bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects and Mechanisms of Vanadium on Structural Transformation of BVRE Heavy Rail Steel
Authors: Huang Ya He , Liu Cheng Jun , Jiang Mao Fa
Published: November 2010

The different dilatometric curves of continuous cooling transformation with the different cooling rates were determined by means of Gleeble-2000 thermal simulation machine. The CCT curve of BVRE heavy rail steel was obtained by measuring the dilatometric curves and metallographic analysis. And the effects and mechanisms of vanadium on the phase transformation and microstructure of BVRE heavy rail steel were investigated. It is found that, the BVRE heavy rail steel only takes place pearlite and martensite transformation during continuous cooling. The CCT curve of BVRE heavy rail steel is moved to lower right with increasing vanadium content, which indicates that vanadium can obviously improve the stability of super cooled austenite and delay the pearlite transformation. When the content of vanadium is increased from 0.052% to 0.12%, the shortest incubation time of pearlite transformation is increased from 30s to 59s. When the cooling rate ≤ 5 ·s-1, with increasing vanadium content, both starting and finishing temperatures of pearlite transformation are decreased at different extent, meanwhile the pearlite is refined and the pearlite percentage is notably decreased. When the cooling rate is 2 ·s-1, the pearlite percentage is decreased from 65.7% to 35.9% with increasing vanadium content. When the content of vanadium is increased from 0.052% to 0.12%, the critical cooling rate of quenching is decreased from 13 ·s-1 to 7 ·s-1, thus the hardenability of BVRE heavy rail steel is improved.
The Optimization of Aluminum Foam Compound Board Structure Based on Machine Acoustic Enclosure
Authors: Yu Ying Hua , Yu Guo Jun , Yang Chun Hong
Published: November 2010

According to the structure of functional properties of aluminum foam, made machine noise enclosures with aluminum foam/steel composite panels was proposed. The mathematical model of sound energy transmission coefficient of aluminum foam/steel composite panel was established. Optimization the model through the MATLAB optimization toolbox gets the thickness and density of foamed aluminum on the best acoustic effects. It provides a reference for the design and manufacture of the lathe acoustical enclosure plate.
Drop Impact Behavior of Packaging System with Irregular Honeycomb Core
Authors: Chen Qiong , Lv Yuan Jun
Published: November 2010

For a product packaging system with honeycomb paperboard, its impact resistance caused by drop impact behavior had been concerned. However, irregular hexagon structure of the paper honeycomb core exists in package business, which is attributable to laggard glue applicator. It has an impact on its impact characteristics. Drop impact behavior of packaging system with irregular honeycomb core has been put forward to know its influence. First, on the basis of theoretical analysis, a series of honeycomb paperboards with different size dimension of paper honeycomb core had been set up in the FEA software. Then a packaging system which made up of rigid body and deformable body had been analyzed. The results show that the physical dimension of paper honeycomb core has a great effect on its impact resistance: with the increasing on degree of irregularity of paper honeycomb core, the peak acceleration has a quickly alteration. At the same time, when the length of glued edge is in near 4 mm and the girth of honeycomb core is 36mm, honeycomb paperboard can improve the energy absorption ability in the condition of elastic deformation. The research results can be used to optimize the structure design.
Evaluating Anti-Decay Effect of Rice Straw Based on Grey Correlative Method
Authors: Shi Qian , Chai Shou Xi
Published: November 2010

Anti-decayed rice straw may be used to reinforce saline soil in inshore of Northern China. Water absorption, maximum elongation and maximum tension of rice straw, including rice straw soaked in seawater, running water and seawater after SH agent has been tested, and anti-decay effect is evaluated based on grey correlative method. The experimental results showed that water absorption of rice straw soaked in seawater and running water increased with soaking time. And maximum elongation and maximum tension decreased with soaking time. The reduction rate of water absorption was the greatest when the rice straw was soaked in seawater after SH agent for 14-day and which had the biggest maximum elongation and maximum tension yet. According to grey correlative method, the relational degrees of water absorption, maximum elongation and maximum tension for 14-day are the biggest. It means that anti-decay effect is the best in this condition. Taking rice straw which soaked in seawater after SH agent for 7-day as example, correlation coefficients of water absorption, maximum elongation and maximum tension increase with soaking time. It indicates that the longer soaking time is, the better anti-decay effect of rice straw is. Evaluating anti-decay effect of rice straw according to grey correlative method and analyzing the laboratory results respectively, they are highly consistent. Grey correlative method is a suitable one for evaluating the anti-decay effect of rice straw.
Coercivity Metering as the Basic Method of a Non-Destructive Testing of Fatigue and as the Priority Method in the Diagnostic Set
Authors: Baskaran B.V. , Sreenivasan M. , Bezlyudko G.Ya. , Yolkina Ye.I. , Solomakha R.N. , Popov B.Ye.
Published: November 2010

Here "coercivity metering" or "coercimetry" (c.m.) means a non-destructive testing of the mechanical properties, deflected mode and fatigue capacity based on measurements of the magnetic characteristic of metal – i.e. coercivity. All listed below merits are most fully achieved when working with coercimeters (magnetic structure scopes) of SSE Company. And it is so not because the authors represent this company but rather because these devices feature a number of consumer and technical merits, which those of other manufacturers do not. Among them, the main thing is the highest clearance insensitivity i.e. when the device readings depend only on the properties of the metal, they do not depend on confounding factors, such as protective coating (paint, film, etc.) up to 6 mm (!) thick on the tested metal, or equivalent to such clearance corrosion layers, roughness, curvature of the surface, etc.
Experimental Study on the Corrosion Resistance of GFRPP Rebar in Alkali, Acid and Salt Solutions
Authors: Wang Chuan , Sui Li Li , Ou Jin Ping
Published: November 2010

