bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Nb on Strain-Induced Precipitation of NbC and Static Recrystallization for High Nb Pipeline Steels
Authors: Qiao Gui Ying , Xiao Fu Ren , Zhang Xiao Bing , Chen Shao Hui , Liao Bo
Published: November 2010

Strain-induced precipitation of complex carbonitrides and recrystallization for three high-Nb pipeline steels with different Nb and C content have been studied by using a stress relaxation technique and two-passes interrupted compression test. Sequentially, the PTT diagrams were obtained, and static recrystallization activation energy was calculated. Furthermore, the effects of Nb and C content on strain-induced NbC precipitation and static recrystallization were discussed. The results confirm the faster kinetics of precipitation and its retarded recrystallization in the case of higher Nb pipeline steel, and that the recrystallization is easier in low Nb pipeline steel in comparison to the case of high Nb steel. However, the effects of Nb on strain-induced precipitation and static recrystallization were associated with the Nb/C ratio. The precipitation start time (Ps) of strain-induced NbC is delayed in lower Nb/C ratio pipeline steel. It is suggested that the reduced supersaturation of Nb can result in the delay of precipitation of strain-induced NbC carbides forming in the low Nb/C ratio steel.
Early Age Hardening Response of Al-Cu-Mg Alloys
Authors: Chen Zhong Wei , Fan Li , Chen Pei
Published: November 2010

The early age hardening behavior in Al-Cu-Mg alloys with fixed Cu content (0.50 wt%) and varying amounts of Mg has been studied by hardness tests and TEM observation. Two alloys both exhibit the early rapid hardening phenomenon based on large solute-aggregates analysis. Ageing time of early stage rapid hardening of Al-0.5Cu-1.99Mg alloys is less than that of Al-0.5Cu-1.48Mg alloys. For two alloys, ageing time of early stage rapid age hardening reduces with artificial ageing temperature increasing. The early stage rapid age hardening is depended on the composition and artificial ageing temperature. Forming larger solute-aggregates may give rise to early rapid age hardening.
Strain-Hardening Behavior of Mg-Li-Zn Alloy Thin Sheets under Tension
Authors: Wu Horng Yu , Sun Pin Hou , Chiu Chui Hung , Zhou Geng Zhong
Published: November 2010

This work examined the effects of Li content on the strain-hardening behaviors of three varieties of Mg−Li−Zn alloys containing approximately 6 wt%, 9 wt%, and 10 wt% of Li. Tensile tests were carried out on specimens in the directions of 0, 45 and 90° to the rolling direction. Kocks–Mecking type plots were constructed to illustrate different stages of strain-hardening. The cold-rolled Mg−6Li−1Zn (designated as LZ61) alloy sheet showed stage II and stage III strain-hardening behaviors at room temperature. The specimens of Mg−9Li−1Zn (designated as LZ91) and Mg−10Li−1Zn (designated as LZ101) alloy sheets did not show stage II strain-hardening. Higher initial strain-hardening rates were observed in the 90° direction for these alloys as a result of the cold-rolled fibrous structure affording stronger barriers to dislocation movements in this direction.
On the Tensile Experiments of the Woven Membrane Materials under Bi-Axial Loads
Authors: Chen Shou Hui , Guo Zheng
Published: November 2010

As a kind of flexible fabric reinforced composites, the woven membrane materials suffer from the bi-axial tensile loads in the application of the lightweight structures. Therefore, the experiments under bi-axial tensile loads are essential for the acquaintance of the mechanical characters of the membrane materials. This paper has summarized thoroughly the details of the bi-axial tensile tests, especially the in-plane cruciform tests. The aspects include the shape and configuration of the cruciform sample, the practice of the applied stresses and the testing of the strains in the two axial directions. It could be expected to be the reference for the establishment of the testing standard of the bi-axial tensile experiment for the membrane materials.
Fracture Analysis of Plates with Elliptical Hole Fabricated from Q235 Steel
Authors: Wang Wan Zhen , Ji Hai Tao
Published: November 2010

Fracture tests of 10 plates with elliptical hole fabricated from Q235 steel with the thickness of 4mm were conducted. The effecting of sharpness of elliptical hole (a/b) on fracture mode and fracture ductility of structure steel was studied. The experiment results show that the first crack initiates at the edge of the major axis of elliptical hole and expands towards the thickness of the plates. And then the crack expands quickly vertical to loading direction until the specimen ruptures. The fracture ductility is low for the specimen with the sharp elliptical hole. Numerical simulation and analysis of Q235 steel plates with elliptical hole were implemented based on an elliptical yield model and an elliptical fracture model. The simulated stress field shows that the stress concentration severely at the edge of the major axis of elliptical hole. The accuracy of the proposed elliptical fracture model is proved for predicting the fracture of Q235 thin steel plates with elliptical hole.
Enhancement of the Fatigue Property of the Crack of Cruciform Welded Joints by TIG-Dressing
Authors: Li Dong Xia , Jia Bao Chun , Zhu Yan Zhi
Published: November 2010

The effect of TIG-dressing on fatigue strength in support of the fillet weld of offshore platform was investigated experimentally in the paper. According to the causes in which most cracks are produced in actual structure, the model tests have been performed based upon cruciform weld bead characteristic. The TIG-dressing technique parameters were established by the actual structure and the fatigue specimen tests were done also. The life estimation equation after TIG-dressing is presented by least square method. The fatigue life used by TIG-dressing has increased over 100%. Therefore the TIG-technique gives a big potential for engineering application.
Rapid Fabrication of Micro Optical Elements Using DMD-Based Maskless Lithography Technique
Authors: Guo Xiao Wei , Dong Qi Ming
Published: November 2010

