bluuebunny/crossref_metadata_2025 huggingface dataset:
Ti-Mg Alloy Powder Synthesis via Mechanochemical Reduction of TiO2 by Elemental Magnesium
Authors: Mushove Tafadzwa , Chikwanda Hilda Kundai , Machio Christopher , Ndlovu Sehliselo
Published: August 2009

This paper reports the preliminary results of an investigation on the synthesis of a Ti-Mg alloy powder through mechanochemical processing of TiO2 and Mg powders. TiO2 was mixed with elemental Mg according to a nominal stoichiometric composition with 15% excess Mg. The powder mixture was mechanically milled in a Simoloyer high energy ball mill for 5 different durations. Contamination was minimised by processing under a high purity argon atmosphere.
Changes in phase composition were studied by XRD techniques. TiO2 was reduced, as shown by the formation of MgO. The extent of the reduction, as indicated by XRD peaks’ intensities, increased with milling time. XRD spectra of powders milled for 24 hours revealed virtual disappearance of TiO2 peaks and there was no evidence of elemental Ti. The lattice parameter of the resulting Ti metal was larger than that of elemental Ti. This implies that the Ti was alloyed with free Mg to produce Ti-Mg alloy powder. The lattice parameter increased with increasing milling time.
Effect of Grain Size on the Performance of Extruded Magnesium Alloy Tubes in Three-Point Bending
Authors: Hilditch Tim B. , Atwell Dale , Beer Aiden G.
Published: August 2009

The performance of extruded AZ31, AZ61 and AM-EX1 tubes was examined in three-point bending. Different extrusion temperatures were used to investigate the effect of grain size on the load-carrying capacity, energy absorption and fracture propensity of the tubes. Results showed that while the peak load increased with a smaller average recrystallised grain size, the retention of large elongated un-recrystallised grains in the microstructure reduced the load. The presence of the large elongated grains also appeared detrimental to the ability of the tube to deform before fracture.
Tensile and Compressive Properties for Crashworthiness Assessment of a Large AZ31 Extrusion
Authors: Xu Su , Tyson W. R. , Bouchard R. , Eagleson Roy
Published: August 2009

Tensile and compressive tests of a large AZ31 extrusion were performed along extrusion and long transverse directions over a range of strain rate (0.00075 s-1 to 9 s-1) and temperature (100°C to -143°C). The effects of strain rate, temperature, sample orientation and load direction (tension or compression) on mechanical properties are reported and discussed. The yield strength of tensile samples along the extrusion direction can be described by a constitutive equation using the conventional rate parameter for thermally activated deformation.
Quantitative Determination on Hot Tearing in Mg-Al Binary Alloys
Authors: Zhen Zisheng , Hort Norbert , Huang Yuan Ding , Petri Nicolai , Utke Oliver , Kainer Karl Ulrich
Published: August 2009

Hot tearing, or hot cracking, is one of the most severe solidification defects commonly encountered during casting. It is such a complicated phenomenon that a full understanding is still not yet achieved, though it has been extensively investigated for decades. Most contributions are still based on qualitative characterisations. The purpose of this work is to develop a method that can quantitatively evaluate and investigate hot tearing behaviour. The principle is based on contraction stress/force measurements. The measured contraction force has been proven to be able to evaluate the hot tearing susceptibility as a more straightforward and quantitative index. By analyzing the contraction force curve, information can be obtained for both the initiation and the propagation of the hot tear. With this method, the influence of mould temperature and Al content on hot tearing behaviour of Mg-Al binary alloys has been investigated. The contraction force curves also indicate that the liquid refilling plays an important role during the hot crack propagation. With a lower cooling rate and higher onset temperature of hot tear, the remaining liquid is more favourable to refill the initiated hot crack, and consequently interrupts the propagation of cracks or possibly completely heals the cracks.
Novel Grain Boundary Solute Architecture in a Nanostructured Ultra-High Strength 7075 Aluminium Alloy
Authors: Liddicoat Peter V. , Liao Xiao Zhou , Ringer Simon P.
Published: August 2009

In recent years, the pursuit of higher strength metals and alloys has led researchers to nanometer scale grain refinement. New nanocrystalline engineering techniques have successfully increased properties for a wide range of materials. Here we report a nanocrystalline 7075 alloy processed by high-pressure torsion that exhibits ultra-high strength and features a hierarchical solute architecture. The new hierarchy of solute architecture was discovered through high-resolution characterisation using novel techniques we have developed in atom probe tomography. These new techniques – nanotexture and fine scale solute cluster measurements, are the focus of this paper. Our results indicate that nanometer-scale engineering of solid solutions could offer a pathway towards a new generation of super-strong alloys that hold promise for creating entirely new regimes of property-performance space.
Research and Development of Non-Ferrous Melting Energy
Authors: Prasertsook Somsak
Published: August 2009

