bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Researches of Co-Cr Alloys Powders Manufactured by Sintering Process DMLS and Ni-Cr Alloys Used in Dentistry
Authors: Băilă Diana Irinel
Published: August 2015

The purpose of this study was to evaluate the chemical and metallurgical aspects, mechanical properties and hardness of the Co-Cr alloy powders manufactured by sintering process DMLS and compared with Ni-Cr alloys used for personalized dental crowns.In dentistry are develop new methods to obtain personalized dental crowns quickly, the cost is not expensive and is identically with the dental scan realized by dentist. DMLS sintering manufacturing is a new method who permits to realize in the same day the dental crowns with the first control.Powders of Co-Cr alloys presents good sintered properties, good mechanical properties and the sintered probes don’t present tensile strength in the material after DMLS process.
Effect of Cerium Addition and Cooling Rate on Microstructure of ADC12 Eutectic Cast Alloy
Authors: Ahmad Roslee , Asmael M.B.A.
Published: August 2015

This research was to determine the effect of Cerium and cooling rate on the microstructure of eutectic Al-11Si-Cu-Mg cast alloy. The Cerium was added to produce Al-11Si-Cu-Mg-1.5Ce alloys. The microstructure was characterized by optical microscope. The Si structure was modified with the increase of the cooling rate, where smaller area was achieved. Ce formed rich intermetallic phase, such as Al-Si-Ce.
Synthesis and Surface Modification of ZnO Nanorods Arrays
Authors: Akram Muhammad Aftab , Javed Sofia , Mujahid Mohammad
Published: August 2015

Synthesis of 0ne dimensional (1-D) vertically aligned nanostructures of ZnO are reported to act as scaffold for conversion to or coating of other semiconducting compositions. Surface of ZnO is converted to ZnSe by anion exchange and results in formation of ZnO/ZnSe core/shell nanorods. ZnSe is further converted to CuSe by cation exchange method to fabricate ZnO/CuSe core/shell nanorods. ZnO nanorods or core/shell compositions are decorated with absorber nanoparticles of CZTSe & CIGSe for the fabrications of photoanodes of nanowire solar cells. 1-D or core/shell Nanostructures are characterized by scanning electron microscope for morphological analysis and structural confirmations are made by XRD and Raman spectroscopy.
Study of Mechanical Properties of Stainless Steel Oil Spill Plate on UG Finite Element Method
Authors: Li Rong Long , Hu Fei
Published: August 2015

The oil spill plate is a thin-walled type of mechanical model [1] ,the structure of stainless steel oil spill plate is analyzed precisely by using UG finite element method, it is concluded the structure displacement and stress changes at the bottom of the oil spill plate of the board structure and determine oil spill plate meets the production requirements or not. The conclusion provides theoretical support for the production practice.
Effect of Different Operating Temperatures on Mechanical Properties of Several Rolled Aluminum Alloys
Authors: Zhu Wei Bo , Jiang Xian Quan , Li Quan , Wang Si Ya
Published: August 2015

The five kinds of 1100, 1050, 1108, 8079 and 8079H alloy sheets have been prepared by melting, casting and rolling process and tensile strength and elongation of alloys have been tested at room temperature, 100°C, 200°C, 300 °C. For provide a reference of the mechanical properties for the applications of these alloys. It was indicated that the mechanical properties of alloys were significantly different at different operating temperatures, the overall trend is that the tensile strength (σb) of the alloys decreased significantly and the breaking elongation (εb) of the alloys remarkably increased with the increase of the testing temperatures. The tensile strength of the alloys are about 30MPa at 300°C, so the operating temperature of the alloys should be controlled below 300°C.
Research on Heavy-Duty Coating Protection System of Magnesium Alloy
Authors: Yan Ru Tang , Li Yuan Yuan , She Chun Wei , Li Hua Geng , Li Hua Pan
Published: August 2015

The poor corrosion resistance of magnesium alloys become the bottleneck restricting its development. Based on micro-arc oxidation (MAO) technology and the characteristics of fluorocarbon coating the surface of magnesium alloy build a high corrosion protection system, namely: Based on micro-arc oxidation coating fluorocarbon coatings. The formation of the composite coating through the resistance to ageing test through the resistance to ageing test, acid and alkali experiment and salt spray test results show the excellent corrosion resistance performance. Among them, the resistance to salt spray test time can reach 1500 h, which breaks the bottleneck of magnesium alloy corrosion resistance of 1000 h.
A Numerical Study on Stir Casting Process in a Metal Matrix Composite Using CFD Approach
Authors: George Joseph , Janardhanan Sheeja , Sijo T.M.
Published: August 2015

This work brings out the numerical simulation of the stir casting technique for aluminium silicon carbide Metal Matrix Composite (MMC) in a closed crucible and the effect of the blade geometry and rotational velocity on solidification of the metal matrix composite has been predictedusing Computational Fluid Dynamics (CFD) approach. The material used in the crucible is silicon carbide in aluminiummetal matrix. Geometric modelling and meshing have been carried out using ANSYS ICEM CFD. Computer simulations have been carried using the commercial CFD package, ANSYS FLUENT. The calculations used 2-D discrete phase, solidification and melting model and enthalpy method. Mushy state mixing, indicative of the solidification patterns have been studied to predict the most suitable ratio of crucible to blade dimensions and speed of stirring to obtain the most uniform type of solidification which in turn induces some enhanced mechanical properties to the casting.
Sulfate Ion Influence of LiNi1/3Co1/3Mn1/3O2 as Cathode Material for Lithium-Ion Batteries
Authors: Dai Jian Feng , Liu Ji Fei , Fu Bi
Published: August 2015

