bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Intelligent Deep Drawing Technology of Sheet Metal
Authors: Ma Rui , Zhao Jun , Peng Xiao Ting
Published: March 2010

The intelligent sheet metal forming is a new technology. In this paper, take cone-shaped wall pieces and cone-box shaped part as an example , the key technologies in real-time monitoring, real-time identifying, real-time forecasting and real-time controlling are studied, which gradually is the theoretical basis for intelligent deep drawing control. The results can be more satisfactory when the artificial neural network is used in real-time identifying and real-time forecasting, when in the blank hold force control phase load curve is along critical rupture curve. In the course of this study the intelligent deep drawing experimental system is developed, in which the better identifying forecasting accuracy is showed. The research laid that the intelligent control method for deep drawing of a simple shape parts will be the successful sample of complex parts.
Effects of Lanthanum on Fe-25Cr Alloys under Cyclic Oxidation
Authors: Othman Norinsan Kamil , Jalar A. , Othman N. , Young David J.
Published: March 2010

Fe-Cr binary model alloys (Cr: 25 wt %) with additions of 0.09 wt% lanthanum were subjected to cyclic oxidation experiments at 700oC. All model alloys were exposed in five different gases; Ar-20O2, Ar-20O2-5H2O, Ar-5O2-20H2O, Ar-10H2-5H2O (pO2 = 3.64 x 10-22 atm) and Ar-10H2-20H2O (pO2 = 7.37 x 10-21 atm) all in volume %. Very low weight gains were observed in all gases of Fe-25Cr-0.09La. However, breakaway oxidation occurred on La-free alloy experienced increased weight gain in Ar-5O2-20H2O due to formation of iron-rich oxide. The addition of La (<0.1 wt%) to the Fe25Cr retarded the growth of iron-rich oxide in Ar-5O2-20H2O.
Research on Damping and Vibration Characteristic of the Large and Precision NC Rotary Table
Authors: Yu Chun Jian , Huang Xiao Diao , Fang Cheng Gang , Dai Ke Fang
Published: March 2010

According to the current situation of acicular chip and high-frequency chattering of the NC rotary table while gear milling, rigidity and damping performances of the table were analyzed and the damping program of Coulomb friction was bring up. Online test of the gear milling cutting force can be used to establish dynamic model of circumferential vibration of the table with Coulomb friction. Then mechanism of restraining gear cutting chatter by damping of Coulomb friction and acicular chip generating mechanism were exposed. Furthermore, relationship between backlash and rotary rigidity of the table was also analyzed. A kind of floating apparatus with friction damping was designed to optimize circumferential damping of the table by adjusting Coulomb friction force, which reduces the influence of high-frequency chattering on gear milling. As a result, efficiency of gear milling was increased 1.5 times and the noise was reduced from 105dB to 91dB.
The Simple Model of the Oil Film Thickness between Piston Ring and Cylinder
Authors: Liu De Liang , Lu Hui Biao , Sun C.G.
Published: March 2010

Piston ring-cylinder is one of the most important friction pair of internal combustion engine，the lubricating state between them has decided internal combustion engine lubrication quality. So the theoretical research to the lubricating characteristics of the piston-ring group, especially the calculation of the lubricating oil film thickness is very important. The oil film thickness between piston-ring and cylinder is studied by calculation method. The calculation program is developed with average Reynolds equation taken the surface topography, viscosity-temperature effect, viscosity-pressure effect, extrusion effect and other factors into account. The position of oil outlet point is preinstalled, the full lubrication is assumed, and the Reynolds equation is solved by full pivot element gausses elimination approach, so the iterative course and calculation workload are reduced, and a great lot of the calculating time is saved, the oil film thickness of full period can be more accurately predicted by the ordinary PC within 30 minutes, which can supply quick effective evidence for next calculation and analysis.
Preparation and Characterization of Electroless Co-Ni Coated ZrO2 Powder for Microwave Absorbing
Authors: Jiang Jing Hua , Lu Fu Min , Ma Ai Bin , Zuo Jin Zong , Gao Yi
Published: March 2010

Co-Ni coated ZrO2 composite powder was prepared by an optimized ultrasonic electroless plating process to obtain good microwave absorption properties in GHz region. Aggradation mechanism of electroless Co-Ni alloy was analyzed and the principal influencing factors on the depositing rate were investigated by weighting-in-powder. The metallized powder was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and vector network analyzer. Results showed that ultrafine ZrO2 powder pretreated with sensitization and activation were homogeneously deposited with Co-Ni coating at 358K and pH value of 9, immerged in the optimal plating bath using NaH2PO2 as reductant. The Co-Ni coating deposited in the alkaline plating bath had the depositing rate of above 6µm/h and the average weight ratio of 5.5 for Co/Ni. The new metallized powder was endowed high microwave absorbing properties; the maximum reflection loss reaches to -23dB at the frequency of 9.40 GHz.
A New Springback Compensation Method for Sheet Metal Bending Based on Curvature Correction
Authors: Liao Juan , Zhou Chi , Ruan Feng , Zhu Yin
Published: March 2010