The objective of this research is to develop an existing crucible furnace fueled by diesel fuel into an energy saving LPG fueled furnace. The Non- ferrous melting furnace will be used to melt Aluminium and Copper alloys.
The results of the research are as follows:
1. The furnace and equipment improvements outlined in this research will save an average fuel cost of 26.90 percent when using diesel oil.
2. When comparing the use of LPG fuel with diesel oil to melt aluminium alloy, LPG use results in an average cost saving of 43.18 percent as compared to diesel, while copper alloy melting results in an average cost saving of 50.83 percent.
The world energy crisis has impacted economic growth in the developing countries mainly due to the high costs of importing energy such as crude oil from middle eastern countries where the high price of the oil has lead to a higher cost of products.
Thus manufacturers must consider this when embarking of significant capital expenditure.
It is believed that alternative energy is the way to relieve the energy crisis situation. Using suitable energy is one way to save on production costs. Foundries which produce non - ferrous metals such as aluminium and copper Alloy still use oil crucible furnaces as the source of heat energy. If they change the energy source from oil to be liquefied petroleum gases (LPG) the melting cost will be decreased.
This research was the experimentally conducted by melting non - ferrous metals within a crucible furnace using either LPG or diesel oil and then comparing the consumption levels. Before the experiment we modified an existing crucible furnace which used diesel oil to be the experiment furnace. However for reference data this researcher took the Capacity table of crucible furnaces from Pyro - Industrial Systems Company U.S.A.
Mechanical Properties of an Accumulative Roll Bonded Aluminium Alloy Composite
Authors: Al-Buhamad O. , Quadir M. Zakaria , Ferry Michael
Published: August 2009

A multilayered sheet composite of commercial purity Al and Al-0.3%Sc alloys was produced by accumulative roll bonding. The final sheet material consisted of 64 ultra fine grained layers, each of ~7.8mm in thickness. The as-deformed material was annealed at temperatures ranging from 250 to 350°C to study the changes in microstructure and their associated influence on mechanical properties. The as-deformed structures largely comprised of high angle grain boundaries in the Al layers and low angle grain boundaries in the Al(Sc) layers. During annealing, the structures in the Al(Sc) layers remained unaltered, whereas the Al layers recrystallized rapidly to the full layer thickness. The mechanical properties of the Al-Al(Sc) composite were measured and found to be unique in strength and ductility with annealing temperature having a significant influence on these properties.
Work- and Age-Hardening Behaviour of a Commercial AA7108 Aluminium Alloy
Authors: Westermann Ida , Hopperstad Odd Sture , Marthinsen Knut , Holmedal Bjørn
Published: August 2009

Understanding and prediction of the mechanical properties of aluminium alloys are of great importance with respect to e.g. strength requirements and forming operations. In the 7xxx alloying system several mechanisms influence the hardening behaviour of the alloys, e.g. particle size and distribution, dislocation density, and alloying elements in solid solution. This work is an experimental study of work- and age-hardening considering a commercial AA7108 alloy in the as-cast and homogenized condition. Tensile specimens have been exposed to a solution heat treatment and a two-step age-hardening treatment with varying time at the final temperature. The tensile data for the different tempers have been evaluated in elucidation of already existing models based on the one-parameter framework by Kocks, Mecking, and Estrin. The particle size has been further investigated in the transmission electron microscope for one under- and one over-aged condition and the influence of particles on work-hardening behavior has been discussed.
TiAl Turbochargers for Automobile Application
Authors: Zhang Ji , Xia Kenong
Published: August 2009

A textured microstructure was produced in the TiAl turbocharger blades and platelike TiAl samples in the process of conventional casting, in which the lamellar orientation is parallel to the plate surfaces. A microstructure design specific to the turbocharger blades was therefore proposed based on the preponderance in tensile properties, creep rupture life and creep resistance along the preferential lamellar orientation. The mechanical capacity of the TiAl turbochargers has been validated through endurance tests.
Fatigue Crack Propagation Mechanisms of Long and Small Cracks in Al-Si-Mg and Al-Mg Cast Alloys
Authors: Lados Diana A.
Published: August 2009

Fatigue crack growth of long and small cracks was investigated for various Al-Si-Mg and Al-Mg cast alloys. Low residual stress was ensured during processing to concentrate on microstructural effects on crack growth. Compact tension and single edge tension specimens were fatigue crack growth tested at room temperature and stress ratio, R = 0.1. Microstructure related mechanisms were used to explain the near-threshold behaviour and crack growth response in Regions II and III for each material considering relevant microstructural features such as SDAS, grain size, and volume fraction and morphology of eutectic Si. Threshold behaviour of long cracks is attributed to closure-dependent mechanisms. In Regions II and III, the changes in crack growth mechanisms were explained through correlations between the extent of the plastic zone ahead of the crack tip and material-specific microstructural damage. Threshold behaviour of small cracks is explained through closure-independent mechanisms, specifically through the barrier effects of controlling microstructural characteristics specific to each material. Recommendations for integrating materials knowledge in structural design for fatigue performance are given.
Quantitative Investigation of Hot Tearing of Al-Cu Alloy (206) Cast in a Constrained Bar Permanent Mold
Authors: Li Shi Min , Apelian Diran , Sadayappan K.
Published: August 2009

The mechanisms of hot tearing are generally understood; inadequate feeding initiates the tear and further thermal deformation propagates the tear. However, a reliable experimental methodology/apparatus to quantitatively measure and characterize hot tearing is not available for the casting industry. In this study, a hot tearing apparatus with a load cell and LVDT developed at CANMET-MTL was used to measure the load and contraction in the mushy zone of an Al-Cu alloy. The onset of hot tearing can be determined from the load curve, its first derivative and cooling curve. The linear solidification contraction of the bar is measured. Alloy 206, which is an alloy that is quite prone to hot tearing was evaluated by the apparatus; results are given and discussed.
Replication of Microscale Features via Investment Casting Using the Example of an Aluminium Intake Manifold of a Gasoline Engine with an Inner Technical Shark Skin Surface
Authors: Ivanov Todor , Bührig-Polaczek Andreas , Vroomen Uwe
Published: August 2009