More and more researchers took interests in FRP materials in civil engineering for their light weight, high strength and excellent durability performance. But common FRP rebars or plates used for reinforcing or strengthening in civil engineering are mostly made by fiber reinforced thermosetting polymer (FRSP) materials. While FRSP can not be reshaped so that many of the special shapes as bending rebar or hoop rebar cannot be easily obtained and handled at site. So, here we developed and fabricated Glass Fiber Reinforced Polypropylene (GFRPP) according to Fiber Reinforced Thermoplastic Polymer (FRTP) systems. This paper is focused on the experimental and theorial studies on the corrosion resistance of GFRPP rebar in alkali, acid and salt solution at different temperature. According to the corrosion experimental data, some durability life prediction would be concluded through FHWA method, and which may be valuable to a deeper understanding on the durability of GFRPP rebars. The results show that these kinds of GFRTP rebars have good resistance in acid and salt solution, and their mechanical properties can remain well, while bad resistance in alkali solution. As can be regarded that these FRTP rebars can be a vital support of common FRSP materials and which would play an important part in civil engineering in the future.
Fracture Test of E43 Solder Notched Bars at Low Temperature
Authors: Wang Wan Zhen , Ji Hai Tao , Hao Xu Chang , Wang Xin Tang
Published: November 2010

Fracture tests at low temperature (-47°C~-43°C) of 20 notched bars fabricated from E43 solder were conducted. The effect of notch radius, r, and notch depth, d/D, on fracture mode of E43 solder was studied. The experimental results demonstrate that cracks initiate at the center of notch section and the notched bars fracture at the notch section at low temperature. The fracture mode is cleavage fracture and the fracture sections are coarse. Specimens with a sharper notch radius (a smaller r) and a larger notch depth (a smaller d/D ratio) show poor ductility. The stress-strain curve of E43 solder tested on standard specimen at low temperature (-47°C~-43°C) exhibits the character of yielding, hardening and necking. The ratio of ultimate strength to yield strength, σu/σy, and the ductility, δ5, at low temperature meet to the requirement in plastic design for structural steel.
Influence of Electrode Argon-Hydrogen Co-Injection on Carbon Content in Ladle Furnace
Authors: Zhan Dong Ping , Zhang Hui Shu , Jiang Zhou Hua , Gong Wei , Chen Zhao Ping , Shen Hai Jun
Published: November 2010

The argon-hydrogen co-injection tests were carried out in a multifunction ladle furnace (LF) equipped with a hollow graphite electrode. About 80 kg low carbon steel were refined in LF, the argon-hydrogen gas mixtures were injected onto the melt through the hollow graphite electrode, the flow rates of the gas mixtures were 3 m3/h. Then, applying the plasma local equilibrium thermodynamics and metallurgical thermodynamics theories, a calculation model of argon-hydrogen plasma component concentration was established. Using this model, the particle densities of the argon-hydrogen system were calculated. The decarburization mechanisms during Ar-H2 injection in LF with hollow graphite electrode were studied. The results show that, in the process of traditional LF refining, the carburetion reaction occurs with using the graphite electrode. When the argon-hydrogen was injected into LF, there was a decarburization reaction on the interface of the melt. Compared with the traditional LF, the carburetion rate reduces 33.3% at least. The partial pressure of C2H2 produced by molecule hydrogen is far lower than that of CH4 reacted by monatomic hydrogen. The possible main reactant gas is monatomic hydrogen and the main product is CH4.
Study on MgO-Al2O3-TiO2 Inclusion in 409L Stainless Steel
Authors: Li Shuang Jiang , Huang Zong Ze , Jiang Zhou Hua , Li Yang , Chi He Bing , Chen Zhao Ping
Published: November 2010

The effects of deoxidization and wire feeding operation on the type of titanium, magnesium and aluminum spinel compound inclusion were investigated in 409L stainless steel production process. Further, the formation mechanism of the compound inclusion was also researched at the same time. The results show that the spherical compound inclusion formed in molten steel presents clearly hierarchy after Ti injection in VOD refining process, where the inclusion size is about 5μm to 10μm. The MgO-Al2O3-TiO2 phase of compound inclusion presents regular configuration. MgO and Al2O3 content in compound inclusion decreases gradually together with CaO and TiO2 content increasing from interior to exterior of inclusion. The biphase structure of MgO·Al2O3-TiO2 will be formed with TiO2 dissolving into MgO·Al2O3. On the condition that Ti content is controlled at 0.25 wt.% together with w(Al)<0.01 wt.%, TiO2 solubility is generally less than 20 wt.% in MgO·Al2O3-yTiO2, as y< 0.44.
Thermal, Mechanical, and Corrosive Behaviors of a Cu-Based Metallic Glass
Authors: An Wei Ke , Cai An Hui , Xiong Xiang , Liu Yong , Luo Yun , Li Tie Lin , Li Xiao Song
Published: November 2010

The thermal, mechanical, and corrosive properties for Cu50Zr40Ti10 (at. %) metallic glass were also investigated. The glass transition temperature Tg, onset crystallization temperature TX, and under-cooled liquid region △TX are 624.4, 691.1, and 66.7 K, respectively. The elastic strain, fracture strength, and elastic modulus are 2.13 %, 2099.78 MPa, and 86.85 GPa, respectively. The corrosion rates in 1 M HCl, 1 M NaCl, and 0.5 M H2SO4 solutions open to air at 298 K are estimated to be about 0.4759, 0.1076, and 1.758×10-3 mm/year, respectively. The passive films can be observed in HCl and NaCl but not in H2SO4, the corrosion products in the former are looser than those in the latter, resulting in the better corrosion resistance in the latter than in the former.
The Mechanics Behavior Tests of HPS-485W Made in China
Authors: Wang Chun Sheng , Duan Lan , Wei Ming , Liu Li Xiang
Published: November 2010