The dimensional inaccuracy caused by springback is a major problem for most stamping applications. One of the most promising ways to solve this problem is to compensate it by means of appropriate tool shape modifications. In this paper, a new springback compensation method is introduced. A coefficient of curvature correction, which reflects the deviation of the experiment data and the analytical calculation data, is also proposed to redesign the tooling shape. This method was applied to a two-dimensional wavy-shaped part forming case for verification. The experiment results demonstrated that this method is efficient.
Study on Vehicle Wheel Automatic Recognition Based on the Manufacturing
Authors: Li Chang Chun , Zhang Tian Hou , Wang Shi Feng
Published: March 2010

The paper discusses the major manufacturing processes of vehicle wheels and the current load-unload situation, analyses the structural shape of vehicle wheels, and designs the vehicle wheel gripper. Also the paper studies the image acquisition, image processing and automatic recognition based on the vehicle wheel manufacturing.
Remanufacturing of High Temperature Ball Valve by Surface Engineering Technology
Authors: Huang X.L. , Liu Lin , Gu Bo Qin , Shao Chun Lei , Zhou Jian Feng
Published: March 2010

Four kinds of coating materials and two kinds of brush plating materials were screened and sprayed on the surface of valve ball by plasma spraying technology and brush plated on the surface of valve seat by electrical brush technology, respectively. The wear resistance of the sealing pairs and the properties of the plasma sprayed coatings were tested. The results indicate that the sealing pair composed of the valve ball with the plasma sprayed coating of Al2O3-TiO2 and the valve seat with the brush plating layer of nickel tungsten has best combination property. The gap of the sealing pair at room temperature and the leakage rate at elevated temperature of the high temperature ball valve were obtained by FEM method and analysis method, respectively. Therefore, the open and close torque of the high temperature ball valve was determined. According to the results of the research, the failed ball valve was remanufactured, and the performance inspection was also conducted. The remanufactured ball valve has much longer service life than the original one and its sealing behavior was also improved significantly.
Pulse Electrodepositon of Ni-W-P-CeO2-SiO2 Composite Coatings
Authors: Xu Rui Dong , Wang Jun Li , Zhang Yu Zhi , Guo Zhong Cheng
Published: March 2010

Square-wave pulse current was used to electrodeposit Ni-W-P-CeO2-SiO2 composite coatings. The influence of pulse on-times, off-times and peak current densities on properties of the composite coatings was researched. The microhardness, chemical compositions and microstructures were evaluated by EDX, SEM and microhardness tester. The results show that the composite coatings possessed higher microhardness and fine-grained structure. The crystal sizes of the composite coatings were found initially to decrease with the rise of pulse on-times before it started to increase with further increasing pulse on-times. Decreasing pulse off-times or increasing pulse peak current densities resulted in considerable refinement of crystal sizes.
Fabrication of Bionic Silicon Surfaces with Lotus Effect and their Micro Tribological Performance
Authors: Fan Xi Qiu
Published: March 2010

With the miniature of micro-electromechanical systems (MEMS), surface effect is substantially increased, and the resulting friction, abrasion and stiction are becoming bottlenecks of the development of MEMS industry. In this paper, firstly, the feature size and topography on lotus leaf surfaces is investigated, as well as the mechanism of lotus effect applied in MEMS to reduce friction and prevent stiction is analyzed; secondly, two approaches of fabricating bionic silicon surfaces with lotus effect are proposed; finally, test results on the micro tribological performance of the mimicked silicon surfaces are presented, which demonstrates that to mimic lotus effect on silicon surfaces is a novel approach to prevent stiction and reduce friction . However, the effectiveness of stiction prevention and friction reduction is related to the size and shape of the textured structures.
Influence of Hot Working Conditions on Mechanical Properties and Microstructures at Weld Zone of the Ti3Al /TC4 Dual Alloy
Authors: Yao Ze Kun , Qin Chun , Guo Hong Zhen , Cao Jing Xia
Published: March 2010

The influences of different hot working conditions on the microstructures and mechanical properties at weld zone of the Ti3Al/TC4 dual alloy have been investigated. The experimental results show that forging and heat treatment has significant influence on room temperature tensile strength (RTTS for short) of the weld zone. The influence of forging strain and temperature on its elongation at temperature 500°C is also conspicuous. The results of intuitional and variance analysis show that affecting factors of its RTTS are heat treatment, forging strain, forge temperature and condition of billet in sequence. The affecting factors of its room temperature (RT for short) ductility and the tensile strength (TS for short) at temperature 500 °C are forging strain, forge temperature, heat treatment and condition of billet. Good comprehensive properties are obtained under optimal conditions: forging at 1020°C, annealing at 700°C for 12 hours, air cooled, about 40% strain and as-rolled billet. The microstructures of the weld zone worked according as those conditions are uniform and the grain size is also fine.
Influence of Laser Surface Texturing Distribution Patterns on the Hydrodynamic Lubrication
Authors: Liu Hong Bin , Han Hong Biao , Xue Yu Jun , Li Ji Shun
Published: March 2010

Laser Surface Texturing (LST) is an advanced method of surface micro-texturing technology. The aim of this paper is to investigate the influence of laser surface texturing distribution patterns on lubricant characteristics for laser texturing surfaces against cylindrical under conditions of film lubrication. The laser texturing surfaces are processed with power levels under YAG laser. Under conditions of constant depth and area coverage ratio of LST,patterns of the texture distribution and the sliding orientation relative to the texture were systematically varied. The experimental results suggested that 20° circumferential interval can increase the load-carrying ability of lubricating film.
Finite Element Analysis of the Temperature Field and Strain Field of Coating Rod in Friction Surfacing
Authors: Liu Xue Mei , Zou Zeng Da , Wang Xin Hong , Qu Shi Yao
Published: March 2010