A low-cost microfabrication tool based on digital mirror device(DMD) is presented in this paper. The imaging principle of the system is described and the fabrication methods for binary and nonbinary micro optical elements(MOE) are also discussed in detail. It is expected to provide an understanding of MOEs fabrication using DMD-based maskless lithography technique.
Measurement and Analysis of Fabric Capillary Radius Distribution
Authors: Di Jian Feng , He Xiao Xia , Qi Hong Jin
Published: November 2010

In this paper, a new capillary model and weight-classification method are proposed and a device is designed and fabricated, which is helpful to measure the μm-scaled pore size of fabric and hence accurately control wet processing and heat-moisture transportation in fabric. The histograms and curves show that the pore size distribution for the cotton fabric used is generally in the range of 49-2391μm exhibitng a continuous character, different from the conventional geometric jumping distribution observed by microscope. Using four classes with different width, the obtained data show that the absolute deviation region is in 2-32μm, while the relative deviation is less than 0.1%. It is found that the radius range reduces but the absolute and relative deviation fluctuate with increasing the width.
Metal Content Determination of Metallized Fiber by Density Testing
Authors: Ao Li Min , Zheng Yuan Sheng
Published: November 2010

Metal content of metallized fiber can be determined by density testing and calculating. The weight of plated metal’s percentage of metallized fiber can be derived form measuring the weight of metallized fiber, and using the density formula and the law of conservation of mass with knowing the density of plated metal and the basic fiber. The characterization and measurement of the metal content of the metallized fiber at home and abroad is compared, the principle of the determination method by density testing is analyzed, the principle of the determination method by density testing is analyzed, and the specific operation is discussed while the silver content determination of silver-plated fiber is as an example, which provides a simple and convenient means for the determination of metal content of the metallized fiber..
Sr1-xNdXFe12O19 Ferrite Synthesized through Sol-Gel Self-Combustion
Authors: Wang Zhan Yong , Jin Ming Lin , Qian Hui Chun , Fang Yong Zheng , Xu Jia Yue
Published: November 2010

Sr1-xNdxFe12O19 ferrites were Synthesized via sol–gel and self-combustion methods with Fe(NO3)3·9H2O，Sr(NO3)2 and citric acid. The as-synthesized powder was studied by differential scanning calorimeter (DSC). X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) were applied to investigate the structure and magnetic properties. The powder was synthesized in different calcination temperature and doping content of Nd2O3. The experiment reveals that the magnetic properties of Nd3+ doped ferrites are less sensitive to calcination temperature comparing with no doping ferrites. The coercivity (Hcj) of Nd3+ doped ferrites reach 423.96 kA·m-1.
Effect of Ti, Zr and Mg Addition on the Impact Toughness of Heat Affected Zone in Low Carbon Steel
Authors: Ma Jiang Hua , Zhan Dong Ping , Jiang Zhou Hua , He Ji Cheng , Yu Jin
Published: November 2010

In order to understand the effects of deoxidizer such as titanium, zirconium and magnesium on the impact toughness of heat affected zone (HAZ) of steel, four low carbon steels deoxidized by titanium, zirconium and magnesium were obtained. After smelting, forging, rolling and welding simulation, the effects of Ti, Zr and Mg additives on the impact toughness of HAZ in low carbon steel were studied. The inclusion characteristics (size, morphology and chemistry) analysis, Charpy-type test and the fracture observation of the specimens after the Charpy-type test were carried out respectively. The following results were found. The density of inclusion in Ti-Zr-Mg deoxidized steel is maximal. With the increasing of Ti content in steel, the proportion of inclusions in diameter less than 0.5 μm decreases. The proportion reaches maximum 64.0% in Ti-Zr-Mg deoxidized steel. The addition of Ti-Zr-Mg can enhance the impact toughness of HAZ after welding simulation. The maximal impacting energy is 249J at 253K. The complex particles of MgO-ZrO2-TiOx-MnS are most benefit to enhance impact toughness. The improvement of HAZ is attributable to the role of particle pinning and the formation of intergranular ferrite.
Theoretical Modeling and Simulations of Magnetic Fluids in Gradient Magnetic Fields
Authors: Peng Xiao Ling , Yang Xiao , Wei Hai Biao , Yue Rui Ping , Ge Hong Liang
Published: November 2010

When a magnetic field is applied to magnetic fluids (MF), various structures of MF are formed: chain-like structures in low fields, columnar, lamellar and striped structures in high fields, ellipsoidal structures in pulsed fields, and layered structures in rotating fields. The inner structures and particle distributions of MF in gradient magnetic fields are quite interesting, but very few works have been done on this. In the present study, the effects of magnetic field gradient on the structures of MF are investigated using a two-dimensional Monte Carlo simulation. The results show that a gradient distribution of magnetic particles is formed under gradient magnetic fields. Moreover, with increasing the field gradient, more magnetic particles are pushed to the right region and particle distribution changes from grass-like clusters to needle-like ones.
Impact Test on Steel Structures - An Experimental Investigation
Authors: Nuawi Mohd Zaki , Bahari Abdul Rahim , Abdullah Shahrum
Published: November 2010