Within the project “Functional Surfaces via Micro- and Nanoscaled Structures” an investment casting process to produce 3-dimensional functional surfaces down to a structural size of 1µm on near-net-shape-casting parts will be developed. The common way to realise functional microscale features on metallic surfaces is to use laser ablation, electro discharge machining or micro milling. The handicap of these processes is their limited productivity. In order to raise the efficiency, microscale features will be replicated by use of the investment casting process. The main research objective deals with the investigation of the single process steps with regard to the moulding accuracy. Actual results concerning making of the wax pattern and the ceramic mould as well as the casting of an Aluminium alloy will be presented. By using the example of an intake manifold of a gasoline race car engine a technical shark skin surface was defined in order to reduce the drag of the in-coming air. Possible process stategies to realise microscale features on an inner surface of a casting part were developed.
Counter-Gravity Casting Equipment and Technologies for Thin-Walled Al-Alloy Parts in Resin Sand Molds
Authors: Jie Wan Qi , Li Xin Lei , Hao Qi Tang
Published: August 2009

A counter-gravity casting equipment (CGCE) has been developed, which is specially designed for the production of large-size thin-walled high-quality aluminum alloy parts with resin sand molds. In this equipment, molten metal will be pushed upward counter-gravity into the mold at predetermined rate by compressed air, and solidified at an increased pressure. The equipment uses assembled valve system developed ourselves, and has sensitive pressure-adjusting property. All of the casting parameters, including filling rate, pressure-exerting sequence, pressure hold time etc., can be closely controlled by a self-designed computer program. Up to 2 ton casting can be produced with the equipment. Compared to the castings produced under conventional gravity conditions, the castings under counter-gravity condition have generally high soundness, higher tensile strengths and ductility. The pinhole defects are also degraded obviously. The equipment and the technology have been widely adopted by several users in China for the production of large-size thin-walled aluminum alloy castings with high property requirements.
Optimization of Aluminium Die Casting Alloys for Enhanced Properties
Authors: Wang L. , Apelian Diran , Makhlouf M.M.
Published: August 2009

Selecting an aluminum die casting alloy for a particular application often poses a challenge to designers and engineers. It is often difficult and sometimes not possible to find an alloy that meets all the requirements of the application; and in other times the alloy can be found, but it has a wide specified compositional range, and thus it exhibits a large variation in properties. Therefore, there is always a need to optimize existing alloys or to develop new alloys so that they meet the requirements of a given application. In order to help with the alloy selection and alloy development processes, we developed an electronic database for aluminum die casting alloys – i-Select-Al. This software can help its user to quickly select an alloy for a specific application from a comprehensive list of commercial alloys. Alternatively, it can help its user with the design of a new alloy to meet the requirements of the application. This paper presents a study in optimizing A380 alloy with the help of i-Select-Al. A380 alloy is the most commonly used die casting alloy, but it has a wide compositional range and therefore a wide range of properties. In this study, we optimized the mechanical properties of A380 alloy by optimizing its chemical composition. The Quality Index was used to quantify the changes in the alloys’ properties in response to changes in chemical composition. Two alloys were designed: one has a composition within the A380 alloy specification, and the other has a composition slightly outside the A380 alloy specification. Both alloys showed significant improvements in room temperature tensile properties and a substantial increase in the Quality Index over a commercially available A380 alloy.
The Influence of Intensification Pressure on the Gate Microstructure of AlSi3MgMn High Pressure Die Castings
Authors: Otarawanna Somboon , Gourlay Christopher M. , Laukli Hans Ivar , Dahle Arne K.
Published: August 2009

This article focuses on the influence of intensification pressure (I.P.) on the feeding through the gate during high pressure die casting (HPDC). Two values of intensification pressure, the lowest and highest possible for the HPDC machine used, were applied to cast AlSi3MgMn tensile-bar specimens. The castings produced with higher I.P. contained a lower total fraction of porosity, as expected. Microstructural characterisation of the gate region showed markedly different features in and adjacent to the gate at the two levels of I.P. used. The microstructures indicate a change in feeding mechanism with increasing I.P. At high I.P. shear band-like features exist through the gate, suggesting that strain localisation in the gate is involved in the feeding of solidification shrinkage during the I.P. stage. At low I.P. such shear bands were not observed in the gates and feeding was less effective, resulting in a higher level of porosity in the HPDC parts.
Metallurgical and Foundry Parameters for the SSM Forming of High Strength Aluminium-Zinc-Magnesium-Copper (7075) Alloy
Authors: Juganan L.G. , Govender Gonasagren , Mulaba Bafubiandi A.F.
Published: August 2009