This paper gives a brief introduction of the developmental history of high performance steel (HPS) all over the world. Emphasis of current paper is on the characteristic studies of HPS 485W, which is new structural weathered steel produced by Wuyang Steel Iron Company using quenching and tempering (Q&T) in China. To obtain the strength and ductility of HPS 485W, the tensile coupons were machined from each 8mm, 10mm, 12mm and 14mm thick plate. Based on the static tensile tests in room temperature, major of material mechanical characters were obtained, such as yield strength, ultimate strength, elastic modulus and so forth. Besides, to examine plate toughness, 30 Charpy V-Notch (CVN) specimens from 12mm thick HPS 485W plate were tested from 20 oC to -196 oC . Compared with conventional bridge steels, the CVN test results show that the fracture toughness of HPS 485W is much higher, and the brittle-ductile transition of HPS occurs at a much lower temperature. A set of 9 single-edge bend specimens were took from 20mm and 30mm thick HPS 485W separately for ductility fracture toughness test. The calculated JIC value is 415.8 kJ/m2 for 18mm thick specimen and 507.79 kJ/m2 for 28mm thick specimen, which shows ideal ductility of HPS 485W.
Theoretical Model of Revised Powell Back Analysis of Composite T-Beam with Error Function
Authors: Zhang Jian , Lan Wen Gai , Lin Jing
Published: November 2010

Composite T-beam in general use is composed of concrete and steel. Compared with mechanical analysis, little research has been carried on deriving the theoretical model for back analysis of composite T-beam. Firstly for composite T-beam, degraded solid element theory is deduced and the displacement function is obtained. Then Markov error function of mechanical parameters of composite T-beam is founded. The back analysis computing formulas are also obtained by adopting optimization method including revised Powell method. Then the steps of back analysis of mechanical parameters of the composite T-beam are given. Through analysis of a classic example, some important conclusions about revised Powell back analysis of mechanical parameters of composite T-beam are obtained.
Thermal Oxidation of CP-Ti at Different Temperatures
Authors: Hu Jing , Wang Yan , Wang Da Yue
Published: November 2010

Thermal oxidation tends to improve surface performance of titanium and its alloys by thickening the native passive oxide layer. In the present work, investigation of thermal oxidation in a wide range of treating temperatures between 500-850°C was carried out for commercially pure titanium (CP-Ti) to determine the optimum thermal oxidation parameters by evaluating the corrosion resistance. Characterization of modified surface layers was made by X-ray diffraction analysis and surface hardness measurements. The results showed that the rutile TiO2 layer was formed on the surface of specimens, and the thickness of the TiO2 layer and the surface hardness increased with the treating temperature. Evaluation of corrosion resistance indicated that the optimum thermal oxidizing temperature was 700°C under air atmosphere.
Study on Rheocasting-Rolling of Semi-Solid AZ31B Magnesium Alloy
Authors: Zhang Ying , Xu Jin Hua , Xie Shui Sheng , Geng Mao Peng , Guo Hong Min , Zhao Hai Bo
Published: November 2010

Analysis on microstructure of semi-solid AZ31B magnesium alloy produced under different technological parameters were done, hot rolling experiments of AZ31B magnesium alloy semi-solid strips were carried out on the rheocasting-rolling machine which was developed by ourselves. The result shows that the strips after the rheocasting-rolling of AZ31B semi-solid magnesium alloy have good plasticity and rolling properties, this offers theory basis for reprocessing of AZ31B.
Preparation and Thermal Properties of P2O5 Doped Li2O-Al2O3-SiO2 Glass-Ceramics
Authors: Xiao Zhuo Hao , Zhou Jian Er , Luo Wen Yan
Published: November 2010

Using TiO2 and ZrO2 as compound nucleation agent, serials Li2O–Al2O3–SiO2 (LAS) glasses containing different content of P2O5 were prepared by conventional melt quenching technique and subsequent converting to glass–ceramics. The influence of P2O5 content on viscosity of LAS glasses was investigated in the temperature range from the softening point to melting temperature. DSC was undertaken to analyze the change of characteristic temperature Tg, Tc and Tp. Thermal expansion coefficient (TEC) of matrix glass and glass-ceramic containing different P2O5 were measured. The results show introducing P2O5 effectively decreased the melting temperature and viscosity of LAS glasses. TECs of the matrix glass and glass-ceramic range from 4.1×10-6 °C -1 to 5.3×10-6 °C -1 and from -0.2×10-6 °C -1 to 1.2×10-6 °C -1, respectively. XRD analysis indicates that β-spodumene is the main crystalline phase in the P2O5 doped LAS glass-ceramics, resulting in the low thermal expansion coefficient of the glass-ceramics.
The Hardness Changing Regularity of Quenched-Steel in Tempering Process and Its Double-Exponential Model
Authors: Guo Cong Sheng , Long Shu Ming , Bo Hai Wa , Tan Hong Bin
Published: November 2010