The dynamic responses of the impact phenomena were studied experimentally using ultrasound transducer mounted at the specimen support to capture non-audible structure-borne acoustic signal generated during the impact event. A series of low velocity as well as full capacity impact tests were analysed. Analysis from the time histories record and the signal energy from the power spectral density show that the transient signal generated during the impact event have relation to the impact velocity and impact energy. This paper can be further studied in order to characterise the material properties.
Characteristics Analysis of Coir Fiber and Performance Evaluation of Coir Fiberboard
Authors: Yao Jia , Hu Ying Cheng , Lu Wei , Li Jin
Published: November 2010

SEM observations of coir fiber microstructure have been carried out. Uneven surface characteristics are conducive to the bonding between coir fibers and resin materials. The unique advantages of coir fiber have been verified. Doing orthogonal experiment design for coir fiberboard, the coir fiberboard can meet the mechanical properties of National Standards of China. The various factors optimization plan on the performance of coir fiberboard has been obtained. FFT nondestructive testing has been done for the coir fiberboard. Nondestructive testing results show that the good correlation exists between dynamic mechanical properties and the static test results.
Aging Behavior of T91/10CrMo910 Dissimilar Steel Welded Joints
Authors: Yao Yu Hong , Wei Jian Feng , Liu Jiang Nan , Wang Zheng Pin , Jin Yao Hua
Published: November 2010

The microstructure and property of T91/10CrMo910 dissimilar steel welded joints after one and two years service have been studied by OM, TEM, EDS and Vickers hardness test in this paper. The results showed that after one year service the microhardness of T91/10CrMo910 dissimilar steel welded joints increased clearly and after two years service chromium element diffused or transferred from the welding line or T91 matrix to 10CrMo910 matrix. Coarse lath martensite was the characteristic of the microstructure of T91/10CrMo910 dissimilar steel welded joints, and the martensite laths became fragment after one and two years service. More carbide particles had been observed after one year service than that after two year service, which had a good agreement with the results of the micro-Vickers hardness test.
Investigation in Rheocasting-Rolling for Semi-Solid Magnesium Alloy Used by Slope
Authors: Zhang Ying , Ma Qiang , Xie Shui Sheng , Geng Mao Peng , Xu Jin Hua , Guo Hong Min , Zhao Hai Bo
Published: November 2010

The experiment of the rheocasting-rolling for semi-solid magnesium was carried out on the equipment made by ourselves in our laboratory. Semi-solid AZ91D magnesium slurry was prepared by cooling slope and the evolution of microstructure under different technological parameters such as pouring temperature, casting temperature, standing time, angle of slope and length of slope et al were studied. The results show that the technological parameters have great influence on the microstructure of the semi-solid magnesium slurry. The results show that the optimum parameters of slope method were: pouring temperature 630 degrees；angle of slope 60°；length of slope 0.570m.
Multi-Scale Finite Element Method and its Application
Authors: Li Cui Yu , Zhang Xiao Tao
Published: November 2010

In order to improve the computing precision and computing efficiency of strength of woven composite material, the strength of woven composite material based on multi-scale finite element method (MsFEM) is simulated. The periodical boundary conditions are applied to the finite element method analyses to ensure stress continuous and strain continuous on boundary surfaces. The method can efficiently capture the large scale behavior of the solution without resolving all the small scale features by constructing the multi-scale finite element base functions that are adaptive to the local property of the differential operator. The characteristic difference between MsFEM and the conventional finite element method is attributed to base function. The applications demonstrate that the advantages of the multi-scale finite element method for numerical simulation of strength problem of woven composite material, i.e. significantly reducing computational efforts, and improving the accuracy of the solutions.
Modelling of Cyclic Plasticity and Viscoplasticity of a Nimonic Alloy 75
Authors: Zhan Zhi Lan , Liu Gao Ping , Chen Xuechao
Published: November 2010

Cyclic plasticity and viscoplasticity of a nickel-chromium alloy have been described using the Chaboche unified constitutive model. Experiments have been developed to obtain the full cyclic stress-strain and stress relaxation data at 450°C. A step-by-step method has been used to obtain the initial material parameters, while a non-linear least-square approach has been used to obtain the optimised material parameters. Satisfactory results have been obtained for the simulation of the transient and steady state cyclic stress-strain and stress relaxation behavior.
The Preparation of Sludge-Based Activated Carbon and Its Physical and Chemical Characteristics
Authors: Jiang Zhu Wu , Kang Kai , Xu Xiao Ming , Zhang Ya Lei , Wang Xue Jiang
Published: November 2010

In this article, the sludge-based activated carbon was prepared by the sewage sludge from the municipal wastewater treatment plants with ZnCl2 as the activator. The concentration of the activator was 30% and the pyrolysis temperature and duration were 500°C and 1 hour, respectively. The yield of sludge-based activated carbon was 30.14% with 4.66% ash. Under the best preparation condition, carbon content would be highest and the pore structure would be clear. The sludge-based activated carbon was mainly composed of mesopores. The main adsorption peaks of the sludge-based activated carbon were C-O-C (1078.3 cm-1), C=C（1568.7 cm-1）and –OH（3190.9 cm-1）groups.
The Effect of Temperature on the Surface Chemistry of Aluminum Alloy P-Ni Alloy Plating Quality
Authors: Chang Qing Hua , Zhi Er Hui , Wu Xu Ping , Han Jian , Chen Yan Fang
Published: November 2010