The residue sulfate ions (SO42-) occurs in an adsorption and complex salt manner which are significant influence the electrochemical properties of LiNi1/3Co1/3Mn1/3O2 as cathodes materials for lithium-ion batteries. Compare with different SO42- concentration electrochemical performance reveals that low SO42- concentration (0.28%) demonstrated a better charge/discharge cycle performance than the high SO42- concentration (0.48%) of LiNi1/3Co1/3Mn1/3O2, it maintains a capacity of 148.9 mAh·g−1 with a coulomb efficient of 91 % after 100 cycles which superior to the SO42- concentration (0.48%) circulation coulomb efficient of 87%, respectively.
Surface Roughness Analysis of Carbon/Glass Hybrid Polymer Composites in Drilling Process Based on Taguchi and Response Surface Methodology
Authors: Tan Chye Lih , Azmi Azwan Iskandar , Muhammad Noorhafiza
Published: August 2015

Drilling is an essential secondary process for near net-shape of hybrid composite as to achieve the required dimensional tolerances prior to final application. Dimensional tolerance is often influenced by the surface integrity or surface roughness of the workpart. Thus, this paper aims to employ the Taguchi and response surface methodologies in minimizing the surface roughness of drilled carbon-glass hybrid fibre reinforced polymer (CGCG) using tungsten carbide, K20 drill bits. The effects of spindle speed, feed rate and tool geometry on surface roughness were evaluated and optimum cutting conditions for minimizing the aforementioned response was determined. Subsequently, response surface methodology (RSM) was utilised in finding the empirical relationships between experimental parameters and surface roughness based on the Taguchi results. The experimental analyses reveal that surface roughness is greatly influenced by feed rate and tool geometry rather than the spindle speed. This is due to the increment of feed that attributed to the increased strain rate and hence, deteriorated the surface roughness of the hybrid composite. The predicted results (via regression model) and theoretical results (via additivity law) were in good agreement with experiment results. This indicates that the regression model from response surface methodology (RSM) can be used to predict the surface roughness in machining of CGCG hybrid composite.
Evaluation of Two Different Energy Inputs for Deposition of Stellite 6 by Laser Cladding on a Martensitic Stainless Steel Substrate
Authors: Kusmoko Alain , Dunne Druce , Li Hui Jun
Published: August 2015

Stellite 6 was deposited by laser cladding on a martensitic stainless steel substrate with energy inputs of 1 kW (MSS-1) and 1.8 kW (MSS-1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was assessed using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the MSS steel substrate with the lower heat input (MSS-1). Further, the Stellite coating for MSS-1 was significantly harder than that obtained for MSS-1.8. The wear test results indicated that the weight loss for MSS-1 was much lower than for MSS-1.8. It is concluded that the lower hardness of the coating for MSS-1.8, markedly reduced the wear resistance of the Stellite 6 coating.
Porosity and Microstructure Phase of Self Compacting Concrete Using Sea Water as Mixing Water and Curing
Authors: Erniati Erniati , Tjaronge M.W. , Sampebulu Victor , Djamaluddin Rudy
Published: August 2015

In Indonesia, several regions have a minimum quantity or none of fresh water. Self Compacting Concrete (SCC) has a dense microstructure. Knowledge about the microstructure and properties of the individual components of concrete have a relationship that is useful for controlling the behavior of concrete. Porosity and microstructure SCC using sea water as mixing water and curing water discussed in this paper. The results showed the higher the compressive strength of SCC sea water is getting smaller porosity. Porosity on the SCC decreases with increasing quantities of microstructure phase tobermorite (CSH), portlandite (CH), Friedel's salt and ettringite.
Fibre Reinforced Concrete Class Control via Fib Model Code 2010 Approach
Authors: Rusanov Vladimir E.
Published: August 2015

Fibre reinforced concrete (FRC) has wide spectrum of advantages in tunnelling. Post-cracking behaviour of FRC wasn’t taken into account by Russian engineers while structural design led to underestimation of material abilities. New approach is based on fib Model Code 2010, which provides residual tensile strength Class of FRC. Research Center “FRC” (http://rcfrc.com/) carried out tests with specimens of different types of FRC, which supported by Russian Foundation for Basic Research. Research involved different specimens – plain concrete and FRC with macro-synthetic fibre of different dosage and types. The results showed the efficiency of each type of fibre. The Class of FRC was defined for each specimen series according to results.
Mechanical Performance of a Plate Made by RC and Repaired through SFRC Material
Authors: Dal Cin Alessandra , Massaria Lorenzo , Siviero Enzo
Published: August 2015

The aim of this study is to evaluate the influence of SFRC repairs of different thicknesses on the mechanical performance of RC slabs, especially with respect to the crack pattern and level of cracking load. To understand the influence of SFRC, in terms of performance and variation of cracking load after repairing, a comparison with a reinforced concrete slab without fiber reinforcement was made. The study shows also the mechanical characterization of SFRC through conventional testing, to evaluate compressive strength, fracture energy, tensile strength and toughness. Concerning the application of SFRC on the concrete slab surface, the bond was improved by removing a small amount of superficial material. Finally, the experimental results on cracks distribution, displacements and level of cracking load are shown.
Residual Mechanical Parameters of Masonry Exposed to Fire: A New Numerical Approach
Authors: Russo Salvatore , Sciarretta Francesca
Published: August 2015