The transformation of tempering for quenched steel corresponded to complicated process of phase transformation, and mechanical properties of quenched-and-tempered steel were related to the phase transformation. In practice, hardness test was adopted to judge whether the properties of tempered-parts qualified because of its facility. Numerous researches indicated that, there existed correlativity expressed by different function forms between tempering hardness of quenched-steel and its tempering parameters. However, considering physical metallurgy of tempering process, the adoption of double-exponential function would help to describe regularity of hardness changing more exactly for quenched-steel during tempering process. Additionally, results of hardness tests for isothermal tempering and molding/simulation researches have shown that, the model of double-exponential function, which can reflect decline law of tempering hardness for quenched-steel, would provide basis for optimization design of tempering parameters, performance prediction of tempered-parts, and energy-saving heat-treatment on tempering process.
Effect and Solid Solution Mechanism of Co2O3 during C3S Formation
Authors: Tan Hong Bo , Ke Kai , Ma Bao Guo , Xiao Jun
Published: November 2010

C3S is one of the most important mineral phases in silicate cement clinker; alternative ions could be solidified into C3S crystal lattice. Therefore, the research on solid solution mechanism was studied, which was about C3S doped with ions, Meanwhile, the achievement of this paper could be taken as a guidance for cement clinker industry. The effect and solid solution mechanism of Co2O3 during C3S formation were studied by means of chemical analysis, XRD and phase diagram analysis. The results show that when Co2O3 additive was less than 1.5% in mass, the content of f-CaO increased with the increase of Co2O3, and the formation rate of C3S was accelerated by Co2O3; when Co2O3 addition exceeded 1.5%, the content of f-CaO decreased with the increase of Co2O3.By the least square method and defined f-CaO, the molecular formula that Co2O3 solidified in C3S could be deduced: (Ca3-0.86x Co0.86x) (Si1-0.14xCo0.14x) O5 (x=0.0209).
Influence of Low Tempering Temperature on Fracture Toughness of Ultra High Strength Boron Steel for Hot Forming
Authors: Ying Liang , Chang Ying , Hu Ping , Shen Guo Zhe , Liu Li Zhong , Li Xiao Dong
Published: November 2010

The influence of low tempering temperature (TT) on mechanical properties and fracture toughness of ultra high strength boron steel 22MnB5 for hot forming was investigated by tensile and Kahn tearing experiments. Compared with the conventional quenchable boron steel, The results show that the toughness of tested steel are both preferable when tempered at 200 , 40min. When TT between 100 ～200 , The tear strength (TS) and unit propagation energy (UPE) of quenched steel heightened along with the temperature raised, but in 200~350 temperature range, the toughness appears negatively growth. Appropriate TT could improve the mechanical properties and fracture toughness obviously, and the temper brittleness can be avoided.
Electrospark Deposition of Fe-Based Alloy Coating
Authors: Wang Jian Sheng , Zhang Rui Zhu , Yan Da Kao
Published: November 2010

Electrospark deposition (ESD) is a promising process to produce hard and wear-resisting coating on metallic substrates. Fe–Cr–Ni–Si–Mo–W–B–Co–Al alloy rods were used as electrode to produce coatings onto a high carbon cast steel roll substrate. Different parameters were used and the coatings have an average thickness of～80 μm, which are metallurgically bonded to the substrate. The microstructures of the coating prevail in nanosized grains and amorphous structures. The primary phases of the coating contain C0.055Fe1.945，(Fe,Cr)7C3，Fe7Mo3 and Al0.99Fe0.99Ni0.99. The maximum microhardness value of the coating is about 1837.4 HV. The study reveals that Fe-based ESD coating has a better quality and has a high hardness on the cast steel roll.
Effect of Pulsed Current on the Microstructure and Distribution of C and Mn in an Fe-0.5C-1.5Mn Alloy
Authors: Wang Hai Chuan , Hong Peng , Liao Zhi You , Li Xin , Lie Jie , Wang Gui , Wang Shi Jun , Dargusch Matthew S.
Published: November 2010

A pulsed electric current (19 kHz, 0-8 volts) has been applied to a molten Fe-0.5C-1.5Mn alloy to investigate its effect on the microstructure and the distribution of carbon and manganese. It has been shown that the pulsed electric field can improve the microstructure from a coarse banded structure to a compact acicular structure by increasing the pulsed voltage from 4 volts to 8 volts. The pulsed electric treatment also has an effect on the C and Mn distribution with a tendency for C and Mn to migrate to the cathode.
Comparing Age Hardening Behaviors of Al-3Cu and Al-8Si-3Cu Alloys
Authors: Wang Gui Qing , Liu Yan , Ren Guo Cheng , Zhao Zhong Kui
Published: November 2010

The aging hardening behaviors of Al-8Si-3%Cu (wt%) and Al-3Cu (wt%) alloys have been investigated. Samples were solution treated at 500 for 24 h followed by water quenching before aging. Hardness has been measured for quenched samples aging at 150°C. Strong age hardening occurs for Al-3Cu alloy and hardness increases by about 60% after peak aging. There is a hardness decrease in the early aging stage of Al-8Si-3Cu alloy and hardness increases by about 15% after peak aging. The age precipitation behaviors have been analyzed using DSC and TEM. Effects of microstructure characteristics on age precipitation and age hardening response of Al-8Si-3Cu alloy have been discussed.
Preparation and Modification of Nano- TiO2 Pigment for Coating
Authors: Zhang Xiao Hui , Cao Qi Guang , Hu Lin , Cui Jian Yu
Published: November 2010