In aluminum alloy chemical plating process, temperature is one of the most important factors which directly affect the coating speed and quality. With the change of temperature with speed, so temperature is an important factor which affect the deposition speed. Therefore, to measure and study the influence on temperature to the quality of coating and plating speed is of important theoretical and practical significance. Using scanning electron observe the surface morphology of coating. Spectrum analyzer detects the surface content of Ni- P; then corrosion resistance of coating is detected, and thus the optimum temperature is determined.
Microstructure and Mechanical Properties of Ti-6Al-Mo-Fe Alloy Prepared by Powder Metallurgy
Authors: Wang Tian Guo , Qin Qun , Zhou Dong Jian
Published: November 2010

Ti-6Al-Mo-Fe alloys were prepared by blended elemental powder metallurgy process. In this paper, the mechanical properties and microstructure of Ti-6Al-Mo-Fe alloys sintered from the powders ball-milled for various periods of time were investigated by means of contrition behavior testing, X-ray diffraction, scanning electron microscopy. With an increase in ball milling time form 1h to 10h, the microstructure evolved into a fine β phase within the α matrix. For the Ti-6Al-Mo-Fe alloy, the yield strength and elongation increase as the milling time is prolonged. It was found that the bulk alloys made from the powders ball milled for 6 h exhibited relatively high elongation of 17.8% and high yield strength of 914 MPa.
Comparative Study on Data Editing Techniques for Fatigue Time Series Signals
Authors: Mohd Nopiah Zulkifli , Abdullah Shahrum , Baharin Mohd Noor , Putra T.E. , Sahadan S.N. , Willis K.O.
Published: November 2010

This paper presents the comparative study on three types of fatigue data editing technique for summarising long records of fatigue data. Two of techniques were developed based on timefrequency domain (continous wavelet and discrete wavelet) and another one technique was developed based on time domain. These three techniques are used to extract fatigue damaging events in the record that cause the majority of fatigue damage, whilst preserving the load cycle sequence in the data. The objective of this study is to observe the capability of each technique in summarising long records of fatigue data. For the purpose of this study, two set of nonstationary data that exhibits random behaviour was used. This random data was measured in microstrain unit on the SAE1045 material that were used as a lower suspension arm of a car. Experimentally, the data was collected for 60 seconds at sampling rate of 500Hz, which gave 30, 000 discrete data points. The result of the study indicates that all techniques are applicable in detecting and extracts fatigue damaging events that exist in the fatigue data. However, it was found that continous wavelet can extract the data better than the other technique based the shorten signals, retention of damage and statistical parameter.
Evolution of Recrystallization Microtexture of Cold-Rolling Low Carbon Sheet Steel Based on CSP during Batch Annealing
Authors: Jin Zi Li , Ren Hui Ping , Li De Gang , Yan Bo
Published: November 2010

The mechanism responsible for the formation of recrystallization texture is still disputed although recrystallization texture has long been a subject of research. This is mainly related to the complexity of recrystallization itself .The mechanism of recrystallization microtexture Cold-rolling low carbon sheet steel based on CSP was investigated by the electron back scatter diffraction(EBSD) was investigated. In addition, the origin of nuclei with specific orientations was studied. The results showed that the formation of recrystallization texture is explained by oriented nucleation and the nucleis show around 50% frequency of 15–60°misorientation with their surrounding deformed matrices. Deformed γ-fibre texture components increase more rapidly during the early stage of recrystallization. In contrast, the deformed α-fibre components, such as {001}<110> components disappear rather rapidly early stage of recrystallization and {112}<110> components increases rapidly late stage of recrystallization and grains growth. By microcosmic orientation distribution analyse find that the new {011}<100> grains are nucleated within shear bands in the deformed {111}<112> grains, New {111}<112> grains are nucleated within deformed {111}<110> grains and new {111}<110> grains originated in the deformed {111}<112> grains .
Kinetics of Mg2Sn Synthesis Reaction under Isothermal Condition
Authors: Wu Yu Feng , Du Wen Bo , Wang Zhao Hui , Zuo Tie Yong
Published: November 2010

The kinetics of Mg2Sn synthesis reaction was studied under isothermal condition in the present paper. Results indicated that the isothermal reaction of Mg2Sn was controlled by two reactive mechanisms: the nucleation and growth control in the first stage corresponding to the Avrami exponent, m≈3, and the phase boundary control in the second stage corresponding to m≈1.1. The reactive activation energy (Ea ) for the two stages was 293.6 kJ·mol-1 and 358.1 kJ·mol-1, respectively. The microstructural evolution in Mg2Sn synthesis process was in good agreement with the two reactive mechanisms.
Study on Semi-Solid Magnesium Alloy Produced by Mechanical Stirring
Authors: Zhou Bing Feng , Yan Hong
Published: November 2010