In friction surfacing process, the temperature field and strain field, especially of coating rod, is considered an important element in analyzing the process’ mechanism and choosing the key process parameters properly. In this paper, the finite element method was employed to simulate the coupling of 3-D temperature field and deformation field of coating rod during friction surfacing. The simulation results show that at the preliminary preheating period, the isotherm goes down at the center part, and the temperature field presents “M” along the radial direction. The temperature increasing rate at the friction interface is higher at first, and then become lower, once the friction system becomes quasi-steady, the temperature here will be stable approximately. The largest effective strain occurs near the center of bottom circle. The simulation results are close to the experimental results, thus builds a basis for analyzing the process’s mechanism, allows for theoretical guidance for analyzing feasibility and helps optimize key parameters.
A Statistical Model for the Joint Distribution of Droplet Size and Charge Density in an Electrostatic Spray
Authors: Zhang Jun , Reeks Michael W.
Published: March 2010

A theoretical model to predict the joint distribution of droplet size and charge density for an electrostatic spray is described based on the maximum entropy method. From known values of the electrostatic spray parameters, the model is used to evaluate the joint distribution of droplet size and charge density for a cone-jet mode electrostatic spray. The predicted results of present model show that it has generally a relatively narrow distribution for both droplet and charge density in a cone-jet mode. Comparatively, the droplet size distribution is narrower than that of the charge density. In addition the two distributions are significantly different in shape. The droplet size distribution is nearly symmetric about its peak position, whilst the left side of the charge density distribution curve is noticeably steeper than the right side. The results are also compared with existing experimental data with agreement considering the uncertainties in the data.
Anti-Wear Property of Self-Repairing Mineral Particles as Grease Lubricant Additives on the Metal Friction Pairs
Authors: Chen Wen Gang , Gao Yu Zhou , Zhang Hui Chen , Tan Ze Fei
Published: March 2010

The characteristics of the 1045 steel pairs using serpentine particles as grease lubricant additive were investigated by an AMSLER friction and wear tester. The surface topographies and composition of the worn surface of 1045 steel rings were identified by SEM and XPS. The results show that the additives can form a self-repairing film on the worn metal surface. It can reduce the abrasion of the friction pairs significantly. The main elemental compositions of the film are Fe, O, Si, C and Mg, which indicates that the additives directly take part in the formation of the self-repairing film.
Fabrication of n-SiO2 Reinforced Al2O3 Composite Coatings on 7A52 Aluminium Alloy by Micro-Arc Oxidation
Authors: Ma Shi Ning , Suo Xiang Bo , Qiu Ji
Published: March 2010

Micro-arc oxidation (MAO) is an effective approach to improve the properties of aluminium and its alloys by forming ceramic coatings on the surface. However, the oxide layers often have a porous surface structure, which limits their mechanical properties. In order to enhance the properties of the layers produced by micro-arc oxidation, SiO2 nanoparticles reinforced Al2O3 composite coatings were produced on 7A52 aluminium alloy by adding SiO2 nanoparticles into the electrolyte. With the addition of SiO2 nanoparticles in the electrolyte, the formation rate of Al2O3 coating enhanced considerably and the current density through the sample surface became much higher than that without SiO2 at the same voltage. The coatings were investigated with X-ray fluorescence spectrometry (XRF), Scanning electron microscopy (SEM), Vickers hardness test, and reciprocating friction and wear test. Compared with the Al2O3 coatings without SiO2 nanoparticles, the n-SiO2 reinforced Al2O3 composite coatings are much denser and harder, and the wear resistance is also improved significantly. The improvement can be attributed to the enhancement of the surface structure and morphology of the n- SiO2 reinforced Al2O3 composite coatings.
Influence of Ultrasonic Peening on Wear Resistance of U70 Rails
Authors: Chen Zhao Xia , He Bo Lin
Published: March 2010

The surface of U70 rails was treated by ultrasonic peening method. Keeping the electric current 1.5 A, the amplitude 24 µm and the frequency 10000 HZ during the treatment, the peening duration was 10 min, 20 min, 40 min and 60 min respectively. The wear property, wear appearance, and structural appearance of specimens have been studied by M-2000 wear tester and 6360LA scanning electron microscope. Results show that ultrasonic peening treatment can significantly improve the wear resistance of U70 rails, and the longer the peening duration, the stronger the wear resistance. The wear mass loss of the specimen with 60 min treatment is only 27 % of the one untreated. The reason is that ultrasonic peening can form plastic deformation zones. The depth of plastic deformation zones increases with the peening duration. The depth of plastic deformation zones of the specimen with 60 min treatment is nearly 100 µm. Longer peening duration means severer plastic deformation. In the plastic deformation zone, ferrite is refined to smaller grains so that the matrix is strengthened.
Surface Hardening of Spot-Welding Copper Alloy Electrode for Zinc Coated Steel
Authors: Luo Cheng , Xiong Xiang , Dong Shi Jie
Published: March 2010