Nanoscale titanium dioxide powder were prepared in terms of sol-gel process with Ti(OC4H9) as raw material. TEM analysis show that the size of nanoparticle are between 50～ 100nm.The results of XRD test indicate that the crystal style of the product is rutile type. In order to apply nanoscale titanium dioxide to coating as pigment, the nanoscale particles were modified in terms of esterifying reaction,silane coupling agent and organic titanate coupling agent. The results of contact angle test show that the oleophilic of modified product with organic titanate coupling agent is stronger than that with silane coupling agent and esterifying reaction.
Influences of Slag and Fly Ash on the Microstructure Property and Compressive Strength of Concrete
Authors: Cheng An Shun , Huang Chung Ho , Yen Tsong , Luo Yong Lin
Published: November 2010

This research aims to investigate the pore structures and the interfacial transition zone (ITZ) of concrete containing both slag and fly ash. Test variables include three water-to-binder ratios (0.35, 0.50, 0.70) and four substitute ratios of cement with pozzolanic materials (20%, 30%, 50% and 60%). The specimens were tested to determine compressive strength, MIP porosity measurement and ITZ microhardness. Test results show that concrete containing slag and fly ash produce evident filling effect and the pozzolanic reaction after 28 days. At the age of 91 days the pozzolanic materials has provided prominent contribution to the strength, the porosity and the ITZ of concrete, making the pore volume smaller and ITZ property of pozzolanic concrete better than that of normal concrete. The concrete that adds suitable amount of pozzolanic materials (ex. 10% slag + 10% fly ash) has the optimum microstructure and mechanical property. Too much pozzolanic materials (ex. 40% slag + 20% fly ash) may be disadvantage to the concrete, and the suggested substitute ratio is under 50%. It is found that the compressive strength has the closest relationship with the total pore volume, so we use the total pore volume to predict the compressive strength of pozzolanic concrete and establish a prediction model as follow: S= -662.68Vt+87.29, R2=0.946.
Microstructure and Creep Property of As-Cast Mg-6Al-xNd (x=2,4,6) Alloys
Authors: Wu Yu Feng , Du Wen Bo , Zhang Yi Nan , Zuo Tie Yong
Published: November 2010

The microstructure and creep property of as-cast Mg-6Al-xNd(x=2,4,6) alloys were studied in this paper. Results showed that the needle-like Al11Nd3 phase and polygonal Al2Nd phase are the main precipitates in these alloys containing Nd, and the weight fraction of the former is much more than that of the latter. Their secondary creep rates under the applied stress of 70MPa at 175°C decreased with the content of Nd increasing and reached the minimum value of 5.0×10-8s-1 in the Mg-6Al-6Nd alloy, which is one ninth of that of the Mg-6Al alloy. The improvement in creep property of these alloys containing Nd was mainly attributed to the needle-like Al11Nd3 phase, which hindered the grain boundaries sliding and dislocation motion effectively in the creep.
Effective Service Life Assessment of Aluminum Alloy Alclad Corrosion Protection under Equivalent Accelerated Condition
Authors: Zhang Dan Feng , Tan Xiao Ming , Chen Yue Liang , Sun Fu Juan
Published: November 2010

It’s very important to describe the corrosion damage evolvement rule of the aircraft structure for evaluating the calendar life. According to equivalent accelerated corrosion testing spectrum based on key environment data, the corrosion damage of accelerating corrosion testing for 7d is equivalent to that of field exposure for 1a. The new aluminum alloy of aircraft structure has been accelerated tested for 10a. Through KH-7700 3-D optical microscope, corrosion damage was inspected and measured. The result shows that some independent pits generate on the alclad surface in the first, and then many pits interconnect leading to the bigger holes. The effective service life of the aluminum alclad was gotten under equivalent accelerated corrosion testing condition.
Bismaleimide Matrix Composites with High Wear Resistance Modified by Potassium Titanate Whiskers
Authors: Hu Xiao Lan , Lin Zhong , Yu Mou Fa
Published: November 2010

Tribological behaviors and wear mechanism of bismaleimide resin and its composites modified by potassium titanate whiskers were investigated. The composites with outstanding tribological properties were prepared through several coupling agents and whisker contents under different friction loads. The incorporation of whiskers treated with silane into the matrix effectively improved wear properties and friction stability of the matrix, especially at severe friction condition as 30 kg. The wear volume of the neat resin at 15 kg and 30 kg friction load are 1.14 and 6.87 mm3, respectively. However, the wear volume of the composites containing 3 wt% potassium titanate whiskers at 15 kg and 30 kg friction load are 0.75 and 1.14 mm3, respectively. Furthermore, the addition of whiskers increased the ability to resist plastic deformation and crack of the matrix in a higher friction load.
Effect of Microcracks on the Toughness of Particulate Composites
Authors: Qu Hong Chang , Xia Xiao Zhou , Xiong Zhi Qiang
Published: November 2010

The crack tip region in an elastic composite can be separated into three different regions. based on a simple rate-independent phenomenological constitutive model, the path independence of the J-integral and the concept of cracktip shielding, the maximum radii R of the damage saturation zone is obtained. Damage isotropy in the largest saturated damage zone is expressed by utilizing the Monte-Carlo technique to create the uniform distributions of microcrack location and orientation. With the assumption of dilute microcrack concentration, interaction among microcracks are neglected, and the stress intensity factor produced by interaction between main-crack and each microcrack can be superposed. Two sources of loading are analyzed, one is for the main-crack microcrack interaction under an applied remote load, and the other is for the main-crack microcrack interaction accompanied by the relief of residual stresses on the microcrack surfaces. The results show that two sources of loading can shield the main-crack tip, and microcracks behind the main-crack tip can make the most shielding whereas microcracks ahead of the main-crack tip play no role in shielding.
Mathematical Model of Relation between Microstructure and the Yield Strength of High Carbon Steel Wire Rods
Authors: Feng Yun Li , Li Jie
Published: November 2010