The paper is part of a research that aims at investigating the relationship between fire and post-fire (i.e. residual) mechanical behaviour of masonry walls, paying attention to the possible exploitation of numerical tools for simplified approaches. The goal is to establish relationships between exposure severity under ISO834 conditions and decay in mechanical properties after exposure; the parameter of wall thickness is especially investigated, by choosing four different values (i.e. 12, 25, 38 and 51 cm). This is performed by means of FEM analysis with DIANA 9.4.4 software, simulating a standard ISO 834 fire resistance test followed by a mechanical compressive failure test on each investigated type of wall. The FE analyses’ outcomes allow to draw exponential expressions of the decay in compressive strength as a function of the exposure severity.
Choice between Retrofitting and Reconstruction of Buildings in Reinforced Concrete after an Earthquake
Authors: El Kechebour Boualem , Zeloum Hamoud
Published: August 2015

This study aims at presenting a methodology for the taking decision about the retrofit or the destruction of the damaged buildings by an earthquake. The proposition is founded on the damages caused by the seism of Boumerdes in Algeria, on 23 May 2003. This work can to help the authorities and owners to make a choice concerning the retrofit or the destruction of buildings and reconstruction.The analysis begins by the identification of the structural damages in the structures, then by the evaluation of costs of the reparations and the retrofit of all functions of the building. If the owner has contracted insurance, the amount of insurance is deducted. After this step, this cost is compared to the cost of the destroying of the old building and the rebuilding cost of a new similar building. The life duration of structure is integrated respectively for the retrofitted building and the build of a new equivalent building. The depreciation of capital according to the time of exploitation is calculated on the reference: fifty years for the new investments, and twenty-five years for the retrofitted buildings.The resolution of the problem uses the comparison between the cost of retrofit divided by twenty-five to which added the amount of insurance, and the cost of new equivalent construction divided by fifty to which added the amount of destruction. This approach gives a result according to retrofit, insurance, the equivalent new building and the depreciation of capital. The compilation of the actualized costs according to each zone permits to have a quick vision about the economical decision. The cost of the urban land component is not taken in account and the network is considered in good state.
Effect of Carbonation on the Sulfate Attack of Concrete Materials
Authors: Zhang Shi Ping , Zhao Bing Hua , Zong Lan
Published: August 2015

In this paper, experiments have been carried out to determine the effect of carbonation on the resistance of sulfate attack of concrete materials. The accelerated carbonate testing was used to prepare the carbonated specimens, and wetting-drying cycles were used to evaluate the resistance of sulfate attack. Results show that longer carbonate time leads to greater depth of carbonation, and fly ash may accelerate the carbonation of concrete materials. The loss of flexural strength was greater than that of compressive strength under the condition of sulfate attack. Carbonation is detrimental to the resistance of sulfate attack.
Influence of FRP-to-Concrete Gap Effect on Axial Strains of FRP-Confined Concrete Columns
Authors: Vincent Thomas , Ozbakkloglu Togay
Published: August 2015

This paper reports on an experimental investigation on the influence of FRP-to-concrete interface gap, caused by concrete shrinkage, on axial compressive behavior of concrete-filled FRP tube (CFFT) columns. A total of 12 aramid FRP (AFRP)-confined concrete specimens with circular cross-sections were manufactured. 3 of these specimens were instrumented to monitor long term shrinkage strain development and the remaining 9 were tested under monotonic axial compression. The influence of concrete shrinkage was examined by applying a gap of up to 0.06 mm thickness at the FRP-to-concrete interface, simulating 800 microstrain of shrinkage in the radial direction. Axial strain recordings were compared on specimens instrumented with two different measurement methods: full-and mid-height linear variable displacement transformers (LVDTs). Results of the experimental study indicate that the influence of interface gap on stress-strain behavior is significant, with an increase in interface gap resulting in a decrease and increase in the compressive strength and ultimate axial strain, respectively. It was also observed that an increase in interface gap leads to a slight loss in axial stress at the transition region of the stress-strain curve. Finally, it is found that an increase in the interface gap results in a significant decrease in the ratio of the ultimate axial strains obtained from mid-section and full-height LVDTs.
The Main Factors that Influence the Mechanical Properties of Honeycomb Board
Authors: Ma Cong Bo , Wang Yan Wei , Zou Guang Ping , Du Xuan
Published: August 2015

It’s very important to select appropriate dimensions for manufacture of honeycomb sandwich. In this paper, the experimental and theoretical methods were compared. The results are proved that the theoretical formula can be applied to engineering design. The impact factor of staties mechanical properties of honeycomb panels also was studied. And a theoretical basis for the design of honeycomb sandwich panels is provided.
Optimizing Detection Parameters of Magnetic Barkhausen Noise Using Heat Affected Zone in Welded Ship Steel Plate
Authors: Swallem M. , Blaow M.M. , Adarrat A.M.
Published: August 2015