Semi-solid magnesium alloy slurry was produced by a newly self-developed mechanical stirring machine in order to prepare continuous semi-solid slurry. The changing principle of semi-solid microstructure was studied under different conditions—the changing of temperature, stirring rate, cooling rate and stirring time. It was showed that the lower the temperature of slurry, the higher the stirring rate, the longer the stirring time and the faster the cooling rate, the grain will be smaller and more evenly rounded. When the stirring speed and temperature are the same, better semi-solid spherical grains can be gained by increasing the stirring time. At the same stirring temperature and higher stirring speed, semi-solid spherical particles are smaller, rounder and more evenly; at a low stirring speed, we can't get ideal semi-solid spherical grains even if we increase the stirring time. The ideal technological parameters of semi-solid AZ61 alloy produced with no-dendritic structure were recommended to be 600°C～605°C (stirring end temperature) 、3min～ 5min(stirring time) and 500r/min(stirring rate). Compared with conventional casting alloy, semi-solid alloy mechanical properties were greatly improved. The non-dendrite semi-solid forming mechanism was studied; mechanical stirring semi-solid non-dendritic formation was the result of a variety of factors, the key cause is mechanical shear stress.
Macroscopic and Mesoscopic Large Deformation Measurement Methods for Metal Materials
Authors: Liu Cai Ping , Duan Qing Quan
Published: November 2010

The stress-strain curve in the large plastic deformation process is always not available due to the strain gauge deficiencies in large deformation measurement. Considering this problem, digital marker identification technique is used to measure large deformation of Steel Q235 with images taken by with charge-coupled device. Then together with the deformation measured by traditional stain gauge at small deformation stage, the total stress and strain curve is obtained at macroscale. The mesoscopic deformation is measured by a material testing system assembled with scanning electronic microscope. The images from the initial stage to the rupture stage are captured synchronously. What’s more, using the grid method, the strain and rotation in rational mechanics is analyzed.
Very High Cycle Fatigue Behavior of Carbon Manganese Steels
Authors: Xue Hong Qian , Wagner Danièle
Published: November 2010

An ultrasonic fatigue testing system capable of operating at temperatures at 250 has been introduce to study the fatigue behavior of carbon manganese steels (A42 and A48) and loading frequency of approximately 20 kHz. Endurance limit results were comparable to those generated at room temperature to determine the effect of temperature. Scanning electron microscopy was then used to determine the initiation sites and the failure mechanisms. Initial results indicate that fatigue strength decrease a little at 250 , interior inclusions were the major microstructural feature responsible for crack initiation in the alloy.
Effect of Electromagnetic Vibration on Microstructures of Semi-Continuous Casting AZ80 Magnesium Alloy Billet
Authors: Zhang Zhi Qiang , Le Qi Chi , Cui Jian Zhong , Guo Shi Jie
Published: November 2010

Microstructures and macrosegregation of AZ80 magnesium alloy billets cast with and without the electromagnetic vibration were investigated. Compared with the conventional DC casting, microstructures of the billet have been greatly refined and the macrosegregation had been effectively reduced in electromagnetic vibration casting conditions. Increasing the electromagnetic vibration intensity, including both the stationary magnetic field and alternating magnetic field, leads to finer grains and more uniform distribution of solute elements in the billet.
Quantifying Partially-Carbonated Profiles of Concrete with Low Water/Binder Ratio Exposed to Natural Carbonation
Authors: Ba Ming Fang , Qian Chun Xiang
Published: November 2010

Thermo-gravimetric analysis (TGA) and Infrared Spectrum (IR) analysis were adopted to quantify the partially-carbonated profiles of concrete segment exposed to long-time natural carbonation. The results showed that the residual Ca(OH)2 content could be calculated by TGA, and the CaCO3 content formed by carbonation could also be quantified by IR. Thus the partial-carbonation profile illustrated by residual Ca(OH)2 distribution was lower than that by CaCO3 distribution, which indicates Ca(OH)2 and C-S-H gel were carbonated. Furthermore, the carbonation degree of concrete segment was lower than that of specimen because of dimension effect, which suggested that the small specimen could be used to assess carbonation related durability of concrete structures with good reliability.
Preperation of Ceramic Coatings on Ti Alloy by Surface Nanocrystallization/Micro-Arc Oxidation
Authors: Zhang Jin Xue , Hao Guo Dong
Published: November 2010

Nanostructured surface layer was produced on Ti-6Al-4V alloy by surface mechanical attrition treatment(SMAT) technique, and the composite ceramic coatings of surface nanocrystallization/micro-arc oxidation(SNC/MAO) were prepared on the nanocrystallized surface of Ti-6Al-4V alloy by pulsed single-polar micro-arc oxidation in NaAlO2 solution. XRD, SEM and TEM techniques were used to investigate the phase and surface morphology of ceramic coatings and the influences on the surface state of the alloys. Meantime, the mechanical properties of Ti alloys were measured by tensile test. The results show that after the SMAT treatment for a short period of time, the surface layer was refined into ultrafine grains. The influences of the SMAT technique on the surface morphology of the ceramic coatings were also studied. The ceramic coatings are mainly composed of Al2TiO5, more compact and less porous than those untreated. The mechanical properties of Ti-6Al-4V alloy by SMAT technique are improved, compared with those untreated by SMAT technique.
Effect of Ca, Sc and Er Microalloying on the Microstructure and Properties of AZ61 Alloys by Electromagnetic Casting
Authors: Ren Zheng , Song Jian Min , Zhu Xiu Rong , Zhou Gu Xin , Zhao Xin Bing , Zhang Xing Guo
Published: November 2010

The effect of Ca, Sc and Er microalloying on the microstructure and properties of AZ61 alloys by electromagnetic casting are investigated. Experimental results show that an addition of Ca, Sc and Er refine the grains and compounds of AZ61 alloy. Mg17-xCaxAl12 phase are obtained after Ca addition. When the Ca, Sc and Er added in AZ61 alloy, some new phase contain Ca, Sc and Er are appeared. The tensile properties are improved as a result of grains and compounds refinement arter Ca, Sc and Er microalloying.
Fatigue Crack Propagation at Negative Stress Ratio in 2A12 Aluminum Alloy
Authors: Sha Yu , Bai Shi Gang , Zhang Jia Zhen
Published: November 2010

