion layer on grain-oriented low-silicon steel substrates was produced by pulse electrodeposition in KCl-NaCl-NaF-SiO2 molten salt and the effect of current density upon the composition and microstructure of the siliconized layer was investigated. The results showed that by glow discharge spectrometry (GDS), the change of Si content of siliconized layers was similar in the range of 20-60 mA/cm2. Si content in the surface was maximum, and then dropped sharply within the surface layer (< 7 m). The Si content remained nearly constant in the middle part of the siliconized layer. The content of Si near to the substrate decreased relatively slowly. The Si content in the surface and the layer thickness increased with increasing current density. Cross-sectional observations revealed that the Si diffusion layers had a two-layer structure: the top layer composed of columnar grains grown perpendicularly to the substrate surface and a transition layer with equiaxed grains was close to the substrate. In addition, the thickness of the layer was too small when the current density was 20 mA/cm2, while the layer became more porous as the current increased from 40 to 60 mA/cm2 according to SEM observations. The optimum current density for deposition was 30 mA/cm2.
Stress-Corrosion Cracking in Unidirectional GFRP Composites
Authors: Sekine Hideki , Beaumont Peter W.R.
Published: March 2010

A micromechanical theory of macroscopic stress-corrosion cracking in unidirectional glass fiber-reinforced polymer composites is proposed. It is based on the premise that under tensile loading, the time-dependent failure of the composites is controlled by the initiation and growth of a crack from a pre-existing inherent surface flaw in a glass fiber. A physical model is constructed and an equation is derived for the macroscopic crack growth rate as a function of the apparent crack tip stress intensity factor for mode I. Emphasis is placed on the significance of the size of inherent surface flaw and the existence of matrix crack bridging in the crack wake. There exists a threshold value of the stress intensity factor below which matrix cracking does not occur. For the limiting case, where the glass fiber is free of inherent surface flaws and matrix crack bridging is negligible, the relationship between the macroscopic crack growth rate and the apparent crack tip stress intensity factor is given by a simple power law to the power of two.
Fracture Toughness of Whisker Reinforced Ceramics
Authors: Katagiri Makoto , Kumaki Akihiko , Izumi Yoshito , Suzuki H. , Sekine Hideki
Published: March 2010

By use of a probabilistic fracture model, a numerical simulation method for deformation and fracture behavior of whisker reinforced ceramics is developed first. A crack in whisker reinforced ceramics is regarded as the crack with a cohesive stress acting on the crack surface, and then the tension-softening relation is derived on the basis of a micromechanical study. After the numerical simulation method is constructed by incorporating the tension-softening relation in an FEM scheme, we simulate the load-load point displacement relationship for an edge-cracked bend specimen of a SiC whisker/alumina composite. The fracture toughness determined from the simulated maximum load is consistent with that obtained from experiment.
Load Carrying Capacity of Notched CFRP Laminates
Authors: Suzuki H. , Kinugawa S. , Sekine Hideki
Published: March 2010

On the basis of a micromechanical study, a method for evaluating load carrying capacity of notched CFRP laminates is developed. The damage zone at a notch tip in CFRP laminates is modeled as a fictitious crack with a cohesive stress acting on the crack surface. Then, applying the Weibull weakest link theory to the strength of surviving fiber bundles on the crack surface, we derive the relationship between the cohesive stress and the crack opening displacement, i.e., the tension-softening relation. By incorporating it in a BEM scheme, the load-displacement relationship is simulated. The simulated result for notched CPRP laminates is compared with experimental ones, and it is found that the simulated and experimental results of load carrying capacity are consistent.
Effect of Matrix Hardening on Tensile Strength of Alumina-Fiber Reinforced Aluminum Matrix Composites
Authors: Okabe T. , Nishikawa M , Takeda Nobuo , Sekine Hideki
Published: March 2010

This paper examines the stress distribution around a fiber break in alumina-fiber reinforced aluminum matrix (Al2O3/Al) composites using finite element analysis and predicts the tensile strength using tensile failure simulations. In particular, we discuss the effect of the matrix hardening on the tensile failure of the Al2O3/Al composites. First, we clarify the differences in the stress distribution around a fiber break between an elastic-perfect plastic matrix and an elastic-plastic hardening matrix using finite element analysis. Second, the procedure for simulating fiber damage evolution in the Al2O3/Al composites is presented. The simulation incorporates the analytical solution for the axial fiber stress distribution of a broken fiber in the spring element model for the stress analysis of the whole composite. Finally, we conduct Monte Carlo simulations of fiber damage evolution to predict the tensile strength of the Al2O3/Al composites, and discuss the effect of matrix hardening on the tensile strength of the Al2O3/Al composites. Coupled with size-scaling analysis, the simulated results express the size effect on the strength of the composites, which is seen in experimental results.
Study on Machining System of Precision Micro Abrasive Water Jet and Polish Experiment
Authors: Liu Zeng Wen , Huang Chuan Zhen , Wang Jun , Zhu Hong Tao , Li Quan Lai
Published: March 2010