Magnetic Barkhausen noise measurements on a welded marine steel plate were performed in a line that passes through the weld bead and extends to the base metal from both sides of the weld. The heat affected zone was characterized by a pattern in the peak height as a function of distance from the weld bead. Barkhausen noise profile analysis by extracting relevant parameters like peak position, profile area and profile half width was also performed. The result showed a clear variation in MBN profile parameters in a way similar to that of the profile peak height. It could be concluded that MBN profile parameters superimposed as a function of measurement distance from the weld bead may provide an accurate determination of the affected material near the weld bead. The variation in MBN profile parameters was enhanced by microstructural and mechanical changes along the measurement line. This experiment demonstrates that the Barkhausen noise profile parameters could be used to track various manufacturing and maintenance processes of steel instead of using a single parameter like the root mean square (rms) to eliminate the variability of results and narrow the tolerance of acceptance criterion.
Comparative Studies of Nanostructured Aluminum Alloys by Destructive and Nondestructive Testing
Authors: Lvova Natalia , Evdokimov Ivan , Perfilov Sergey
Published: August 2015

This work provides a comparative study of the mechanical properties of composite materials based on aluminum reinforced with carbon nanostructures. The study involved the tensile strength testing, as well as sclerometry and indentation in the submicron range. We determined the correlation of the values obtained for yield strength and hardness, and the tensile strength and morphology of the residual scratches.
Mobility Investigation of Nanoparticle-Stabilized Carbon Dioxide Foam for Enhanced Oil Recovery (EOR)
Authors: Mohd T.A.T. , Alias N. , Ghazali N.A. , Yahya E. , Sauki Arina , Azizi A. , Yusof Noorsuhana Mohd
Published: August 2015

Enhanced oil recovery (EOR) can extend the life of an oil field by providing additional drive mechanism to the crude oil. The use of carbon dioxide (CO2) in EOR application has shown a good potential, but it has some weaknesses such as viscous fingering. Viscous fingering problem can be solved by reducing the CO2 gas mobility, which can be achieved by transforming the CO2 gas into surfactant-stabilized foam. However, surfactant-stabilized foam is not very stable under harsh reservoir condition, which could be handled by introducing nanoparticle-stabilized CO2 foam. Thus, this paper aims to investigate the mobility of nanoparticle-stabilized CO2 foam at varying brine salinity (1 - 4 wt%), concentration of AOS surfactant (0.01 - 1 wt%) and concentration of nanoparticle (0.05 - 1 wt%). The volumetric phase ratio was fixed at 8 CO2/aqueous. The sand pack foam flooding test was conducted to measure the effectiveness of the formulated foam to displace the oil inside the porous medium through mobility and oil recovery measurement. It was found that foam mobility is inversely proportional to oil recovery. Mobility decreased when increase of brine salinity, surfactant and nanoparticle concentration, which has increased the oil recovery. Thus, it is important to reduce the foam mobility for efficient displacement process, which could minimize viscous fingering and enhance the oil recovery. This could be achieved by increasing the viscosity of displacing fluid (foam) for more stable displacement in EOR application.
The Electrochemical Study on Corrosion of Heat Affected Zone of Stainless Steel Weldment in Seawater under Different Welding Procedures
Authors: Gu Cai Xiang , Zhu Yun Peng , Li Shuang Ming , Ren Xiang Hua
Published: August 2015

The experiments were simulated based on the real environment of The East China sea. It were conducted to study HAZ seawater corrosion behaviors as well as effect of welding process on the corrosion performance of 304 stainless steel at different welding processes of argon arc welding with electrochemical technology. The results indicated that when the welding current increases, the corrosion rate of stainless steel sample will also increase while the open circuit potential will decrease. And with the increasing argon flow rate , the results will completely be opposite. The largest impedance size of the parent metal is 36.175 Ω/ cm2and the minimum impedance size of B1R is 12.531 Ω/ cm2.
Investigation on the Corrosion Behavior of Cast and Extrude AZ61 Mg Alloys in NaCl Atmosphere at High Temperature and Pressure
Authors: Tian Yun , Feng Li Jun , Wang Tian Zheng
Published: August 2015

We chose cast and extrude magnesium alloy AZ61 as materials and studied the influences of temperature, humidity, pressure and NaCl atmosphere on the corrosion products and corrosion mechanism by means of SEM, EDS and XRD. we could indicate the corr osion rate of extruded AZ61 magnesium is faster than that of cast AZ61 magnesium. Both th e rearrange of second ph ase and smaller grain size, which owing to the extrusion process, change the morphologies of corrosion products.
Modeling of Non-Isothermal Ferrite Transformation in Fe-C-Mn-Si Alloys
Authors: Dong Chao , Meng Dan , He Yan Lin , Fu Shi Yu , Li Lin
Published: August 2015

Based on Pham’s model, the non-isothermal ferrite transformation start temperature and time of Fe-C-Mn-Si alloys were deduced. The parameters of expression were predicted combined with experimental results. The relationship between ferrite transformation parameters Q , C and composition of Fe-C-Mn-Si alloys was obtained. Then the ferrite transformation start curve of Fe-C-Mn-Si alloys can be accurately predicted by the computational method, which can be extended to more complex multi-component alloy systems.
Study of Leaching Zinc from Difficult Dealt Zinc Oxide Ore with High Silicon in the Alkali
Authors: LI Yong Jia , Yang Da Jin
Published: August 2015