Zinc coated steel, spot-welding electrode, titanium carbide, titanium diboride, coating.
Abstract: TiC and TiB2/Ni were coated on the surface of cupper alloy electrodes used for spot-welding of zinc coated steel sheets by electrospark deposition to improve its lifespan. The coatings structure and phase compositions were characterized by SEM and XRD, and their life spans were examined by spot-welding test. The results indicate the major phases of the coatings are TiC and TiB2 respectively, and copper diffuses from the substrate into the top surface of the coatings during electrosparking, forming an atomic bonding between the coatings and the substrate. The electrodes are hardened by coatings. Though cracks exist, the coatings can segregate the steel sheets and the substrate and prevent zinc in the surface of steel sheets and copper in the substrate from alloying. The coatings also reduce the deformation of the electrode during spot-welding. As a result, the spot-welding lives of TiC and TiB2/Ni coated electrodes are prolonged significantly by one and two times respectively.
The Influence of Laser Hardening on the Microstructure and Wear Resistance of Disk Opener
Authors: Sun Hao , Ling Gang , Li Hong Wen , Su Yan Bo , Xiong Shao Ping , Yao Hai Rong
Published: March 2010

The microstructure and properties of hardened layer of 45 steel disk opener with a variety of parameters of HLD1001.5 solid-state laser were studied by SEM, Rockwell hardness tester and wear tester. The results showed that under the conditions of the laser power from 400W to 600W, the hardened layer is composed of melted zone, phase transformation zone and heat affected zone, and the hardness is up to 58.5-61HRC, and the disk openers have excellent wear resistance after the laser hardening, which is best in the disk opener with the treatment of laser power 500W.
Microstructure and Wear Properties of Laser Clad TiN/Co-Based Composite Coating
Authors: Zhou Jun , Xie Fa Qin , Li Yong Quan , Wu Xiang Qing
Published: March 2010

Co-based composite coatings reinforced by TiN particles were fabricated on Ni-based superalloy substrate by using a 5 kW CO2 laser. The microstructures and phases constitution of the composite coating were studied by means of optical microscope (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The microhardness and wear resistance of the coating were also examined. The results showed that the composite coating was mainly composed of γ-Co, TiN, TiC, (Cr, W)23C6 and Co3Ti. And different solidification morphologies, such as planar, cellular and dendrite, were obtained. Structural transformations were attributed to the temperature gradient and solidification rate in metal-melting region. It was found that the microhardness of the composite coating was enhanced prominently as compared to the substrate region, which should be due to the undissolved TiN and other new complicated phase. Friction and wear tests without lubrication showed that the addition of TiN particles into Co-based coating can improve its wear resistance significantly without evidently increasing the friction coefficient of coating.
Microstructure and Reciprocating Sliding Tribological Performance of Micro-Arc Oxidation Coating Prepared on Al-Si Alloy
Authors: Lin Xiu Zhou , Zhu Min Hao , Cai Zhen Bing , Zheng J.F. , Peng Jin Fang
Published: March 2010

Micro-arc oxidation coatings were prepared on Al-Si alloys surface by using a self-made micro-arc oxidation equipment. Its characterizations were systematically detected by Vickers hardness tester, profilometer, scanning electron microscope (SEM), energy dispersive X-ray spectrum (EDX), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). Reciprocating sliding tribological tests without lubricant of the micro-arc oxidation coating and its substrate alloy have been carried out under normal load of 5 N and displacement amplitudes of 2 mm. Dynamic analyses in combination with microscopic examinations were performed in detail through optical microscope (OM), SEM and EDX. The experimental results indicated that the MAO coating, with rough surface, high hardness and typical porous ceramic structure, is mainly consist of Al2O3, SiO2 and Al2SiO5 phases. The elementary substance Si and Al are not presented nearly on surface of coatings since the alloy is oxidated adequately during the micro arc oxidation process. Three stages can be observed in the friction coefficient curves both for the MAO coating and its substrate. The COF of the substrate was very low in initial stage, then a rapid ascend to a higher level and fluctuated in a larger range. But for the MAO coating, since its higher hardness and rough surface, the COF was higher than its substrate in initial stage. After a gradually ascent stage, the COF reached a steady state with a small range fluctuation and higher values. The wear mechanism for Al-Si alloy was main adhesive wear, abrasive wear, delamination and slight oxidative wear. After the micro-arc oxidation, the wear resistance of Al-Si alloy was greatly improved, and the wear mechanism of the MAO coating was the combination of delamination, abrasive wear, slight oxidative wear and some material transferred from the ball specimen.
Erosion Wear Behavior of Coatings with Growth Defects Produced by Ion Beam Enhanced Pulsed Filtered Vacuum Arc Deposition
Authors: Wu Feng Fang , Deng Jian Xin , Yan Pei , Song Wen Long
Published: March 2010