Fatigue crack propagation tests in the Paris region were performed in order to get compressive loading effect on fatigue crack growth at negative stress ratio (R) in 2A12 aluminum alloy. The results of the tests showed that the effect of the compressive loading part of the applied stress cycle on fatigue crack growth rate da/dN in 2A12 aluminum alloy at negative stress ratio can not be omitted. The fatigue crack growth rate at R<0 was more than that at R>0 under the same range of stress intensity factor Kmax. The da/dN is the function of Kmax and stress ratio R. The promoting effect has an increase trend with the increase of the absolute value of the negative stress ratio R. Then a model involved compressive loading effect on fatigue crack propagation at negative stress was obtained. The model has been obtained good agreements with the experimental data.
Dynamic Recrystallization Behavior of Microalloyed 3.5Ni Steel
Authors: Li Jian Hua , Xi Tian Hui , Chen Xiao , Wu Kai Ming
Published: November 2010

Both the critical conditions and evolution of dynamic recrystallization behavior for a Nb-Ti microalloyed 3.5Ni steel were carried out by isothermal compression deformation on a Gleeble-3500 thermal simulator. Results show that the critical conditions of dynamic recrystallization behavior deformation of 30 % at 1050 °C, and the accumulative deformation for full dynamic recrystallization is 50 % at a strain rate of 1 /s. Accordingly, proposals on how to roll 3.5Ni steel were made.
Shape Recoverability Mechanism of "PTT Shape Memory Fabric"
Authors: Zhao Li Huan , Wang Fu Mei
Published: November 2010

"Poly(trimethylene terephthalate) (PTT) shape memory fabrics" have excellent shape recoverability, whose clothes are easy to take care. In order to study the mechanism of “PTT shape memory fabric"’s shape recoverability, test of removing yarns from fabrics and comparing their crease recoveries with those of fabrics was designed. Results showed that crease recovery ratios of "PTT shape memory fabrics" were about 36%, while those of yarns removed from them were nearly 80%. Therefore, the results revealed that PTT yarns had good recoverability, however, the high inter-filament frictional forces in the fabric offerring by tight weave structures prevented PTT yarns from recovering. When the applied force was large enough to overcome frictions between filaments, the fabric gained sufficient mobility, coupled with PTT filaments’ excellent elastic recovery properties, and gave excellent fabric crease recovery. Moreover, new test method was designed independently to test different kinds of yarns’ crease recovery angles, results had proved once more PTT yarns had good elastic recovery, and their crease recovery ratios were close those of wool yarns, while the crease recovery of natural silk and cotton were the worst.
Oxidation Behaviors of DO3 Type Fe3Si Based Intermetallics at 900°C
Authors: Zhou Qi , Jia Jian Gang , Zhao Hong Shun , Zhang Xin Min
Published: November 2010

In the present work, intermetallics Fe3Si and Fe3 (Si1-xAlx) (x=0.33, 0.67, 0.80) produced by arc melting, were evaluated regarding the oxidation at 900°C in air. The test preformed was the isothermal and cyclic oxidation. The microstructures of oxide films were analyzed by XRD, SEM, EDS, EPMA. The result showed that the four kinds of intermetallics had good oxidation resistance at 900°C.The addition of Al element can increase the oxidation resistance of Fe3Si based intermetallics. The oxidation kinetics of the four intermetallics follows the rule of the parabola. The main oxidation product of Fe3Si is SiO2.The kinetics of oxidation reaction is mainly controlled by Si diffusion. The oxidation product of three Al alloying Fe3Si based intermetallics is Al oxide. Al moves outward from the substrate to form a protective oxide film which restrained the diffusion of Si and Fe outward.
Core Courses for Undergraduate Students in Materials Science and Engineering
Authors: Wang Zhan Yong , Xu Jia Yue , Chen Hui Fen , Fang Yong Zheng , Liu Xiao Rong
Published: November 2010

As a professional with strong theoretical and practical in a new college, the guidance major-materials science and engineering involves extremely broad field. Our reform ideas and practices are only to training science-based applied talents possessing engineering capabilities. Facing the new situation on the demand for materials engineering personnel, we reform curriculum and teaching to get rid of the drawbacks of the original content and build the professional training program with the characteristics and course system.
Fabrication of Thermo-Conductivity Film Using Anodic Aluminum Oxide Template and Silver Nanowires
Authors: Chen Chien Chon , Chang Shao Fu , Kao Mann Juin , Jheng Wern Dare , Hao Wang Shing
Published: November 2010

This paper discussed fabrication of a very low thermal resistance of thermal interface membrane (TIM). It is assumed that anodic aluminum oxide (AAO) template with silver nanowires inside can function very well as TIM. The TIM was made of well-aligned silver nanowires are expected to reduce the thermal resistance between the heat sink and the electronic device, a chip for example. This work also calculated the pore density, surface area, and porosity of AAO, and thermal conductivity values of AAO with different diameter nanowires inside.
The Mechanical Properties of PSA Fibers after Corrosion
Authors: Yuan Xin Yan , Shen Heng Gen , Wang Zhen Hua , Hou Wei Li
Published: November 2010