In this paper, the influencing factors in the process of alkali leaching of refractory zinc oxidize ores were studied. The influence of the particle size, reaction temperature, leaching time, alkali concentration and liquid-solid ratio on the leaching efficiency of zinc were investigated via leaching tests. The results indicate that the particle size has little influence on the leaching efficiency of zinc while the influences of other factors are larger. The optimal leaching condition is: the reaction temperature is 80 °C, the alkali concentration is 4.5 mol/L, and the leaching time is 1.5 h as well as the liquid- solid ratio is 10:1. In such conditions, the leaching efficiency can reach 82.22%.
The Influence of Different Gas Welding Flame on Corrosion Behavior of the Carbon Steel’s Heat Affected Zone in Seawater
Authors: Gu Cai Xiang , Liu Guang Wei , Xu Yu Dong
Published: August 2015

The influence of different flame of gas welding on corrosion behavior of the carbon steel’s heat affected zone in seawater were studied by the weight-loss method, electroanalytical chemistry method and surface and microstructure observation. The result indicate that when gas welding the carbon steel, the corrosion rate of the heat affected zone under the influence of mild carbonizing flame is 0.1252[g／(m2•h)], in contrast, the corrosion rate of that under the influence of neutral flame is 0.1025[g／(m2•h)]; the order of corrosion current shows as follows: Imild carbonizing flame>Ineutral flame>Ibase metal; the order of measured corrosion potential as follows: Ebase metal>Eneutral flame>Emild carbonizing flame. Compared with the base metal, the heat effected zone are more likely to corrosion, corrosion resistance of the sample under mild carbon flame are the worse.
Corrosion and Protection of Magnesium Alloys
Authors: Lv Yang Yang , Zhang Ling Feng
Published: August 2015

Magnesium alloy as a green material in the 21st century, because of its excellent physical and mechanical properties of metallic materials as an ideal in the automotive industry, electronic industry and aviation, aerospace and other industries[1]. However, poor corrosion resistance of magnesium alloys become an important issue hinder application of magnesium alloys[2]. So magnesium alloy corrosion problems and the current status of research paper reviews several magnesium alloy protection methods at home and abroad, and also highlighted with our latest laser shock (LSP) study of AZ91 magnesium alloy at high strain rates of corrosion resistance results.
The Fatigue Crack Propagation of Al–Mg–Mn–Zr Alloy with Erbium
Authors: Lei Xin , Huang Hui , Wang Huan
Published: August 2015

This study investigated the fatigue crack propagation of Al–Mg–Mn–Zr alloys with erbium. The research found that in this alloy the crack propagation path prefers to extend along the grain boundary. If there are too many second phases or impurities in the gain boundary, the crack propagation will be influenced. The dispersed Al3(Er, Zr) precipitate in the alloy can act as a core of heterogeneous nucleation to attract Mg, Zn and Al element, and reduce the large brittle Al3Mg2second phase appear on the grain boundary, so the fatigue crack propagation rate can be slow down. In addition, these Al3(Er, Zr) precipitate can pin the dislocation in the alloy to reduce stress concentration at the grain boundary, so it also has some positive effect to the fatigue crack propagation.
Study on the Thermal Field Distribution of Steel Claws for Anode in Aluminium Electrolysis Cell
Authors: Qin Qing Dong
Published: August 2015

The electricity consuming of aluminium electrolysis cell is affected by the voltage drop of anode steel claws during the aluminium electrolysis course. The resistivity of anode steel claws is affected by the temperature. In the present study, the thermal field distribution of anode steel claws was studied by finite element analysis. The results show that the thermal energy of anode steel claws come from anode carbon blocks and environment. The temperature of steel claws less than 1/3 height is affected by anode carbon blocks, and the other part is affected by surrounding temperature. According the results, the principle of the new anode steel claw design is proposed.
Compatibility between the Molten Mg-25Al-15Zn-14Cu Alloy and Stainless Steel for Phase-Transformation Thermal Storage Facility
Authors: Ai Xiao Ling , Fan Xiao Ming , Lei Chang , Cheng Xiao Min
Published: August 2015

The compatibility of molten Mg-25Al-15Zn-14Cu alloy with several candidate vessel shell materials such as 304 stainless steel, 201 stainless steel for phase-transformation thermal storage facility were evaluated by means of immersion corrosion test at 500°C for 1000 h. The microstructure, element distribution and surface corrosion layer structure and phase composition of the cross section of corrosion samples were analyzed by using optical microscope (OM), X-ray diffraction (XRD) and electron microprobe analysis (EPMA). The results show that two kinds of stainless steel have good compatibility in the molten Mg-25Al-15Zn-14Cu alloy. The thickness of the erosion layer is less than 0.1mm. The corrosion interface of corrosive material in the molten Mg-25Al-15Zn-14Cu alloy can be divided into the base layer, the diffusion layer, the corrosion layer, segregation layer (C, Cr, Ni), linked coating layer.
Synthesis and Salt Resistance of Novel Polyampholyte P(DMAPMA-co-HEA)-CA
Authors: Li Xiang , Cai Meng Jun , Chen Jian Ding , Taha Mohamed
Published: August 2015