Aluminium-Zinc-Magnesium-Copper, 7075, alloy offers both high strength (comparable with those of alloy steels) and very good ductility which makes this alloy group suitable for many automotive, aerospace and defence applications, however the alloys are difficult to cast because of their tendency for Hot Tearing. The Semi-Solid Metalforming (SSM) casting technique allows for near net shape casting using High-Pressure Diecasting (HPDC). The lower forming temperature reduces the problem of Hot Tearing. The CSIR has developed a rheocasting process which prepares semi-solid slurries from molten metal which can then be formed using HPDC. Since 7075 is a wrought alloy there is limited information on the foundry practice for this alloy. The aim of this study is to determine the foundry practice for 7075 aluminium alloy. Melting trials and optical emission spectroscopy on, AA7075 was conducted to study the effect of metallurgical melting parameters and compositional variations. 7075 Alloy was melted using a resistance melting furnace and compositional variation in the crucible for varying holding times was evaluated to determine the degree of segregation of key alloying elements. Results have shown some compositional variations.
The In Situ Fabrication of Al-AlN Composites from Metal Powders and their Resistance to Wear and Cavitation
Authors: Qian Ma , Kondoh Katsuyoshi , Kent Damon , Umeda Junko , Yu Peng , Schaffer Graham B.
Published: August 2009

Recent breakthroughs in the sintering of aluminium alloys under nitrogen have opened the way for the in-situ fabrication of Al-AlN composites in a controllable and reproducible fashion over a wide range of volume fractions of AlN. This work reviews the fundamentals for the in-situ fabrication of the Al-AlN composites from metal powders and highlights their technical potential for niche applications because of their excellent resistance to cavitation erosion in water and their unusually low friction coefficient under oil lubrication.
Pressure Assisted Sintering of an Aluminium Alloy
Authors: Bonner Stephen J. , Schaffer Graham B. , Yao Ji Yong
Published: August 2009

An aluminium alloy was sintered using a conventional press and sinter process, at various gas pressures, to observe the effect of sintering gas pressure on the densification rate. Compacts of aluminium alloy 2712 (Al-3.8Cu-1Mg-0.7Si-0.1Sn) were prepared from elemental powders and sintered in a horizontal tube furnace under nitrogen or argon at 590°C for up to 60 minutes, and air cooled. The gas flow was adjusted to achieve specific gas pressures in the furnace. It has been found that increasing the nitrogen pressure at the start of the isothermal holding stage to 160kPa increased the densification rate compared to standard atmospheric pressure sintering. Increasing the nitrogen pressure further, up to 600kPa, had no additional benefit. The densification rate was increased significantly by increasing the gas pressure to 600kPa during both heating and isothermal holding. Under argon the elevated pressure did not increase the densification rate. Results seem to suggest that the beneficial effect of the elevated pressure on the rate of densification is related to nitride formation.
Rapid Prototyping of Aluminium Alloy Parts: The Effect of Infiltration Atmosphere
Authors: Yu Peng , Qian Ma , Schaffer Graham B.
Published: August 2009

An investigation has been made on the infiltration behaviour in rapid prototyping of Al alloy parts under different infiltration atmospheres. An Al 6061 alloy preform was first prepared by selective laser sintering. Then the aluminium precursor powders in the preform were converted into AlN to form a skeletal AlN structure, which was subsequently pressureless infiltrated with a molten Al 6061 alloy under nitrogen, argon or vacuum. The pathway of the infiltrant was determined by density measurements in conjunction with metallographic examination and quantitative image analysis. Detailed comparison of the microstructures at the surface and the centre of the as-infiltrated samples indicates that the pathway into the porous preform is dependent on the infiltration atmosphere. Under vacuum, the infiltrant fills the interior of the preform first and then propagates to the surface. In contrast, under nitrogen or argon, the infiltrant penetrates along the surface prior to filling the interior.
Aluminium Cutting Heat Distribution - Thermal Transfer Function Approach
Authors: Vyroubal Jiri , Maly Jan
Published: August 2009

The development of a thermal model for materials during cutting currently represents a complex research topic. This paper presents an approach to calculating the heat distribution in an aluminium alloy during the cutting process. The alloy used, AlCu4PbMgMn, is monitored during machining without a cooling liquid. Special Thermal Transfer Functions (TTF) are used to calculate the quantity of heat transferred from the cutting tool into the aluminium workpiece.
Sustainable Development for the 21st Century: Challenges and Opportunities for Light Metals
Authors: Apelian Diran , Jorstad John L.
Published: August 2009

By 2050 the world population will reach over nine billion and “flattening of the world” will be an understatement. We anticipate burgeoning needs regarding energy resources, transportation, housing, food distribution/packaging for the masses, recycling, and health care/ health care delivery, not to mention climate change and environmental issues. World population is increasing at an average rate of 1.4%, and in contrast world energy consumption is increasing at an average rate of 1.7%. Such an imbalance is not sustainable. From a societal perspective, engineers have played a major role to enhance the quality of life in our world. Sustainable development in the 21st Century is perhaps the most critical issue we face. This keynote will address the solutions that light metals technologies bring to the table to meet these challenges. The opportunities for processing and component manufacture to address these challenges will be reviewed and discussed.
Magnesium Alloys as Biodegradable Implants
Authors: Kannan M. Bobby , Singh Raman R.K.
Published: August 2009

In this study, an attempt was made to enhance the degradation resistance of magnesium alloys for potential biodegradable implant applications through surface treatment. AZ91 magnesium alloy was taken as the test sample and was alkali-treated for two different periods of time and then the in vitro degradation behaviour of the alloy was studied using electrochemical impedance spectroscopy and polarization techniques in simulated body fluid. The study suggests that alkali-treatment reduces the degradation rate in AZ91 magnesium alloy.
Simulation of Flow Field and Particle Trajectory in EB Cold Hearth Melting Process
Authors: Zhang Ying Ming , Pfeifer Herbert , Friedrich Bernd , Zhou Lian
Published: August 2009