The erosion wear behavior of TiN coatings with growth defects was studied. The TiN coatings were produced on a hard metal by ion beam enhanced pulsed filtered vacuum cathode arc deposition. The erosion wear was tested with a gas blast apparatus. In the test, TiN coatings were impacted at an impingement angle of 90° by angular SiC solid particles with an average diameter of 124um. The maximum depth of the erosion scar measured by the optical profiler was used to evaluate the erosion wear loss of the coatings. The coatings proved to have much lower erosion rate than that of the substrate material and consequently, the erosion rate increased significantly to the high level of the hard metal substrate after the coatings were penetrated. The failure mechanism was revealed by examining the surface morphologies of the coatings before and after the erosion test. The erosive wear of the TiN coatings with growth defects behaved as typical brittle materials. The damage mechanism of the coatings with growth defects was described.
Rotational Fretting Wear of Ion Nitrided Medium Carbon Steel
Authors: Luo J. , Wang Y.D. , Song C. , Mo J.L. , Zhu Min Hao
Published: March 2010

The nitrided layer on the surface of LZ50 (0.50% C) carbon steel was prepared by ion nitriding technique and its characterizations were detected by using Vickers hardness tester, profilometer, scanning electric microscope (SEM), optical microscope (OM) and X-ray diffraction (XRD). Rotational fretting is one of basic running modes in contact configuration of ball-on-flat, to which was paid little attention. The rotational fretting wear behaviors of the nitrided layer and its substrate steel were comparatively studied in dry condition under varied angular displacement amplitudes (θ) in range of 0.125º-1º, imposed normal load (Fn) of 20 N and a constant rotational speed of 0.2º/s. The experimental results showed that the nitrided layer presented rough and porous surface and high hardness was mainly consist of ε-Fe2-3N and γ׳-Fe4N phases. Compared with the substrate steel, the nitrided layer had a significant effect on reducing the friction coefficient and improving the fretting wear resistance, though the nitrided layer almost didn’t change the fretting running regimes of the substrate steel. In the partial slip regime, lower friction coefficients and slight damage appeared for the nitrided layer due to the coordination of elastic deformation of contact zones. In the slip regime, the friction coefficient of the nitrided layer was lower than that of the substrate in the initial stage as a result of the preventing plastic deformation by its high hardness surface. The rotational fretting wear mechanism of the nitrided layer in the slip regime was mainly identified as abrasive wear, oxidative wear and delamination. As a result, the nitrided layer presented a better capability for alleviating rotational fretting wear.
Microstructure Characteristic of Laser Cladding Ceramic Layer on High Cr Cast Steel Surface
Authors: He Yuan Shan , Li Yi Shan , Huang Wei Ling , Wang Yong
Published: March 2010

In this experiment Al2O3 gradient ceramics coating is cladded on the high Cr cast steel by 5kW crosscurrent CO2 laser with Ni-based alloy which is used as transitive metal. The microstructure is analyzed with optics microstructure analyzer and the crystal grain characteristic is studied. The microstructure of the laser cladding layer have the plane crystal zone, the butcher crystal zone, the dendrite zone and the surface equiaxed grain zone that grow along the substrate. The microstructure of the coating compared with the substrate is extremely tiny, and the microstructure of the multi-layer cladding presents stratification. The phase composition of the clad coating is composed primarily of NiAl intermetallic compound, but also includes γ-FeNi and a little Ni3Al compound. In the coating the Al2O3 pellet that some present the unit crystal form, and some little accumulate in together, plays the dissemination strengthening role in the coating material. The massive twin crystals and the dislocation staffing are presented in the clad coating.
Growth Behaviour of ZnO on Si (100) and Platinum Coated Glass Substrate from Aqueous Solution
Authors: Bakar M.A. , Hamid Muhammad Azmi Abd , Jalar A.
Published: March 2010

Zinc oxide nanorods were grown on Si (100) and Platinum coated glass substrate by the aqueous chemical growth (ACG) in aqueous solution that contained zinc nitrate hexahydrate (Zn(NO3)2•6H20) and hexamethylenetetramine (C6H12N4). The obtained ZnO nanorods are uniformly distributed on the Platinum coated glass substrate surface from 1.5 h to 3 h growth time. Branched hexagonal rods were also found growth on these uniform nanorods. Branched hexagonal rods were found on Si (100) from 2 h to 3 h growth time. A small number of flower-like structures compared to the majority oval type structure suggest that secondary nucleation had occurred during the process of growth. All of the high intensity peaks, including the strong (101) peak, are assigned to wurtzite ZnO hexagonal indicating that the product is pure ZnO. The results found in this study revealed that the type substrate plays a role in determining the surface morphology of ZnO growth.
Synthesis of TiO2/Polymer Composite Microspheres Using Functional Porous Polymer Particle as Substrate
Authors: Li Sen , Wang Kuan , Song Chun Lian , Cheng Jiang , Yang Zhuo Ru
Published: March 2010

This study described a different nano-titania(TiO2)/polymer composite where TiO2 were uniformly deposited on the porous poly(styrene-divinyl benzene-co-maletic anhydride)　[poly(st-DVB-co-MAH)] microspheres. The morphology of the composite microspheres was analyzed by scanning electron microscope and X-ray diffraction. Both the diameter of the pore and the MAH functional groups played a crucial role in controlling the structure of TiO2 shell. The rutile nanoparticles were incorporated evenly onto the surface of the porous microspheres when microspheres with pore diameter of about 146.8 nm and with surface 30 wt% functional groups (MAH) were used as substrate.
Numerical Simulation on the Effect of Process Parameters for Incremental Sheet Forming
Authors: Qin Qin , Wu Di Ping , Li Mi , Zang Yong
Published: March 2010