A novel polyampholyte P(DMAPMA-co-HEA)-CA was prepared by the quaternization of chloroacetic acid (CA) to P(DMAPMA-co-HEA), which was synthesized by the copolymerization of 2-hydroxyethyl acrylate (HEA) and N-(3-dimethylaminopropyl)maleamic acid (DMAPMA). The isoelectric point (IEP) of P(DMAPMA-co-HEA)-CA was studied by titration, and the salt resistance of P(DMAPMA-co-HEA)-CA expressed by viscosity was determined in sodium chloride solution by Ubbelohde viscometer. The results show that P(DMAPMA-co-HEA)-CA possesses excellent salt resistance in sodium chloride solution.
Dynamic Compressive Behavior and Damage Mechanism of Magnesium Alloy
Authors: He Huan Ju , Zhang Ling Feng , Li Shao Zhe
Published: August 2015

The dynamic compression test was carried out for the AZ91 Magnesium alloy of as-cast and aging state with a split Hopkinson pressure bar, and the dynamic behavior has been investigated. Finally the fracture surface of samples at the different strain rates was analyzed by scanning electron microscope (SEM). The results show that compared with the as-cast AZ91, it is more impressible for the solid solution and age-treatment AZ91 at the similar strong strain rates, while the stress-strain curve has the duality of positive and negative effects as the variation of strain rate.
Prediction of Chip Morphology and Formation in High Speed Milling of Hardened Steels
Authors: Pang Jun Zhong , Huang Xiao Bin , Chang Dou Dou , Pan Jie
Published: August 2015

A P20 steel are machined in the milling speed range of 200 to 942m/min. The morphology and formation of the chips are investigated at various speeds. The serrated chips with adiabatic shear band are observed at a high milling speed. The transition from continuous to serrated chip formation is favored by the increase in work material hardness and milling speed. The study assumes that the chip segmentation is only induced by adiabatic shear banding, without material failure in the primary shear zone. Based on adiabatic shear theory, using the JC and the power material constitutive equation, the modified material model which takes into a strain softening is developed for prediction of the serrated chip formation. Experimental measurements are compared with the simulation results.
Strength of Bonded Joints of Polypropylene after Radiation Cross-Linking
Authors: Bednarik Martin , Manas David , Manas Miroslav , Stanek Michal , Navratil Jan , Mizera Ales
Published: August 2015

In this study there was found that ionizing beta radiation increased the strength of bonded joints and improved the adhesion properties of polypropylene (PP). Generally, for the formation of quality bonded joint it is important to wet the adhesive bonding surface well. Wettability is characterized by the contact angle of wetting. The liquid has to have a lower surface tension than the solid in order to be able to wet the solid substance. The measurement results indicated that ionizing beta radiation was a very effective tool for the improvement of adhesive properties and increased the strength of bonded joints of polypropylene. Bonded surfaces with ionizing beta radiation doses of 0, 33, 66 and 99 kGy were irradiated. The best results were achieved by irradiation at dose of 66 kGy by which the highest surface energy and the highest strength of bonded joints of PP were achieved. The strength of bonded joints after irradiation was increased up to 450 % compared to untreated material. A similar trend was observed even for surface energy.
Study of Charpy Impact Properties of PC with Different Amount of Recycled Material and Temperatures
Authors: Senkerik Vojtech , Stanek Michal , Manas David , Manas Miroslav , Skrobak Adam , Ovsik Martin
Published: August 2015

This research paper deals with assess effect amount of recycled material on Charpy impact behavior. Valuation of recycled material effect takes place on four kinds of thermoplastic materials, high-heat polycarbonate is always mixture with different amount of recycled material (pure polycarbonate, polycarbonate with 20 percent of recycled material, polycarbonate with 30 percent of recycled material and pure recycled polycarbonate). Specimens were prepared by the mostly used technology for production products, which is injection molding. Each kind of material is one by one loaded by different temperatures; at reduced, and three increased temperatures and consequently tested. To determine influence of recycled material was used Charpy impact test.
Irradiation of Polyamide Measured by Micro-Indentation Test
Authors: Ovsik Martin , Manas David , Manas Miroslav , Stanek Michal , Skrobak Adam , Senkerik Vojtech
Published: August 2015

Cross-linking is a process in which polymer chains are associated through chemical bonds. This research paper deals with the possible utilization of irradiated polyamide. Influence of the intensity of irradiation on micro-indentation hardness was investigated. Material properties created by β – radiation are measured by micro-indentation test using the DSI method (Depth Sensing Indentation). Hardness increased with increasing dose of irradiation at everything samples; however results of micro-indentation test shows increasing in micro-mechanical properties of surface layer. The highest values of micro-mechanical properties were reached radiation dose of 99 kGy, when the micro-mechanical values increased by about 18%.
Mechanical Behavior of the Cr3C2 Compound at High Pressure and High Temperature
Authors: Jiang Bin Li , Kou Zi Li , Ma De Jiang , Wang Yong Kun , Li Chun Xia , Duan Wen Rui , Yang Xing Hui
Published: August 2015

In the present study, we present a novel method to sinter Cr3C2 powders under high pressure without any addittives. The sintering Cr3C2 samples were charaterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), relative density measurements, Vicker’s hardness tests and Fracture toughness tests. The reasults show that Cr3C2 powders could be sintered to be bulk under the conditions of 3-5 GPa, 800-1200 °C and the heat preservation for 15 min. Moreover, the sintering body of Cr3C2 compound with the relative density of 99.84% by simultaneously tuning the pressure-temperature conditions exhibited excellent mechanical properties: a Vickers hardness of 20.3 GPa and a fracture toughness of ~8.9 MPam1/2. These properties were much higher than that by using the previous methods. The temperature condition obtained good mechanical properties in the experiment was about 1/3 lower than that using any other methods owing to the high pressure.
Influence of Technological Parameters on Material Flow
Authors: Stanek Michal , Manas David , Manas Miroslav , Senkerik Vojtech , Skrobak Adam , Navratil Jan
Published: August 2015