Ferrite content and the plate distance of pearlite of high carbon steel wire rod are analyzed by Optical Microscope and SEM, using quantitative microstructure analysis technology. The relation between microstructure and yield strength of high carbon steel wire rods was investigated. And the mathematical model of the relation was established as: σs(Pa)=104.52×106+161.70(1－fα 1/3)S－1(m). It was validated by experiment data that the mathematical model agrees well with the experimental results.
Behaviors of Carbon in Different Concentration of Sulfuric Acid
Authors: Zhao Rui Rui , Shu Dong , Chen Hong Yu
Published: November 2010

N2 adsorption-desorption method, scanning electron microscope and transmission electron microscopy were employed to test changes of the specific surface area, average pore diameter and appearances of activated carbons treated with different concentration of sulfuric acid. It can be concluded that these performances altered with sulfuric acid concentration. Activated carbon can be oxidized when the acid concentration increase to a certain value and this process takes time that sulfuric acid molecules first insert in the pore of the carbon which represented by reduction of the specific surface area of carbon and then oxidization occurred. This study is very significant in the development of carbon which is suitable for lead acid battery.
Photocatalytic Degradation of Methylene Blue Using Immobilized Nanoparticles of TiO2 Supported by SBA-15 Surface
Authors: Li You Ji , Chen Wei , Li Lei Yong , Ma Ming Yuan
Published: November 2010

TiO2-SBA-15 surface (TSS) composites were prepared by the supercritical pretreatment and then sol-gel process with using paraffin used as a clogging agent. The as-grown materials were characterized by using X-ray diffraction, UV-VIS spectroscopy and nitrogen absorption. The photocatalytic activities of TSS were evaluated by quantifying the degradation of methylene blue solution under UV light. Compared with TiO2-SBA-15 (TS) composites prepared only by the sol–gel method, TSS composites remain in mesostructure with high surface areas due to clogging effect of paraffin on SBA-15 cavity. Additionally, the small crystalline size of TiO2 in TSS is attributed to the fact that silica support baffles the agglomeration ofTiO2 nanoparticles. In comparison of TS composites and pure TiO2, higher photocatalytic activity of TSS is obtained and mainly attributed to larger surface areas and greater band-gap energy.
Evaluation on the Effect of Weld Shape on Fatigue Performance by Analytic Hierarchy Process
Authors: Liu Xin , Gong Shui Li , Lei Yong Ping
Published: November 2010

Four different weld shapes were obtained by choosing appropriate electron beam welding parameters, which are respectively named as bell shape, funnel shape, nail shape, and wedge shape. Fatigue examinations of the electron beam welded joints with different shapes were carried through. The influence of weld shape on fatigue performance of the joints was synthetically evaluated by analytic hierarchy mathematical model. The results show that weld shape effects fatigue property of the joint by electron beam welding. The sequencing of fatigue performance of the joints with four different shapes by analytic hierarchy process is bell shape, funnel shape, wedge shape, and nail shape. It is validated by practical trial results that the analytic hierarchy mathematical model is effective and practical.
Isothermal Transformation of Low Temperature Super Bainite
Authors: Hu Feng , Wu Kai Ming
Published: November 2010

Fine-scale bainitic microstructure with excellent mechanical properties has been achieved by transforming austenite to bainite at low temperature ranging from 200oC to 300oC. Microstructural observations and hardness measurements show that transformed microstructures consist of bainitic ferrite and carbon-enriched retained austenite. The thickness of bainitic ferrite plates is less than 50 nm. The hardness reaches approximately 640 HV1. Strong austenite and/or large driving force at the low transformation temperature leads to ultra fine bainitic ferrite plates. X-ray diffraction analysis indicates that low-temperature bainite transformation is an incomplete reaction. The carbon content in carbon-enriched retained austenite is below the para-equilibrium (Ae3′) phase boundary predicted. The carbon content in bainitic ferrite is less than that T0′ phase boundary predicted.
Studies on the Processes Design of Multi-Step Sheet Metal Forming
Authors: Chen Wei , Wu Ming Yan , Huang Zhong Fu , Ding Yi , Dai Feng Ze
Published: November 2010

It is well known that the design of multi-step sheet metal forming process is rather difficult. Even small errors may cause significant quality problem. In recent years, finite element analysis (FEA) has being considered as an essential tool for the design. Using a commercial FEA package, DYNAFORM, this paper studies the design of multi-step sheet metal forming processes, especially on how the design of the intermediate steps affect the forming quality. For a rectangle box with a rectangle protrusion inside, several different forming schemes are investigated by means of FEA. The study reveals that the strain path plays an important role. Accordingly, a couple of design rules are suggested.
Study on Heat Treatment of Nitrogen H13 Steel
Authors: Chen Yu Lai , Liu Biao , Li Jing Yuan
Published: November 2010

Composition segregation and microstructure nonuniform of H13 steel have been obviously improved though adding nitrogen element. The microstructure and property of H13 steel with nitrogen contents of 0, 0.021%, 0.058% and 0.085% are studied under various quenching and tempering states. Dual quenching that is quenching between 1000~1010°C twice is employed in order to increase the tensile strength and hardness of coupons. The temperature and time are explored for improving the toughness under optimal quenching treatment. For extruding die steel, the tensile strength can reach a satisfactory level and impact toughness are met the requirements of NADCA at the temperature.
Fabrication of Carbon Fiber Embedded Carbon Aerogel via Supramolecular Assembly of Small Molecules in the Precursor Gel
Authors: Li Yuan Gang , Li Hua Jing , Liu Bo , Zhou An Ning , Xi Xiao Gang
Published: November 2010