Incremental sheet forming (ISF), based on the ‘layered manufacturing’ principle of rapid prototype manufacturing technology, is an innovative and highly flexible technology for forming complex shaped parts without the need for costly dies. This paper presents a numerical investigation on the influence of forming process parameters by modeling the forming process. ANSYS/LS-DYNA has been used for the simulation. The results of study show that small vertical step size can improve the accuracy of the forming. Moreover, large forming angle can increase plastic strain and the four screwdown point optimization paths is an effective method to increase the accuracy of the formed sheet.
Characteristics and Elastic Modulus Evaluation of Pd-Nafion Ionic Polymer-Metal Composites
Authors: Zhu Zi Cai , Chen Hua Ling , Li Bo , Wang Yong Quan
Published: March 2010

Ionic polymer-metal composites (IPMCs) show great potential in a large variety of engineering fields as actuator materials. They mainly consist of electrodes and ionic polymer as the substrate material. Many metal materials can be used as the electrode material of IPMCs. In this paper palladium was adopted to get a compromise between the cost and the stability, and Pd-Nafion IPMC was fabricated by chemical plating as test sample. Preliminary experiments were accomplished with satisfactory result using a suit of self-made measurement setup. The results showed that palladium was a good electrode material. Although some previous work has investigated on the elastic modulus of IPMCs by tensile test, a simple method based on the cantilever beam theory to estimate the modulus is still proposed here, which does not need a tensile testing machine. By the method we got that the elastic modulus of the sample is 362.35MPa.
Effects of Technological Parameters on Microstructures of Semi-Solid Magnesium Matrix Composites
Authors: Hu Yong , Li Shu Zhen , He Bo Lin , Yan Hong
Published: March 2010

Mg2Si/AM60 composites were fabricated by in-situ synthesis and the effects of different stirring technological parameters on the microstructures of semi-solid magnesium matrix composites were investigated in this paper. The results indicated that there were Chinese script type Mg2Si particles in the microstructures by addition crystal Si to the magnesium alloys. The mechanical stirring was used to fabricate the semi-solid composites and the results showed that the higher the stirring temperature and speed are, the finer and more homogeneous the spherical grains would be. If the temperature is too high, the grains will be melted. With the increasing of stirring time, the grains become fine, well-distributed and round at first, then grow up.
The Study of Mechanical Properties of Structural Lightweight Concrete
Authors: Cui Hong Zhi , Xing Feng
Published: March 2010

Many investigations have been conducted on compressive strength of lightweight aggregate concretes (LWAC), but there are few experimental studies on the relationship between compressive strength, bond strength and elastic modulus of LWAC. In this paper, the specimens of twenty kinds of LWACs with different mix proportions were made. Properties of compressive strength, bond strength and modulus of elasticity of the LWACs were tested. Based on the testing resulting, equations for relationship between bond strength and compressive strength of the LWAC were established. For LWAC modulus of elasticity, the experimental results of this study can fit well with predicted equation of ACI 318
High Strain Rate Superplastic Deformation Behavior of TiNP/2014Al Composite
Authors: Hu Hui E , Zhen Liang
Published: March 2010

TiNP/2014Al composite was prepared by powder metallurgy method with a reinforcement volume fraction of 15%. High strain rate superplastic deformation behavior of the TiNP/2014Al composite was investigated by tensile tests conducted at 818 K with different strain rates range from 1.7×100 to 1.7×10-3 s-1, DSC, OM, TEM and SEM. It is shown that a maximum elongation of 351% is achieved at 818 K and 3.3×10-1 s-1. The curve of value can be divided into two stages with the variation of strain rate and the critical strain rate is 10-1 s-1. Plastic deformation of the TiNP/2014Al composite at 818 K and 3.3×10-1 s-1 is conducted at an almost constant maximum value of flow stress. High strain rate superplastic deformation mechanism of the TiNP/2014Al composite deformed at 818 K with the strain rate of 3.3×10-1 s-1 is grain boundary sliding accommodation mechanism plus liquid phase helper accommodation mechanism.
Experimental Investigation on Drop in Tensile Performance Index of Carbon Fiber Composite in Use
Authors: Wu Ya Ping , Shi Qi , Sun Bing Nan , Wang Yin Hui
Published: March 2010

To investigate the causations why the tensile performance index of carbon fiber composite in use is generally under that offered by the manufacturer, the tests on the tensile characteristics of the carbon fiber monolayer and those of the gumming carbon fiber monolayer were carried out in this paper. Based on the test results and mixed principle of the relation between strength of composite and each of the components, the influencing factors on the drop in tensile performance index of the carbon fiber composite in use were analyzed. It is concluded that all kinds of the defects could reduce the local strength of composite materials. Internal defects of the composite, possible load eccentricity in the test, size effect of the composite sample, and tensile properties of the resin may be the primary influencing factors.
Parametric Modeling Method for Composite Microstructure Virtual Testing
Authors: Wang Zhen Qing , Wang Xiao Qiang , Zhang Ji Feng , Zhou Song
Published: March 2010