In order to reveal the influence of acidic gas SO2 and CaO etc alkali substances which are contained in industrial furnaces smoke to the strength of PSA fiber, tests are made in different acid and alkali conditions, and the changes of its surface morphology were observed by scanning electron microscope (SEM). The results show that: PSA has better acid corrosion resistance than alkali corrosion resistance. Its acid corrosion resistance is similar to the domestic aramid. PSA is better than Nomex in the concentration of 5% H2SO4. Its alkali corrosion resistance is worse than domestic aramid. The retention rate of breaking strength drop to 60.80% and 69.52% respectively after treated in the concentration of 5% H2SO4 for 48 hours and in the concentration of 5% NaOH for 4 hours. The elongation rate decline to 68.14% and 40.22% respectively, and the elongation rate fell to 68.14% and 40.22% respectively. Therefore, the PSA must be dealt against corrosion when used in strong acid or alkali environment.
Research of Micromechanism on Residual Stress in Aluminum Alloy Thick Plate
Authors: Liao Kai , Jing Xin Xing , Zhou Ya , Wei De Qiang
Published: November 2010

The research of micromechanism of stress evolvement is presented by analyzing fluctuation and change of surface stress in aluminum alloy thick plate with X-ray diffraction(XRD). From the micro view, a model of “rotation looping and shearing grain” was proposed to analyze and discuss the inhomogeneous distribution of micro-stress in location area, due to inhomogeneity of organization in material. The results present that the inhomogeneity of plastic deformation is direct cause lead to residual stress in plate, and complication of micro-stress distribution results from non-uniformity of organization.
Research on Cryogenic Properties of Different Fiber Asphalts and Mixtures
Authors: Liu Kai , Zhang Wei Hua , Wang Fang
Published: November 2010

From microstructure and technical performance of different fibers, the variation and influence of the different fibers’ properties and parameters on cryogenic properties of matrix asphalt and asphalt mixture were researched and evaluated through BBR and cryogenic trabecular bending tests. Research shows that: the addition of fibers makes the matrix asphalt’s low temperature creep stiffness S increases, creep slope m decreases, namely the matrix asphalt cryogenic flexibility and stress relaxation ability are weakened; cryogenic anti-cracking ability of asphalt mixture is significantly improved through adding different fibers, the order of improving effectiveness: Dolanit AS fiber> ARBOCEL lignin fiber> Basalt fiber; while asphalt content is constant, with the increase of fiber content, the mixture maximum bending strain, strength, deformation of mixture firstly increase and then decrease, the optimal asphalt content of asphalt mixtures and optimal fiber content of three fibers are identified according to the above three indicators’ maximum. Research points out the existed problems that are scope of application and evaluation indicators in BBR test of SHARP, optimal asphalt and fiber content are fully recommended, it provides scientific guidance and practical foundation for actual project.
The Fuzzy Judgment for the Wearing Life Distrituion of the Rolling Bearing
Authors: Xu Shi Lian , Pan Qi Ying , Hu Gui Ping , Xu Ren Ping
Published: November 2010

the wearing of the rolling bearing is actually associated with both randomness and fuzziness. In this paper, we analyze the fuzziness of the experimental data of the wearing life of the rolling bearing and discuss its fuzzy subsets, membership function and fuzzy identification. We take the wearing life of the 102 rolling bearing for example, study the normal fuzzy set and three-parameter Weibull fuzzy set and conduct the identification for the probability distribution. In particular, we also develop an innovative method to identify the experimental data of the wearing life of the rolling bearing.
Effect of Thermohydrogen Treatment Temperature on Machinability of Ti6Al4V Alloy
Authors: Yu Chao , Guo Jian Ye , Zhang Yan Li , Li Jing Kui
Published: November 2010

The temperature of thermohydrogen treatment for the testing workpieces respectively was 650°C,750°C,850°C. By turning testing workpieces of different hydrogen content Ti6Al4V alloy, measuring cutting force and surface roughness as well as observing chip morphology, the effect of themohydrogen treatment temperature on machinability of Ti6Al4V alloy has been studied. Results of this experiment indicate that machinability of Ti6Al4V alloy improves with increasing the temperature of thermohydrogen treatment at the range of experimental temperature.
Research on Internal Stress in Electroplated Cu Films on Fe Substrates and Ni Substrates - Based on Electron Theory
Authors: Ren Feng Zhang , Zhang Fa Xiang , Yin Li Tao , Zhao Shi Yang , Tian Bao Hong , Su Juan Hua
Published: November 2010

Electroplating was employed to prepare Cu films on Fe substrates and Ni substrates. The average internal stresses in Cu films were measured in situ by cantilever beam test. The distribution of the internal stresses in Cu films was investigated. The results show that the average internal stresses and the distributed internal stresses in Cu films decrease abruptly with the increase of film thickness when the films are thinner. The interfacial stresses in Cu films are very large and growth stresses are very small. The average internal stresses in Cu films, which were caused by the adjustment of the electron densities at either side of the interface, were calculated roughly using a modified Thomas–Feimi–Dirac electron theory. For the same substrate and the same film, the theoretical value of the average internal stress in film is about equal to the experimental value. It shows that the theoretical calculation model of internal stress is of accuracy.
Ageing Behaviour of a Cu-Cr-Zr Alloy under an Imposed Electric Current
Authors: Wang Zhi Qiang , Zhong Yun Bo , Deng Kang , Ren Zhong Ming
Published: November 2010