This paper conducts a study on a precision micro abrasive waterjet (PMAWJ) machining system. A new kind of precision micro abrasive water jet system is designed and tapped. The flux and the flow velocity of the PMAWJ system are tested by experiments. Using the micromachining system, a group of polishing experiments is conducted for two kinds of hard-brittle materials such as silicate glass and silicon nitride. The results show the feasibility and the advantage of the PMAWJ machining system for polishing hard-brittle materials.
Application of Clustering Regression to Thermal Error Modeling of NC Machine Tool
Authors: Qi Xiao Ni , Guo Qian Jian
Published: March 2010

The thermal distortion of YK3610 hobbing machine is analyzed. The concept of clustering analysis is proposed and implemented on the gear hobbing machine. The model was used in the experimental of thermal error compensation. The results show that the thermal error compensation control system can reduce thermal errors significantly and the prediction accuracy of the thermal error model is high enough.
Experiments on High-Speed and Dry Cutting with PCBN Tool
Authors: Yang Hai Dong , Qing Zhen Hua , Xie Feng , Zhang Chong Gao
Published: March 2010

This paper deals with the High-speed Hard and Dry Cutting mechanism of hardened alloy-steel with PCBN tool: the cutting speed and workpieces temperature and tool wear are being discussed in different cutting speeds when cutting alloy-steel 42CrMo. After the workpiece temperature measured by ThermaVision, it is proved that the workpiece temperature was not high and changed little. Through the SEM and EDS analyses for chip and tool wear, it is proved that PCBN tool is suitable for High-speed Hard and Dry Cutting. It is suitable for PCBN tool to cut hardened alloy-steel 42CrMo instead of grinding.
A Study on Critical Heat Flux in Grind-Hardening
Authors: Zhang Zhen Guo , Ge Pei Qi , Zhang Lei , Bi Wen Bo
Published: March 2010

The hardening characteristics could be achieved by a proper selection of the grinding conditions. It is necessary to keep the heat flux above the critical limit for the film-boiling and the austenitization within the grinding zone. In this paper, a critical thermal analysis was presented to calculate the critical heat flux, following the methods for predicting thermal damages in creep grinding and high efficient grinding. The appearances of the hardening phenomena were predicted for dry grinding and wet grinding. It also can guide the selection of the grinding conditions. Theoretical analysis was verified by the experiments. Measurements are found to be in good agreement with the theoretical predictions.
FEM-Based Dynamic Performances of HSK Spindle/Toolholder Interface
Authors: Zhang Song , Ai Xing
Published: March 2010

In the present paper, a dynamic modeling approach is presented to determine the contact stiffness and structural damping between the spindle and the toolholder; and then, the spindle and the toolholder are coupled by some springs and dampers. Finally, the dynamic performances of the HSK-A63 spindle/toolholder interface are analyzed by means of finite element method (FEM). From the simulated results, it can be seen that the natural frequencies of the first two modes increase with the increase of the rotational speed, which make the HSK spindle/toolholder interface appear good dynamic performances and be suitable for high-speed machining.
Dynamic Collision Detection with Optimum Discrete Interval
Authors: Li Jian Guang , Xie Gao Wei , Yao Ying Xue , Xia Ping Jun
Published: March 2010

An improved algorithm, dynamic collision detection with optimum discrete interval is presented to improve the efficiency of dynamic collision detection. The algorithm based on the minimum distance between two objects with relative movement to determine the next discrete position, on which collision or interference is free. The method using the minimum distance as discrete interval to determine the next interference-free position makes each interval longest under the constraint of safety so that the reliability between the moving object-pair is ensured while the efficiency is improved. The practical demonstration has proved that the improved algorithm is capable of high performance than that of the collision detection method with even discrete interval. This algorithm has been successfully used in a verification system of inspection process by secondary development of Pro/Engineer.
Preparation and Evaluation of Hydrophilic Fixed Abrasive Pad
Authors: Zhu Yong Wei , Li Jun , Wang Jun , Lin Kui
Published: March 2010