A method of parametric modeling composite microstructure is proposed. It can be used for composite microstructure virtual testing and optimization procedure. Considering the fiber random distribution features of composite microstructure and the flaw distribution in the fibers, a three dimensional parametric model has been built in this paper. Then, the sizes of the composite representative volume element (RVE) generated by the method are determined by moving-window function method. These models are close to reality and can be used for further virtual testing. Finally, numerical experiment is presented by the secondary development of the finite element packages (ABAQUS) via Python language programming to verify the proposed method. The following conclusions are obtained: (i) fiber volume fraction of the composite structure model reaches 65% by the modeling method, which meets the majority engineering demands; (ii) stress distribution feature of RVE generated by using moving-window function method coincides with general prediction.
Effects of Surface Modification of SiC Nanoparticles and Preparation Process on Microstructures of SiCp/A6061 Alloy Matrix Composites
Authors: Li Xiao Dan , Zhai Yu Chun , Li Jian Zhong , Qiu Feng
Published: March 2010

SiC nanoparticles (40nm) reinforced metal matrix composites (MMCs) were made by a common stir casting technique in two different preparation processing routes. In the first route, the coated ceramic powder was prepared using electroless plating to coat SiC nanoparticles by Cu. In the second route, Cu and SiC nanoparticles were fully mixed by high energy ball milling, and then SiC nanoparticles were embedded in Cu to form a “jujube-cake” structure. In both cases the average particles size were 0.2μm. The SiC nanoparticles enhanced A6061 alloy matrix composites were made by stir casting, and as-cast microstructures were studied by means of optical microscopy (OM) and scanning electron microscopy (SEM). The results show that in the first route, the Cu off and the slagging reaction occurs to form a mixture at the upper part of the ingot by a vacuum melting and the ingot central also has a large number of pores, only the lower part of the ingot organization is uniform. The second route can make better uniform composites.
Copper-Based Electronic Materials Prepared by SPS and their Properties
Authors: Guo Zhong Quan , Geng Hao Ran , Sun Bao Chuan
Published: March 2010

Copper-based electrical contact materials were prepared by Spark Plasma Sintering (SPS) method and powder metallurgy with the addition of different proportions of rare earth (RE) element. It is found that SPS method greatly enhances the density, hardness and conductivity of the composite materials, thus improving their comprehensive properties. Compared with powder metallurgy, SPS boasts a shorter sintering time, smaller compression force and higher efficiency. RE has considerable influence on the comprehensive properties of copper-based electrical contact materials. When the content of RE lower than 0.1%, the comprehensive properties can be improved by increasing RE.
Simulation and Analysis on Microstructure Evolution of Large Generator Retaining Ring during Multi-Fire Forging
Authors: He Wen Wu , Liu Jian Sheng , Chen Hui Qin , Guo Hui Guang
Published: March 2010

In order to investigate microstructure evolution of Mn18Cr18N retaining ring during the multi-fire forging, a series of constitutive equations for dynamic recrystallization, static recrystallization, meta-dynamic recrystallization and grain growth were developed and implemented into a Deform FE simulator. The single-axial hot upsetting test has been performed to investigate the process of microstructure evolution and to show validity and effectiveness of the developed program. Then based on the modified boundary condition, hot forging process for 300MW retaining ring was put into effect. The results have displayed that the microstructure prediction tool was validated by comparing the simulated grain structure with that of the experiment and it could provide a reference to optimize forging processes in the production of retaining ring.
The Numerical Simulation of Co-Curing Process for AGS Plate
Authors: Huang Qi Zhong , Ren Ming Fa , Chen Hao Ran
Published: March 2010

This article demonstrates the co-curing process for AGS plate. Based on the phenomenological models of resin flow and cure kinetic, the variations of temperature, cure degree and pressure were illustrated during the process by a 2D FEA program. Some valuable results were obtained that the distribution of coupling fields could be more uniform with a proper cure cycle and mold, and the resin flow action would be completed in 6000s since the pressure was applied.
The Characteristics of Multilayer Thin Films Deposited with Metal Thin Films (Ag, Al, Cu)
Authors: Kim Dong Hun , Murakami Riichi , Kim Yun Hae , Moon Kyung Man , An Seung Jung , Kim Tae Hyum , Wang Pang Pang
Published: March 2010

In order to study the characteristics of multilayer thin films with a ZnO/ metal/ ZnO structure the manufacture of the thin films was performed by a dc (direct current) magnetron sputtering system on slide glass substrates. The ZnO thin films were manufactured with the thicknesses of 30 nm and 50 nm. Three kinds of metals (Ag, Al and Cu) were deposited with the thicknesses of 4 nm, 8 nm, 12 nm and 16 nm. The electrical and optical properties of the manufactured thin films were then observed. As a result, the multilayer thin films with an Ag layer represented the most excellent electrical conductivity. This is due to the difference in the fundamental electrical properties of each of the metals. The structures of the metal particles deposited on the ZnO thin films were observed by an SEM (scanning electron microscope). The thin films exhibited a continuous structure with regular spaces between the metal particles. This resulted in an increase of transmittance. This is considered by the decrease of scattering and of light absorption on thin films with a continuous structure.
Glass Fiber Permeability Using the VARTM Process
Authors: Kim Yun Hae , Yang Dong Hun , Bae Chang Won , Moon Kyung Man , Jo Young Dae , Yoon Sung Won , An Hee Beom
Published: March 2010