Electron beam cold hearth melting process is an efficient method to produce the premium quality titanium alloys, especially to eliminate inclusions. A simulation work was carried out to study the process, concerning the flow field and particle trajectory at three different melt rates. The simulation results show that, when there is an overheat zone near the outlet zone, the molten metal flows to the sidewall of the cold hearth, and from the outlet zone to the inlet zone at the top surface which avoids the inclusion particle flows out the cold hearth. At the bottom of the liquid pool, the fluid flows to the outlet directly along the center plan, which forms a short circuit, decreases the residence time of the inclusion particles; there is a critical density range of inclusion particles, which have more probability to flow out of the cold hearth. The inclusion particles, whose density lower than it, will flow to the sidewall. The inclusion particles, whose density higher than it, will sink into the bottom mushy zone. Both cases let the inclusion have higher probability to eliminate the inclusions.
Research on Titanium Alloys with High Toughness and High Damage Tolerance
Authors: Zhao Yong Qing , Qu Heng Lei , Chen Jun
Published: August 2009

The recent shift in the design focus for aeroplanes from strength to damage tolerance has led to a subsequent shift in the focus of Ti alloy research. China first started to research Ti alloys with damage tolerance from the year 2000. The first product stemming from this research is a Ti alloy with high strength, high toughness and damage tolerance (TC21). TC21 exhibits high strength (UTS  1100MPa), high fracture toughness (K1c  70MPa.m1/2) and a low crack propagation rate (da/dN being similar to Ti-6-4 with  annealing). Another Ti alloy, named TC4-DT, has also been produced. It has moderate strength, along with high toughness and damage tolerance (UTS  900MPa, K1c  70MPa.m1/2, da/dN being similar to Ti-6-4 with  annealing). Both TC21 and TC4-DT are now undergoing rapid development, with the former alloy also being applied to a full scale aeronautical application. Both TC21 and TC4-DT have promising futures in the industry. They will be the main Ti alloys with damage tolerance utilised in the Chinese market.
Utilization of Gneiss in Asphalt Concrete Mixtures
Authors: Wu Shao Peng , Hu De Ming , Pang Ling , Wang Hong
Published: August 2009

Construction of the pavement has consumed a huge amount of high grade aggregates, such as basalt, limestone etc. In some region, these aggregates are very scarce and have to be produced and transported from far aggregate quarries which would cause the waste of energy and resources as well as the increase of cost. Large quantities of gneiss exist in China, the use of gneiss as aggregates might help meet the highway constructing demands and save. In this paper, the feasibility is analyzed with respect to different aspects. Physical properties of gneiss aggregate were evaluated using Los Angeles abrasion, specific gravity and flakiness index. Mixture properties were characterized in terms of Marshall stability, moisture susceptibility, soak wheel track and low temperature cracking resistance property. Experiment results indicate that the physical properties of gneiss aggregates can satisfy the related specifications and these gneiss materials as aggregates can be used in asphalt pavement. Results also show that the optimal gradation component of the mixture consists of the gneiss as coarse aggregate and the limestone as fine aggregate. The use of hydrated lime can improve the moisture susceptibility of the mixtures containing gneiss aggregates.
Densification of Alumina Powder by Using PECS Process with Different Pulse Electric Current Waveforms
Authors: Dang Khanh Quoc , Nanko Makoto , Kawahara Masakazu , Takei Shinichi
Published: August 2009

Densification and sample temperature of alumina (Al2O3) powder during pulsed electric current sintering with different pulse power generators, inverter type and pulsed direct current type were investigated. The sample temperature for inverter generator was higher than that for pulsed direct current generator in same die temperature ranging form 800 to 1400oC. The relative density increased with increasing of the sample temperature.
Experimental Study of Non-Sintering Block for Reducing Surface Temperature Using Recycling Bottom Ash
Authors: Park Jong Bin , Lee Sang Ho , Gee Chae Sung , Pyun Hee Bum
Published: August 2009

Permeable pavement systems are suitable for a variety of residential, commercial and industrial applications because pavements such as water-retentive or water absorbing pavements are helpful to alleviate urban heat island phenomena by reducing pavement temperature, yet are confined to light duty and infrequent usage. And most of study for the permeable pavement is limited to asphalt pavement. Also, immense quantities of coal combustion by-products are produced every year, but only a small fraction of them are currently utilized, particularly bottom ash which is used in this study.
So, in this study, it was intended to develop new permeable and water-absorbing pavement blocks to control pavement temperature and storm water runoff. And mechanical characteristics-compressive strength, porosity etc were carried out. Also, Experiments for thermal environment characteristics and pollution control were carried out in laboratory scale using modified pavement samples. Experimental results indicated that blocks with bottom ash were suited to standard and possessed excellent water-retentive and water purification ability.
Microstructures and Electrical Properties of Random-Oriented (Bi,La)4Ti3O12 Thin Film Deposited by Pulsed-DC Sputtering Method
Authors: Lee M.W. , Ryu Sung Lim , Yeom S.J. , Kweon Soon Young
Published: August 2009