The swelling ratio and the pencil hardness of pad were introduced to evaluate the properties of hydrophilic fixed abrasive (FA) pad. The effect of pad composition on its swelling ratio and pencil hardness was studied. Results show that the swelling ratio increases with the rise of content of Trimethylopropane Triacrylate (TMPTA) and Urethane Acrylate (PUA) and the pad gets harder while there is more TMPTA and less PUA. Results also show that a low swelling ratio corresponds to a high material removal rate (MRR), and a low wet pencil hardness to a low surface roughness in each group.
Research on Virtual Material Removal Model in CNC Machining Simulation Based on Adaptive Dynamic Tri-Prism Algorithm
Authors: Wang Wen Jin , Wang Tai Yong , Fan Sheng Bo , Zhang Zhi Qiang
Published: March 2010

In this paper, based on the octree partition, bounding boxes and triangulated surface model, we developed a new virtual material removal method for machining of 3D complex surfaces. In this method a new tri-prism space partition algorithm based on octree and triangulated surface model is applied to partition the 3D complex surfaces. Traditional triangular-faced algorithm is used in 3-axis machining simulation, which is computationally expensive and memory demanding. In contrast, this paper presents a virtual material removal model using the dynamic tri-prism space decomposition algorithm (i) to represent 3D complex objects, (ii) to reduce the computation complexity, and (iii) to accelerate the model updating procedures in a graphic simulation process. Based on mathematical model of virtual material removal, the 3D model of virtual CNC machining process was developed.
Data Management System for Complex Mechanical Product in Collaborative Simulation Environment
Authors: He Zhao Xia , Liu Geng , Liu Lan , Han Bing
Published: March 2010

In order to implement collaborative work in enterprises, it is important to exchange and share data during product design process. According to the characteristics and types of simulation data for mechanical properties analysis, an effective data management method is presented. Based on the functional framework of collaborative simulation environment, a new database system has been designed by combining relational database and content repository. The content repository for simulation data has been established and designed by user-defined node type whose model is a simple hierarchy. In this repository, simulation metadata have been stored as node properties. Furthermore, simulation data files can be stored in node which facilitates the upload and download of files. In the mean while, simulation flow data can be stored in relational database. An engineering application is employed to demonstrate the feasibility and practicability of the data management system.
Development of Whisker Toughening Ceramic Cutting Tool Composite by In Situ Synthesis Technology
Authors: Liu Bing Qiang , Huang Chuan Zhen , Liu Han Lian , Chong Xue Wen
Published: March 2010

While whisker toughening ceramic cutting tool composites have excellent mechanical properties at either room or high temperature, the development of them is often limited by some difficulties in the fabrication and application. Here a TiC whisker toughening Al2O3 ceramic cutting tool composite is developed by in situ synthesis technology. Experimental results show the flexure strength, fracture toughness and Vickers hardness of the composite can achieve to 855.7MPa, 7.63 MPa•m1/2 and 19.5GPa, respectively. Being different to that of conventional whisker toughening ceramic composites, the toughness of the composite is dominated by the chemical interface bonding between TiC and Al2O3, which increases with increasing sintering temperature, and the sliding resistance is suggested to be due to the physical absorption and mechanical meshing between the two debonded surfaces.
Simulation of Gas Flow Field in HFCVD System for CVD Diamond Growth
Authors: Lin Huan Qing , Lu Wen Zhuang , Zuo Dun Wen , Yang Chun , Xu Feng
Published: March 2010

The thermal blockage and thermal round flow in HFCVD system for CVD diamond growth will lead to un-stability of product quality. Finite element method has been used to simulate the gas flow field around the cutting tool substrate within a HFCVD diamond reactor. Experiments have been done to prove the simulation results. Excellent agreement between simulation and experiment was obtained by depositing of CVD diamond coated cutting tool. The thermal blockage and thermal round flow in HFCVD system decrease by using a hollow substrate holder. High quality CVD diamond coating can be obtained using a hollow substrate holder.
Study on Strengthening Mechanism of Microscale Laser Shock Peening
Authors: Fan Yu Jie , Zhou Jian Zhong , Huang Shu , Wang Min , Zhu Yin Bo , Hu Ling Ling , Zhao Jian Fei
Published: March 2010

Microscale laser shock peening (μLSP) is a novel surface treating technology which oriented to microscale metal components in MEMS. Beneficial compressive residual stress is induced at the shocked region to improve the performance of microstructure based on wave-solid interactions. In this paper, the basic principle of μLSP and mechanism of wave-solid coupling were introduced, the influence factors on strengthening effects, such as micro-size effect, anisotropy, dislocation, stacking fault, grain boundary and surface energy were discussed from the microscopic point of view, the results provide theoretical guidance for further study.
Finite Element Modeling and Tansfer Function Prediction of Ball-Screw Drive System
Authors: Lu Li Hua , Liang Ying Chun , Yu Fu Li , Su Bao Ku
Published: March 2010