This study investigated a flow rate control system for the vacuum-assisted resin transfer molding (VARTM) process. Using Darcy’s equation, the permeability of multiaxial glass fiber composites is predicted and experimentally confirmed. The resin velocity vector is inversely proportional to the fiber mat length and resin viscosity, but proportional to the fiber mat permeability. In this study, the permeability of the preform and viscosity of the epoxy resin were measured using multiaxial glass fiber by VARTM. The permeability and time for impregnation differed according to the fiber direction in the VARTM process. The results indicated the need for further study of reinforcement fiber permeability in VARTM processing design.
Microscopic Analysis of Flow and Prediction of Effective Permeability for Dual-Scale Porous Fiber Fabrics
Authors: Yan Shi Lin , Lu Hang , Tan Hua , Qiu Zhong Qi
Published: March 2010

In this paper, the permeability of fiber fabric used in liquid composite molding (LCM) is predicted by the method of numerical simulation. The three-dimensional finite element model of unit cell representing the periodic micro-structure of a plaid is established. In the process of numerical simulation, each fiber bundle in unit cell is treated as a porous medium. Stokes equation and Darcy's law are employed to model the saturated flow between the fiber bundles and the saturated flow in the fiber bundle, respectively. Steady state flow of the finite element model of unit cell is simulated. The effective permeability of the plaid is obtained from the postprocessing of the simulation results by using Darcy's law.
The Study on the Surface Morphology of Al/SnO2-Sb2O3 or SnO2-Sb2O3-MnO2/PbO2 Electrode Material
Authors: Cao Mei , Guo Zhong Cheng , Cui Xia , He Su Qiong
Published: March 2010

SnO2–Sb2O3 or SnO2-Sb2O3-MnO2/ PbO2 electrode on aluminum substrate were prepared by thermal decomposition、electroless plating and electrodeposition .The surface morphology of coatings were investigated by using scanning electron microscope(SEM). The results show the effects of composition of solution and thermal oxidation temperature on the microstructures of the coating were considerable. The structure of oxide coating become refined with the thermal de- composition temperature increasing. The oxide coating without Mn is coarser than those with Mn. The surface of α-PbO2 and β-PbO2 deposited on the oxide coatings without Mn prepared at 450°C are compact and even, the electrocatalyst of the electrode is optimumest.
Analytical Modeling of Workpiece Surface Temperature Rise in Machining
Authors: Miao Zhi Yi , Yuan Shi Xian
Published: March 2010

In this paper, an analytical model is developed for prediction of temperature rise on workpiece surface during machining and orthogonal cutting is studied. The shear heat source created in the primary zone and the friction heat source on the tool-workpiece interface determine the workpiece temperature. The proposed model is verified with FEM simulation and experimental measurements of temperature on AISI4340 in the literature. With the analytical model presented here, substantial reduction in computational time is achieved in the predictions of machining workpiece temperature rise.
Research on Wear Mechanisms while Turning Titanium Alloy TC4
Authors: Liu Dong , Chen Wu Yi , Xu Hong Hai , Luo Xue Ke
Published: March 2010

Titanium alloys are widely used in aerospace industry due to their excellent mechanical properties. Because of their low thermal conductivity, high chemical activity, large friction coefficient and so on, such problems occur during the cutting process as high cutting temperature, large specific cutting force and serious tool wear, leading to low machining efficiency. The cutting force, forms of tool wear; wear mechanics were experimentally studied and analyzed while machining titanium alloy TC4 using carbide tools YS8 and YG8. The experimental results indicated that the tool wear of YG8 influenced cutting force not very remarkable when flank wear smaller than 0.25mm. But when the flank wear was bigger than 0.25mm, the cutting force increased rapidly with the flank wear increased. And the tool wear influenced the cutting force dramatically. The forms of tool wear during machining TC4 using carbide tool were adhesion wear, tool chipping and. The desquamation and chipping of tool caused by adhesion wear were the main reason of the tool failure.
Experimental Study of Improved Tool in High Manganese Steel Drilling
Authors: Yang Liang , Xu Li
Published: March 2010

Performance of tool has always been a puzzle in the course of high manganese steel drilling. In this paper, improvement of drill tool is been done on drill bit structure and parameters of cutting tip by means of analyzing geometric parameter. By utilizing simulation method correctly, the influence of bit parameter on drilling force is analyzed. Meanwhile, by adopting the way of dividing into groups, comparison experiment between improved and no improved has been done. The comparison analysis of test results is carried out including tool life, wear and drilling force. The conclusion showed that the improved bit has better performance.
Study on Causes of Material Plastic Side Flow in Precision Hard Cutting Process
Authors: Chen Guang Jun , Liu Xian Li , Yue Cai Xu
Published: March 2010

There are many special cutting disciplines needed to research in precision hard cutting process. The plastic side flow on machining surface influences machining surface roughness great. The mathematical model of hump height for surface plastic side flow is built based on the model of precision hard cutting and forming mechanism of surface plastic side flow is analyzed. Effect of cutting feed on the maximum scallop height of machining surface is researched and microscopic observation of surface topography is made through the hard cutting experiment. In certain conditions, the machining surface roughness and the cutting off trace increase with cutting feed. Because of the metal softening, some metal which formed side flow fall off immediately but make plastic flow on the strip edge of machining surface when it flows out tool surface. This research supplied theoretical basis for prediction of hard cutting process surface quality.