Injection molding is one of the most extended polymer processing technologies. It enables the manufacture of final products, which do not require any further operations. The tools used for their production – the injection molds – are very complicated assemblies that are made using several technologies and materials. Delivery of polymer melts into the mold cavity is the most important stage of the injection molding process. The fluidity of polymers is affected by many parameters Inc. mold design. Evaluation of set of data obtained by experiments in which the testing conditions were widely changed shows that the quality of cavity surface and technological parameters (injection rate, injection pressure and gate size) has substantial influence on the length of flow.
Micromechanical Properties of Thermoplastic Elastomer (TPE-E)
Authors: Manas David , Ovsik Martin , Manas Miroslav , Stanek Michal , Stoklasek Pavel , Bednarik Martin , Mizera Ales
Published: August 2015

The process of radiation crosslinking helps to improve some mechanical properties of polymer materials. Micromechanical changes in the surface layer of Thermoplastic elastomer (TPE-E) modified by beta radiation were measured by instrumented test of microhardness. The specimens were prepared by injection technology and subjected to radiation doses of 0, 66, 99, 132 kGy. Measurements of microhardness showed considerable changes of behavior of surface layer in middle as well as high radiation doses with higher values of indentation hardness and stiffness.
Study on the Annealing Process of a Cu-Zn-Al-Ni Alloy
Authors: Fu Xing , Wang Wen Xu , Li Yao , Zuo Yu Bo , Wang Ping , Cui Jian Zhong
Published: August 2015

Aluminum brass possesses an attractive combination of properties including high strength, high thermal and electrical conductivity, good mechanical workability, excellent corrosion resistance, low susceptibility to stress corrosion cracking. This make it a preferred choice for bimetal strips. The materials for preparing bimetal strips with cold roll bonding should have a good plasticity. In the present work, a Cu-Zn-Al-Ni alloy was proposed and the annealing process for this aluminium brass alloy was studied. The effect of annealing temperature and annealing time on the microstructure and mechanical properties was investigated. The proper annealing parameters were obtained.
Analysis on the Optimal Process of Aluminum Profile Extrusion with Two-Hole Dies
Authors: Miao Cong , Yang Hai Bo
Published: August 2015

In this paper, using orthogonal design method, considering the extrusion temperature, extrusion speed, extrusion billet, die structure, which will affect the uniformity of the metal flow[1]. Using the outlet velocity average standard deviation, the average pressure and the mean maximum equivalent stress as the criterion, select the optimal process scheme of two-hole dies aluminum profile extrusion. And the optimal scheme is validated by simulation and, the results show that the extrusion velocity is uniform, no forming defects, it can stably forming. At the same time, the experiment provides theoretical guidance for real extrusion production with multi-hole dies.
Experimental Investigations on Cylindrical Grinding Temperature of Silicon Carbide
Authors: Wu Chong Jun , Li Bei Zhi , Liang Steven Y. , Yang Jian Guo
Published: August 2015

The grinding process requires a high energy expenditure per unit volume of material removed. The high temperature generated in abrasive processes is the main factor responsible for thermal damage to a ground surface. An investigation was undertaken to explore the temperature characteristics in high speed grinding (HSG) of silicon carbide (SiC) with a vitrified diamond wheel. A grindable thermocouople technique including a NI-DAQ device will be used to measure the grinding temperature. This paper will discuss the temperature characteristics in high speed grinding of SiC in detail and give an experiment-based temperature distribution model for SiC. A molecular dynamics simulation will be used to illustrate the effect of a high loading rate on SiC material’s mechanical property, which will further elaborate its unique HSG temperature characteristics. The experimental investigation will provide more practical application support in utilizing HSG technology in a high quality ceramic grinding.
Studying of Microstructure and Properties of Selective Laser Melted Titanium-Based Alloy
Authors: Popovich Anatoly A. , Sufiiarov Vadim Sh. , Polozov Igor A. , Borisov Evgenii V. , Maximov Maxim Y.
Published: August 2015

The article presents the results of selective laser melting of Ti-6Al-4V alloy. It was studied phase composition and microstructure of the initial powder material, the specimens manufactured by Selective Laser Melting and also the specimens after heat treatment. The effect of heat treatment on microstructure and mechanical properties of the specimens was shown. It was studied the mechanical behavior of the manufactured specimens before and after heat treatment at room and elevated temperatures as well. After heat treatment tests showed that the specimens have decent mechanical properties both at room and elevated temperatures.
Study of Circulation of Reaction Liquid in Liquid Phase Synthesis of LiFePO4 as Cathode Material
Authors: Ma Jun Jun , Zhou Jia , Zu Xue Min , Wang Xing Yao
Published: August 2015