The closed-loop performance of a ball-screw drive is usually limited by a resonance in which the carriage oscillates in the direction of motion as the screw undergoes longitudinal and torsional deformation. By means of the finite element method (FEM), a model of ball-screw system dynamics is presented by taking into account the distributed inertia of the screw and the compliance and damping of thrust bearings, nut and coupling. Transmission ratio is modeled using DOFs (degree of freedoms) constraint equation. The model is found to accurately predict the transfer function from motor torque to carriage position. Comparing the predicted responses with experiments performed on a pair of ball-screw drives, the resonance frequency is misestimated as much as 5% in the worst case.
AHP Based SWOT Analysis for Green Manufacturing Strategy Selection
Authors: Li Cong Bo , Liu Fei , Wang Qi Feng , Li Cai Zhen
Published: March 2010

Selecting an appropriate strategy is very important to the Green Manufacturing implementation. Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis is a commonly used tool for strategic management. Here SWOT analysis in combination with AHP is used to the selection of GM strategy. The strategic factors system of SWOT analysis for GM strategy is constructed by analyzing internal and external environments of the enterprise. Then AHP based SWOT analysis is introduced in detail. A case study demonstrates the application of AHP based SWOT analysis in GM strategy selection and shows its feasibility and validity.
Experimental Research on Cutting of Silicon with Fixed Diamond Wire Saw
Authors: Zhao Li Gang , Zuo Dun Wen , Sun Yu Li , Wang Min
Published: March 2010

The experimental research on silicon was reported in this paper. The surface roughness under the different workpiece feed speed and linear velocity of the wire saws is studied mainly in this experiment. The effects of the workpiece feed Vs and the linear velocity of the wire saws Vw were analyzed.
Predictive Tool Life Model in Ti6Al4V High Speed Milling and Cutting Parameter Optimization
Authors: Wang Xiao Qin , Ai Xing , Zhao Jun
Published: March 2010

Ti6Al4V is a difficult to machine alloy with low cutting efficiency and server tool wear. A series of orthogonal milling tests with coated and uncoated carbide insert was carried out. The tool life predictive models based on orthogonal experiment were developed. Finally, the cutting parameters for both tools in Ti6Al4V dry milling were optimized based on tool life-efficiency contour analysis.
Grain-Workpiece Interaction Study of Grinding Process through Single Grain Cutting Simulation
Authors: Yan Lan , Zhou Zhi Xiong , Jiang Feng , Li X.K. , Rong Yi Ming
Published: March 2010

Grinding process can be considered as micro-cutting processes with the irregular abrasive grains on the surface of grinding wheel. The grain-workpiece interface directly forms the workpiece surface. Therefore, the study of the grain-workpiece interaction through micro-cutting analysis becomes necessary. But the experiments for single grain cutting are difficult to perform. Aimed at this problem, single grain cutting simulations of AISI D2 steel with a wide range of cutting parameters have been carried out with AdvantEdgeTM in this study. The effect of cutting parameters on cutting force, specific cutting force, material removal rate and critical depth of cut has been analyzed.
Automatic Positioning and Tool Path Planning of Ultra-Large-Scale Components
Authors: Wu Jia Feng , Gao Dong , Yao Ying Xue
Published: March 2010

A method for machining huge workpiece is proposed using coordinate transformation theory. The mathematical model of positioning is derived with nonlinear least square method and solved by iterative algorithm which is given by tangent plane iterative method. Then, initially generated tool paths are modified and optimized. The experiment demonstrates that this method for machining ultra-large-scale workpiece is feasible and correct. The proposed automatic positioning algorithm and tool path optimization method can be used to machine huge workpiece to improve accuracy and reduce cost.
Fatigue Life Simulation on Forestay Bar of Aircraft Landing Gear
Authors: Li Xiang Feng , Chen Jin Dong , Zuo Dun Wen
Published: March 2010

Firstly, taking the stability of the forestay bar as the restraint, the section area of the forestay bar was optimized from 1800 mm2 to 1178 mm2, with reduced weight of 16.1%. Secondly, the equivalent load of the forestay bar was obtained by using dynamics simulation software. Finally, the stress field and the fatigue life of the forestay bar were simulated. The results show that stress of the forestay bar with 929MPa can meet the requirement for its material strength, and fatigue life of 51200 times also satisfies the request of the nose landing gear. That is, material property of the forestay bar is utilized more than before, and its weight decreased successfully.
Modeling of Polishing Pad Wear in Chemical Mechanical Polishing
Authors: Li Mao , Zhu Yong Wei , Li Jun , Lin Kui
Published: March 2010

The polishing pad’s wear influences the surface accuracy of the polished wafer. A new polishing pad wear model is established using the idea of Finite Element Analysis (FEA) and the effect of polishing parameters on the wear of polishing pad is discussed.