Ferroelectric properties of Lead-free (Bi,La)4Ti3O12 (BLT) films were evaluated on the newly developed MTP (Merged Top-electrode and Plate-line) cell structure. The BLT film was deposited by pulsed-DC sputtering method on a buried Pt/IrOx/Ir bottom electrode stack with W-plug. The BLT composition in the sintered sputtering target was Bi4.8La1.0Ti3.0O12. However, the deposited film composition was about Bi4.0La1.0Ti3.0O12 after the heat treatment of crystallization at 700°C/O2/30sec. And grains of the BLT film were randomly oriented and uniformly small ellipsoidal shape (long direction: ~100nm, short direction: ~20 nm). The remnant polarization (2Pr) and the leakage current density measured in the 100nm-thick BLT film were about 21 C/cm2 and 3 ×10-5 A/cm2 at 3 V, respectively. The fatigue loss was about 10% of the initial polarization value after 1×1011 fatigue cycles.
Synthesis of Ca-Al-Si-O Compounds from Local Wastes
Authors: Sanewirush U.Sangwanna , Saewong P.
Published: August 2009

The local wastes, which are sources of SiO2, Al2O3 and CaO, are rice husk ash, waste sediment from aluminum anodizing process and dreg from pulp production, respectively. The wastes are mixed in three different compositions in ranges of 20-50 SiO2, 20-35 CaO and 20-45 Al2O3, wet milled, slip casted and then fired at 1,100 °C. Characterization of the fired bodies reveals the formation of calcium-aluminosilicate compounds: gehlenite and anorthite as major phases, in accordance with the SiO2-CaO-Al2O3 ternary diagram. Their bulk densities and % water absorption lies between 0.95-1.42 g/cm3 and 37.40-67.95%, respectively. While flexural strength and coefficient of thermal expansion are between 4.09-9.56 MPa and 6.14 - 10.1 x 10-6 °C-1, respectively. By simple thermal conductivity comparison, the materials themselves have thermal conductivity comparable to alumina ceramics. These wastes, therefore, may be used as precursors for the production of some insulating refractory members, in place of minerals from natural resources.
Removal of Particles and Dissolved Metals in Motorway Runoff by Filtration and Adsorption Using the Expanded Polypropylene Media
Authors: Kang Sung Won , Kim Seog Ku , Yun Sang Leen , Oh Hye Cheol , Ahn Jae Hwan
Published: August 2009

This research was conducted to investigate the application of the novel upflow-type filtration device using hydrophobia media made of expanded polypropylene (EPP) from driveways site. The higher level of motorway-derived heavy metal contamination exists in stormwater runoff from a road section and the heavy metal levels were higher than the regulated Korean environmental guideline in lake and river. For Cd, Cr, Cu, Pb and Zn, the influent event mean concentrations (EMCs) during 8 storm periods were 2.75, 37.3, 90.5, 118.5 and 546.5 µg/L, respectively. The novel upflow-type filtration device with main mechanism of filtration and adsorption showed removal (>91%, >93%, >85%, >91% and >80%) of the studied heavy metals (Cd, Cr, Cu, Pb and Zn) and differences of medians of removal efficiencies among heavy metals were not statistically signficant by Kruskal-Wallis test (p>0.05) during 8 storm events. It is found that EPP media is very effective at the removal of the heavy metals, and the magnitude of heavy metal removal in a decreasing order is Cr, Cd, Pb, Cu and Zn.
Development of Eco-Debinding Process Using Supercritical Extraction of Low Molecular Organic Binders in Ceramic Bodies with Nano-Sized Capillary Structure
Authors: Kim Sang Woo , Park Jeong Sik
Published: August 2009

Eco-debinding process using supercritical extraction of low molecular organic binders in nano-porous ceramic bodies was examined. The debinding properties related to structural changes during supercritical extraction and conventional solvent extraction were also compared. The debinding rate of supercritical extraction was significantly enhanced compared to the debinding rate of solvent extraction because of the high diffusivity of the supercritical carbon dioxide for the low molecular weight wax binder in the molded bodies with nano-sized pore structure, although both debinding rates showed same a square root of time dependence. The extraction rates with morphological changes varied depending on the degree of saturation at the end of debinding stages. Both the debinding methods experienced morphological changes with a debinding front separating the pendular state region from the undebinded region with fluid state in low molecular paraffin wax based powder compacts during extraction. The capillary structural changes in the green bodies caused severe defects during extraction and degraded the physical properties. In spite of the abrupt changes of the capillary structure, the debinding defect was significantly alleviated for the supercritical debinded ceramic bodies, compared to the solvent extracted bodies.
Fabrications and Evaluations of Hydrogen Permeation on TiN-5wt%Ni Membrane by Spark Plasma Sintering
Authors: Kim Kyeong Il , Hong Tae Whan
Published: August 2009

Many laboratories have researched membrane for gasification of coal technique, separating hydrogen from fossil fuel. In general, Pd membrane of separating hydrogen is very good a property of hydrogen selectivity on high temperature, but it has some problems, hydrogen embrittlement and costly material. So, we need some materials of good properties about hydrogen selectivity instead of Pd. In this research, we fabricate membrane for hydrogen permeation, that is great in resistance to acids and chemically steady TiN. Our laboratory investigated about hydrogen selectivity. TiN powder is milled 30, 60 and 240 minutes by vibration mill, respectively. After than the samples put in operate spark plasma sintering. We analyze XRD, SEM, BET and TG/DSC. Also, in this research take an inspect hydrogen selectivity by ourselves manufactured Sievert’s type hydrogen permeation membrane equipment.
Thermoplastic Modification to Konjac Glucomannan with Methyl Acrylate
Authors: Luo Xue Gang , Liu Feng , Zhang Zheng Guang , Lin Xiao Yan
Published: August 2009