Carbon fiber embedded carbon aerogel (CFECA) was fabricated through simple addition of small organic gelators to the precursor formed by furfural and resorcinol. The surface area of the obtained CFECA decreased compared to that from the precursor without small gelator, but the electrical conductivities of the CFECA increased obviously. The maximum conductivity of the CFECA can reach 2.55 × 105 S/m which is more than three times as that of the referenced common carbon aerogel. The formation of CFECA was characterized by SEM as well as TEM observation.
316L Stainless Honeycombs Fabricated by Extruding and Sintering
Authors: Zhou Yun , Zuo Xiao Qing , Zhang Ting
Published: November 2010

Pure 316L powder is used to mix with an additive to prepare a powder mixed paste. 316L honeycombs were fabricated by extruding the powder mixed paste, then dried and sintered. The volume shrinkage and the apparent density of extruded honeycombs after drying and sintering were measured. The effect of sintering temperature on the volume shrinkage, the apparent density and the structure of honeycombs had been studied. The results show that the volume shrinkage and the apparent density of sintered honeycombs increase with sintering temperature from 1120°C to 1200°C , the volume shrinkage varying from 42% to 57%, and the apparent density from 1.9 to 2.9g/cm3 for 80% solids fraction. The volume shrinkage decreases and the apparent density increases with solid fractions increasing. The structure of sintered honeycombs consists of matrix phase α-Fe(Cr,Ni) , complex compounds of silicon, oxygen and inclusion elements. There is oxide film forming on surface of sintered honeycombs.
The Microcontact Analysis of Contact Length between Wheel and Workpiece in Precise Grinding
Authors: Horng Jeng Haur , Wei Chin Chung , Chen Yang Yuan , Chang Yuh Ping
Published: November 2010

This paper analyzes theoretically the contact length derived from elastic-plastic mechanics and microcontact theory with the aim of improving the traditional method of predicting roughness factor though experiments. The accuracy of the analysis is verified through experiments. It transpires from the theoretical model that the contact length between a grinding wheel and a workpiece increases with decreasing curvature radius of peak, increasing hardness of the workpiece as well as increasing depth of cut. It is also revealed that the contact length is directly proportional to the square of 0.32 of the hardness, approximately, whilst the square root of surface roughness and the density of peak of the grinding wheel show less influence on the contact length. The analysis method has reduced the variation between predicted and experimental values than that of the old methods. These results will be beneficial in analysing and designing the product quality of grinding.
Non-Local Stress and Stain Analysis at Crack Tip Based on Different Types of Weighted Functions
Authors: Wang Zhong Chang
Published: November 2010

The characteristics of different types of the weighted functions are discussed, and the dependency of the influence domain on the intrinsic length scale is examined. Distribution of stress field of I-II mixed mode crack is analyzed by non-local theory with different types of weighted functions. The effects of the stress intensity factor KI and KII on the all components of strains at the crack tip are analyzed by the non-local theories based on different types of weighted functions. The non-local strain will be considerably reduced. The size of non-local strain field with the bell-shaped weighted functions is larger than that obtained by either Green’s or Gaussian weighted functions. The non-local theory is instructive to avoid the trouble resulting from stress singularity at crack tip.
Research on Design and Pavement Performance of TLA Modified Asphalt Mixture
Authors: Feng Xin Jun , Zha Xu Dong , Hao Pei Wen
Published: November 2010

Marshall test design methods are used to design TLA modified asphalt mixture and base asphalt mixture respectively, and their pavement performance is tested. The results showed that there is a transforming coefficient of 1.15 between OAC of TLA modified asphalt mixture and that of base asphalt mixture, and ultimate gradation of the TLA modified asphalt mixture is finer than previous gradation. TLA modified asphalt mixture has excellent high temperature stability, capacity of moisture-resistance damage and impermeability. So it can be applied to asphalt pavements engineering of expressway in China.
Deformation Mechanism in the Mg-Gd-Y Alloys Predicted by Deformation Mechanism Maps
Authors: Hou Qing Yu , Wang Jing Tao
Published: November 2010

Deformation mechanism maps at 0-883 K and shear strain rate of 10-10-10+6 s-1 were built from available rate equations for deformation mechanisms in pure magnesium or magnesium alloys. It can be found that the grain size has little effect on the fields of plasticity and phonon or electron drag, though it has important influence on the fields of power-law creep, diffusion creep, and Harper-Dorn creep in the maps within the present range of temperature, strain rate, and grain size. A larger grain size is helpful to increase the field range of power-law creep but decrease that of diffusion creep when the grain size is smaller than ~204 μm. Harper-Dorn creep dominates the deformation competed to diffusion creep in the grain size range of ~204-255 μm. The maps include only plasticity, phonon or electron drag, and power-law creep when the grain size is higher than ~255 μm, then the grain size has little influence on the maps. Comparison between the reported data for the Mg-Gd-Y alloys and the maps built from available rate equations, it can be conclude that the maps are an effective tool to predict or achieve a comprehensive understanding of the deformation behavior of the Mg-Gd-Y alloys and to classify systematically their discrepancies in the deformation mechanism. However, differences exist in the deformation mechanisms of the alloys observed by the reported data and that predicted by the maps. Therefore, refinement of the maps from the viewpoint of mechanical twining, DRX, and adiabatic shear are necessary.
Microstructure Characterization of Large Strain Deformed Fe-32%Ni Alloy
Authors: Liu Bai Xiong , Han Bao Jun
Published: November 2010