LiFePO4 as cathode materials for lithium-ion battery were prepared by a liquid-phase method which utilizes FeSO4•7H2O, NH4H2PO4, H2O2, CH3COOLi and glucose as raw materials. The aqueous can be directly used in the synthesis of FePO4•xH2O without any treatment and the ethanol should be distilled before the synthesis of LiFePO4. The result showed that the high purity of FePO4•xH2O can be achieved even prepared with the aqueous which was used for five times. LiFePO4 cathode material prepared with the distilled ethanol exhibited the best initial discharge capacity of 156.3 mAh•g-1 and the capacity retention ratio 99.49% after 30 cycles at 0.1 C rate.
Microstructure and Properties of TA1 TIG Joint via Micro-Arc Oxidation
Authors: Guo Yu Peng , Di Shi Chun , Lv Hong Wei
Published: August 2015

This paper applied the micro-arc oxidation technology to TIG weld joint based on titanium alloy. The optical microscope, SEM, XRD and polarization curve were used to analyze the joints metallographic phase, the coating morphology, the phase composition and corrosion resistance. Research results showed that the grain was grew gradually coarser from base metal to joint. The joint surface obtained a uniform morphology after micro-arc oxidation. The joint and base metal was made up of α-Ti and their coatings are mainly composed by rutile-TiO2. The surface morphology and phase composition are similar after micro-arc oxidation. Polarization curve tests demonstrated that the corrosion potential performance of the coating was enhanced by micro-arc oxidation.
Influence of Machining Parameters of the Drilling Polymers UHMW-PE and PTFE
Authors: Ferreira Lizardo Breno , Machado Gomes Vieira Luciano , Campos Rubio Juan Carlos , Araújo Câmara Marcelo
Published: August 2015

Over the years, with the increasing development of engineering materials, the emergence of new composites, fiber metal laminated, biomaterials, metal alloys etc., and with demand for products less expensive, less polluting and more efficient, the manufacturing engineering also needs to develop to be able to process these new materials. Materials and tool geometries, intelligent mechanisms, modular machines, also follow this setting. To that end, this work comes to raise the main parameters that influence in the hole quality surface of finished product. Were used two polymeric materials, ultra high molecular weight polyethylene (UHMW-PE) and polytetrafluoroethylene (PTFE), two feed rates, three rotations and three tool geometries, allowing to identify which of these parameters have greater influence on the thrust force and the characteristics of the finished product and dimensional deviation.
An Experiment Study on Squeeze Test and Flow Behavior Analysis of Concentrated Carbon Black Suspension
Authors: Omarbekova Alnura , Ramachandran Ramakrishnan , Yertayev D. , Smagulov Dauletkhan
Published: August 2015

Carbon black suspension is investigated using a squeezing test, which compresses a disk of paste between two parallel plates, one of which is moving at a constant speed. From this test, the two-phase nature of carbon black suspension can be evidenced. Liquid migration is observed at low compression speed. This test is also a good tool for constructing a two-phase model for paste flow modeling. The concentrated suspension is composed of a powder of activated carbon black and a Newtonian liquid phase.
Experimental Analysis of a Vapor Chamber Applied to Thermal Management of Microelectronics
Authors: de Souza Obata Daniel Henrique , Alves Thiago Antonini , Bazani Márcio Antonio , Paschoalini Amarildo Tabone
Published: August 2015

In this research, a vapor chamber embedded in the base of a heat sink was experimentally analyzed for the application in thermal management of microelectronics. The vapor chamber was produced by a copper and molybdenum alloy with length of 240 mm, width of 54 mm, thickness of 3 mm, and capillary structures composed by copper screen meshes. The working fluid used was de-ionized water. The pure aluminum heat sink was cooled by air forced convection and the evaporator vapor chamber was heated using an electrical resistor simulating integrated circuit power dissipation. The experimental tests were done in a suction type wind tunnel with open return for a heat load varying from 20 to 80 W and for an airflow velocity varying from 1 to 4 m/s. The experimental results showed that the considered vapor chamber worked successfully, maintaining low operating temperature.
Experimental Verification of a Stochastic Fatigue Crack Growth Model
Authors: Ni C.C.
Published: August 2015

The study is focused on the experimental verification of a proposed polynomial stochastic fatigue crack growth model. The model was assumed that the fatigue crack growth rate equals to a deterministic polynomial function multiplied by a stationary lognormal random factor. Compact-tension specimens cut from a 2024-T351 aluminum-alloy plate were used for fatigue crack growth experiments under constant-amplitude loads performed on thirty specimens. The comparison of median crack growth curves was made between analytical and experimental outcomes. For extreme case of lognormal random variable, the comparisons of the fatigue crack growth curve, percentile fatigue crack growth curve, probability of crack exceedance, and distribution function of random time between analytical and experimental results were also investigated.
A Computer-Aided-Design (CAD) System for Four-Step Three-Dimensional Braiding
Authors: Wang Qi , Wang Jian Ming
Published: August 2015

To estimate the precise mechanical properties of the three-dimensional (3D) braided composite, a geometric study is needed. Owing to the complexity of the yarn paths inside the preform, the geometric modeling for 3D braided composite is always time consuming. In this paper, an efficient method, namely preform boundary reflection (PBR) method, is proposed for motion model construction in geometric study. Furthermore, the CAD simulation system was developed for integral geometric descriptions of 3D braided preform with different parameters. Compared with the traditional method, the novel method significantly simplifies the simulation process without affecting the precision of geometric structure. As a result, the structure design for composite preform is effectively accelerated. The new method establishes the foundation of microstructure and mechanical properties analysis for the preforms with complex geometric structures.