A novel thermoplastic konjac glucomannan(TKGM) was synthesized with KGM and methyl acrylate(MA) initiated by ammonium persulfate. The percentage grafting (PG) and the grafting efficiency (GE) was affected by concentration of initiator and monomer, temperature, and time. The results indicated that the percentage grafting (PG) and the grafting efficiency (GE) can attach 70% and 90% at optimal conditions, respectively. The structure and properties of TKGM were characterized by FTIR and DSC. FTIR results demonstrated that graft copolymerization was occurred between MA and KGM. The results of DSC indicated that a new glass transition temperature (Tg) of TKGM at 16.4°C was appeared compared with KGM with no glass transition temperature. It suggested that product of TKGM can be made through thermoplastic process.
Reinforcement Design of Poplar Glulam
Authors: Hu Ying Cheng , Cheng Fang Chao
Published: August 2009

Wood is one kind of renewable natural eco-material. Glued laminated timber (glulam) is an engineered wood product made from sawn lumber lamina glued together in horizontal layers. The application of glulam in the construction structure not only has great environmental value, but also reduces energy consumption and carbon emission of the construction. In this study, we evaluated the effects of different factors on the structural properties of glulam and designed several enhancement modes to reinforce the glulam with FRP (Fiber Reinforced Plastic). Then, we measured the mechanical properties of the glulam specimens in the different enhancement modes and selected the optimal reinforcement mode. The reinforcement method obviously increased the value of MOE and MOR of poplar glulam by 5%-15% and 5%-12% respectively. FRP length of 600mm was the optimal and most economic reinforcement length, and finger joint position of 300mm is the optimal position.
Synthesis of Magnetite Nano-Particles and Powder Activated Carbon as a Novel Material for Water Treatment
Authors: Seo Gyu Tae , Kim Jin Tae , Kim Sung Su , Kaewsuk Jutamas
Published: August 2009

The objective of this study is to develop a novel powder activated carbon (PAC) by surface modification with magnetite nano-particles for enhanced removal of NOM in water. The PAC used for experiment was two types, SAC (wood-based) and MAC (coal-based). First the PAC was treated by heat at 650 or 900 °C for 1hr under N2. And then the PAC surface was synthesized with magnetite nano-particles at the same condition. Adsorption tests of NOM were carried out to identify functional characteristics of the surface modified. Despite reduced surface area, adsorption capacity of the surface modified PAC was comparable to the virgin one. However much increased adsorption capacity was obtained by heat treatment of the PACs. SEC and SUVA254 results showed no specific selectivity in removal of NOM by the modification of PAC surface characteristics. Enhanced oxidation of the NOM was also observed by the magnetite nano-particle synthetic PACs in contact with ozone. Conclusively the surface modification of the PAC has high potential as a novel adsorption material for advanced water treatment.
Development of Non-SF6 Strip Casting Process for Mg Alloys
Authors: Jang Dong In , Kim Shae K.
Published: August 2009

For non-SF6 process and melt cleanliness, CaO added AZ31 Mg alloy has been developed for strip casting. Mg alloys were usually ignited during conventional casting, the continuous casting and strip casting. Protective gases should be used in order to prevent the ignition of Mg alloys during melting and casting processes. However, protective gases have the disadvantages of global warming potential, high production cost and corrosion of steel based equipments. To solve ignition problem and overcome environmental issue, this paper discussed the effects of CaO addition and amount on strip casting process in terms of non-SF6 process and melt cleanliness.
The Influence of Sn Addition on the Corrosion Behavior of Mg-5Al-1Zn Alloy
Authors: Park Kyung Chul , Kim Byung Ho , Jeon Jong Jin , Park Yong Ho , Park Ik Min
Published: August 2009

In the present work, the effect of Sn addition on the corrosion behavior of Mg–5Al–1Zn alloys was investigated. Microstructure, potentiodynamic polarization and immersion tests were carried out in 3.5% NaCl solution of pH 7.2 to estimate the corrosion behavior of AZ51 alloys with and without Sn addition. Mg17Al12 and Mg2Sn phases were mainly precipitated in inter-dendrite structures. With increasing the Sn content, the volume fraction of the Mg2Sn phase was increased and coarsening tendency was observed. The corrosion resistance was increased by Sn addition. Especially, the AZ51-5wt.%Sn alloy characterized the superior corrosion resistance among the four alloys. The Sn is known for a high hydrogen overvoltage and the secondary phases effectively formed the network structure, resulting in a drastically decreasing corrosion rate of AZ51 alloy.
Reliability Analysis of the Structural Laminated Veneer Lumber
Authors: Xue Bing , Hu Ying Cheng
Published: August 2009

The structural Laminated Veneer Lumber(LVL) is a kind of high-performance eco-material used in the construction engineering structure. It has great significance to analyze the structural reliability for the design and manufacture of the structural LVL. In this paper, the modulus of elasticity and static bending strength of LVL manufactured by birch and poplar veneers were obtained. And the factors were also analyzed, such as wood species, veneer thickness and LVL density. The advanced first order and second moment method (AFOSM) was used to analyze the reliability of LVL. So this paper offered a method to analyze the reliability of structural LVL for designing and using reasonably.
Effect of Nitrogen Content on the Hot Ductility during Hot Deformation of Stainless Steels
Authors: Liu Jie , Fan Guang Wei , Han Pei De , Liu Jian Sheng , Gao Ji Qiang , Yang Jian Feng
Published: August 2009