A direct current was imposed during the ageing treatment of cold worked Cu-Cr-Zr alloys. The effect of increasing current density and ageing time on the electrical conductivity and microhardness has been investigated. The electrical conductivity was found to increase by about 22% IACS to a maximum value of 90% IACS. Furthermore, the microhardness increased by 21 HV up to 176 HV. A number of Cr precipitates and Cr-rich clusters were observed after the ageing treatment with direct current. The direct current was found to significantly enhance the efficiency of precipitation which is most probably due to the electron wind force and the electromigration-induced mass transport.
Research on Damping of Foamed Al Composite Filled Epoxy Resin in the Holes
Authors: Yu Ying Hua , Wu Xue Na , Xu Ping
Published: November 2010

Damping of foamed Al composite filled epoxy resin in the holes is researched by experimental and theoretical analysis. The results are showed that foamed Al damping can be improved by Filling epoxy resin in the holes, and with porosity increasing or diameter decreasing, the composite’s Damping is increased, but the change of damping with frequency is non- monotone function. The results can provide reference for optimization and application of the composite.
The Influence of Complexing Agent to the Function of Electroless Plating of P-Ni Alloy on Magnesium Alloy
Authors: Chen Yan Fang , Yu Xue Tao , Qi Yan Jie , Ma Ming Yue , Chang Qing Hua
Published: November 2010

To improve the corrosion resistance and wear resistance of AZ31B magnesium alloy, in this dissertation, we use the method making AZ31B magnesium alloy as the matrix to make coating on the way of electroless plating nickel-phosphor directly. In this study, we make experiments on the influence of concentration of complexing agent in electroplating to electroless plating on the surface of magnesium alloy. We utilize the scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and the detection of corrosion resistance etc. To analyze the morphology, composition and corrosion resistance of coating. We come to a conclusion that the reaction is at the soonest when we adopt sodium citrate as buffering agent and its density is10ml/L., meanwhile, the coating particle is tiny and is well-knit with matrix. What’s more, phosphorus contents are maximum and the corrosion resistance is greatest.
Micromechanical Strength of Particle in Composite Ceramic with Partial Debonding Interphase
Authors: Ni Xin Hua , Liu Xie Quan , Han Bao Hong , Zhong Guo Hui , Zhao Lei
Published: November 2010

The four-phase model is used to predict the strength of particles in composite ceramic with partial debonding interphase. Firstly the external strain of three-phase cell is determined. Based on the disturbance strain tensor of three-phase cell, the micromechanical stress field of the particle is obtained. Then based on the generalized thermodynamic force of the particle in damage process, the damage equivalent stress of the particle in the three-phase cell can be calculated. As the damage equivalent stress is equal to the ultimate stress of the particle, the micromechanical strength of particles in composite ceramic with partial debonding interphase is obtained. Finally, For Al2O3-ZrO2 composite ceramic with partial debonding interphase, the variations of the micromechanical strength of particles for different orientation angle and different particle diameter are analyzed. The result shows that the micromechanical strength of particles is determined by the 50° orientation three phase cell, and has obvious size dependence. The micromechanical strength of particle will decrease when the particle diameter increase.
Effect of the Interlamellar Spacing on Mechanical Properties of SWRS82B Wire Rod before and after Drawing
Authors: Liang Yi Long , Xiang Song , Yang Ming , Liang Yu , Yang Xiao Di
Published: November 2010

The mechanical properties and microstructure of SWRS82B wire rods and drawn wire were studied. Wire rods were austenitized at 850°C~900°C and held at 500°C~600°C. The results show that the finer interlamellar spacing results in the higher yield strength, tensile strength and reduction of area of the wire rod. Moreover, the finer interlamellar spacing does result in the higher yield strength of the drawn wire too.
Modified PP Fibers Reinforced Cement Mortar
Authors: Li Bao Jia , Li Guo Zhong , Ning Chao
Published: November 2010

Effect of different dosages of PP fibers on cement mortar were studied. PP fibers were modified by Silane Coupling Agent, and the strength of cement mortar was tested. The results show that, compared with unmodified PP fibers, the modified PP fibers can improve the strength of cement mortar more effectively. The microstructure of PP fibers reinforced cement mortar was analyzed by SEM, and the mechanism of modified PP fibers reinforced cement mortar was discussed preliminarily.
An Analytical Model of Wool Crimp
Authors: Liu Hua Wu , Bryson Warren G. , Wang Zhen Yun , Xu Ping
Published: November 2010

A three-component analytical model for single fibre curvature is developed in terms of the axial contractions, elastic moduli and geometrical properties of wool fibre cells. The elastic moduli of wool cells and single fibre curvature of selected Romney wools are measured. Using axial contraction data from the literature, the mean single fibre curvature is computed and compared with the measured mean value. The simulation is about the same as the measured value when the para- to orthocontraction ratio is 1.7:1.
Impact Behaviors of Flax/Polypropylene Weft Knitted Composites
Authors: Li Hong Xia , Liu Li , Zhang Jian Ming , Liu Ya Nan , Huang Gu
Published: November 2010

For developing the environmentally protective civil textile composites with better impact behaviors, the impact test was made with flax/polypropylene weft knitting composites samples. The mechanisms of fiber reinforcing and fracture were discussed through examining the fracture photographs. This research shows that the samples have better impact behaviors when the volume fraction of flax fiber is about 50%，the amount of layers is 8, and the sinker depth of the flax/pp knitted perform is 9.