High-resolution electron backscatter diffraction (EBSD) in scanning electron microscope and transmission electron microscope (TEM) were used to investigate the microstructure of Fe-32%Ni alloy processed by large strain multi-axial forging. The samples were compressed with loading direction changed through 90º from pass to pass at temperature of 500°C and a strain rate of 10-2/s. The results show the microstructure evolution is characterized by full development of almost equi-axed fine grains, not well-developed grain boundaries accompanied by high dislocation density and the existence of extensive extinction contours in the vicinity of grain boundaries, and the structure characteristics indicate that the grain boundaries are in a non-equilibrium state with high internal stresses.
Investigations on the Textured Bi3NbTiO9 Ceramics via Spark Plasma Sintering
Authors: Li Bao Rang , Cheng Yin , Zheng Yang Sheng
Published: November 2010

This paper reported results of an investigation aiming at finding what affected the orientated grain growth of Bismuth titanate niobate (Bi3TiNbO9) by spark plasma sintering process (SPS). Single phase of textured Bi3TiNbO9 (BTNO) ceramics were prepared by a two-step sintering method: synthesizing seed-crystal platelets by molten-salt method with oxide mixture as precursors and then sintering the platelets under different SPS conditions such as heating rate, holding time, sintering temperature and pressure, etc. The possible effects of these factors upon the textured microstructure have been analyzed in detail. Textured Bi3TiNbO9 ceramics with different orientation degree was obtained by controlling the conditions during SPS process.
The Electromagnetic Mechanism of Pulsed Electric Discharge on Directionally Solidified Microstructure of Pure Aluminum
Authors: Zhao Zhi Long , Su Jian , Liu Yan
Published: November 2010

The effect of high density of pulsed electric current on directional solidification of pure aluminum was investigated. The solidified microstructure experiences three evolution stages with increasing of current density, which are regular columnar structure to cellular crystal, cellular crystal to dendrite, and dendrite to columnar crystal. The influence of pulsed electric current on microstructure was analyzed by means of coupling effect between induced electromagnetic field and electric current.
Analysis of Carbide Precipitates in API X80 Medium-Thickness Plate
Authors: Kong Xiang Hua , Wang Shuai , Sun Yan Hui , Zhang Jian Liang , Li Xiang , Wang Fa Cang , Geng Jian Lin
Published: November 2010

In order to discuss the abnormal fracture in drop weight tear test (DWTT) of API X80 medium-thickness plate, some unqualified samples in DWTT are characterized by SEM, AES, electrolysis and thermal simulation. SEM results show that there are many spherical precipitates in the fracture surface. EDS and AES results show that the abnormal spherical precipitates are carbides including Fe, Ni, Mo, Ti, etc. These precipitates can be extracted by neutral electrolyte method and their EDS results further demonstrate they are carbides. The formationmechanismof the precipitates is discussed based on thermal simulation experiments. When the cooling rate of medium-thickness plate is not enough high, especially in carbide formation area in Fe-C diagram, abnormal spherical carbides will occur and they are harmful for DWTT.
Elongational Rheology of LLDPE by Melt Spinning Technique
Authors: Xu Hai Hang , Zhong Lei , Liang Ji Zhao
Published: November 2010

Elongational rheology of LLDPE was studied by melt spinning technique. It was observed that the melt strength of LLDPE decreased with the rise of temperature, and the melts with lower elongational viscosities often broke at higher draw ratio. The melt strength activation energy was calculated by the slope of Arrhennius plots. The curves of elongational stress and viscosity under different conditions were drawn and compared, the results showed that with the increase of strain rate, the elongational stress rose and the viscosity decreased, both stress and viscosity dropped with the rise of temperature, and higher extrusion velocity caused lower elongational stress and viscosity.
A Study on Morphologies of Second Phases in the Mg-Sr and Mg-Sr-Y Alloys
Authors: Gao Jing , Yu Hai Cheng , Zhao Fang Fang , Hu Ming
Published: November 2010

In this paper, the author successfully fabricated Mg-Sr and Mg-Sr-Y alloys by melting-leaching reduction method using SF6 and N2 as protected gas. The micro-structures of the alloys were investigated in details，and the results showed that dendrite α-Mg and eutectic α-Mg and Mg17Sr2 were the main phases in the Mg-Sr alloy, while Mg -Sr-Y alloys were composed of dendrite α-Mg and small eutectic α-Mg and Mg17Sr2 and tiny Mg24Y5. More eutectics were distributed around dendrite crystals in the Mg-Sr alloy, the Mg17Sr2 with aspect ratio of 6 : 1 were aligned and discontinuous lamellae, a Mg17Sr2 was irregular particles. The microstructures of Mg-Sr-Y alloy refined, Mg17Sr2 and tiny Mg24Y5 particles with size of 2-3μm distributed in the α-Mg dendrites and boundaries. The fomation and growth of both Mg24Y5 and Mg17Sr2 in the alloys were stated. It is obvious that the role of improving the heat-resistant Mg alloy of Mg24Y5 is more than Mg17Sr2.
Study on the Formability of Different Gauge Tailor Welded Blanks Based on Tensile Test
Authors: Xue Song , Zhou Jie , He Ying Qiang
Published: November 2010

The formability of different gauge tailor welded blanks is difference to single material blanks. As an effective and practical material property test method, tensile test were applied to study it. Base material and tailor welded blanks test specimens had been designed for tensile testing. The results of tensile test indicated that the strength difference and weld line location in the TWBs plays an important role on the formability aspect.