Effects of nitrogen content on hot ductility of duplex stainless steels have been investigated. With the increase of nitrogen content in the duplex stainless steels, mechanical strength increased, while hot ductility and elongation decreased. With the same strain rates and deformation degree, the high nitrogen content led to the high optimum hot ductility temperature for the high nitrogen DSS alloy. These results indicated the importance of control over the shape and volume fraction of phases in duplex stainless steels to achieve the optimum hot ductility.
Effect of Warm Processing Parameters on the Precipitation of γ'-Phase in 2205 Duplex Stainless Steels
Authors: Fan Guang Wei , Liu Jie , Han Pei De , Qiao Guan Jun , Yang Jian Feng
Published: August 2009

Effect of the warm processing parameters (the strain rate, forming temperature and deformation degree ) on the γ' metastable phase transformation in 2205 duplex stainless steel has been studied. The γ' metastable phase was located within the ferrite phase. Dynamic recovery took place only within the γ phase, and dynamic recrystallization underwent for the ferrite phase. The γ' metastable phase transformation was affected by the deformation degree and about 15% deformation led to appearance of the γ' metastable phase. γ' metastable phase formation by the precipitation of intragranular γ' was favored by increasing ageing time, and the size and content of γ' metastable phase were related to deformation temperature and strain rates.
Synthesis, Characterization and Electrochemical Performance of Li2Mn0.7Fe0.3SiO4 Prepared from Solid-state Reaction
Authors: Liu Wen Gang , Xu Yun Hua , Yang Rong
Published: August 2009

Li2MSiO4(M=Mn, Co, Ni) is a potential high capacity cathode material because of its outstanding properties that exchange of two electrons per transition metal atom is possible and the theoretical capacity of Li2MSiO4 can reach as high as 330 mAhg-1. In this family, the cathode performance of Li2MnSiO4 synthesized by solution route has been published recently. However, it seems that the cycle life of Li2MnSiO4 fell short of our expectation. In this work, the Li2Mn0.7Fe0.3SiO4 cathode material was synthesized by traditional solid-state reaction method. The prepared powder was consisted of majority of Li2Mn0.7Fe0.3SiO4 and minor impurities which were examined by XRD. FESEM morphology showed that the products of Li2Mn0.7Fe0.3SiO4 and Li2MnSiO4 have similar particle size (about 50-300 nm). The electrochemical performance of Li2Mn0.7Fe0.3SiO4, especially for reversible capacity and cycle life, exhibited better than those of Li2MnSiO4.
In Situ Fracture Behavior of AZ51 and AZT513 Alloy
Authors: Kim Byeong Ho , Park Kyung Chul , Lee Sung Hak , Park Yong Ho , Park Ik Min
Published: August 2009

The fracture behavior of Mg-5Al-1Zn and Mg-5Al-1Zn-3Sn alloy was investigated by direct observation of microfracture process using an in-situ loading stage installed inside a scanning electron microscope chamber. Crack was initiated at the interface of Mg/second-phase particles or second-phase particles. Fracture of the alloys was predominantly dimple or/and quasi-cleavage failure. The improvement of what could be explained by mechanisms of blocking of crack or shear band propagation, formation of multiple shear bands, crack blunting and shear band branching.
Eco-Fabrication of Metal Nanoparticle Related Materials by Home Electric Appliances
Authors: Hayashi Yamato , Inoue Masahiro , Narita Ichitito , Suganuma Katsuaki , Takizawa Hirotsugu
Published: August 2009

Applications of various noble metal nanoparticles were investigated for newly, ecology and economy home electric appliances (microwave, ultrasonic) used system. Noble metal oxides have merit in metal particles fabrication, as one of these example example, there are decomposed by only heating in air. That is, noble metal oxide don't use strong reduction atmosphere. This reduction is ecologically clean, because many noble metal oxides are not toxic and during decomposition O2 is evolved. We have reduced noble metal oxides by microwave and ultrasound, and tried to fabricate noble metal nanoparticles, and investigated various processing. These energy are widely used by home electric appliances. By choosing suitable process and conditions, it is reasonable to expect that home electric appliances ecology and economy fabrications can be extended to obtain simply various noble metal nanoparticles related materials.
Research on Crosslinking of Polylactide Using Low Concentration of Dicumyl Peroxide
Authors: Xu Chang Gang , Luo Xue Gang , Zhuo Xiu Rong , Liang Li Li
Published: August 2009

The effects of dicumyl peroxide (DCP) at low concentrations on initiating cross-linking of polylactide (PLA) by melt blending were investigated. Processing characteristics, morphology, thermal behavior and rheology character of PLA gel were characterized by torque rheometer, XRD, DSC and rotary rheometer. The results showed that the crosslink rate of the blends increased with dicumyl peroxide content increasing. The PLA gel with 0.73 wt% of DCP appeared obvious crystallization behavior and a new crystalline structure maybe formed as DCP was 1.4 wt%. And it was also found that the exothermal peak temperature of PLA gel decreased with increasing dicumyl peroxide content except for the gel with 1.4 wt% of dicumyl peroxide. It also has been inferred by rheology analysis that the blend may be the structure of gel or 3D network, and the melt strength was improved.