bluuebunny/crossref_metadata_2025 huggingface dataset:
A Preliminary Quantitative XPS Study of the Surface Films Formed on Pure Magnesium and on Magnesium-Aluminium Intermetallics by Exposure to High-Purity Water
Authors: Liu Ming , Zanna Sandrine , Ardelean Helene , Frateur Isabelle , Schmutz Patrik , Song Guang Ling , Atrens Andrej , Marcus Philippe
Published: August 2009

An XPS investigation was carried out on the surface film formed by exposure to high-purity water, on mechanically polished Mg and the two Mg-Al intermetallic compounds: Al3Mg2 and Mg17Al12. The result for mechanically polished pure Mg indicates that a film of MgO covered by a Mg(OH)2 layer, formed by the reaction of MgO with water vapour in the air. On immersion in distilled water, this film was hydrated to a duplex film with an inner MgO layer next to the Mg metal and an external porous layer of hydroxide. For both intermetallics, there was preferential dissolution of magnesium from the mechanically ground surface and also during aqueous immersion. After immersion, there was a 10 nm thick, stable film on the surface; the film composition on Al3Mg2 was whilst that on Mg17Al12 was .
ATM: A Greener Variant of High Pressure Die Casting
Authors: Gunasegaram Dayalan R. , Givord Michel , O'Donnell Robert G.
Published: August 2009

ATM high pressure die casting technology (ATM) is a variant of the traditional high pressure die casting (HPDC) process and is distinguishable by its characteristic lean runners that increase process yields. Reduced raw material consumption helps ATM leave a smaller footprint on the environment by lowering greenhouse gas (GHG) emissions during primary processing of the alloys and in their melting and handling in the foundry. Further avenues for reducing GHG emissions are raised by the use of ATM technology which improves the integrity of castings - facilitating the adoption of lighter weight components in automobiles. In the present paper, reductions in GHG emissions achieved by ATM are illustrated with the aid of a commercial case study; potential mass reduction opportunities for the automotive sector are explored with the aid of finite element analysis.
Surface Modification of Metallic Biomaterials for Orthopaedic Applications
Authors: Wang Min
Published: August 2009

Metallic biomaterials such as stainless steel and Co-based alloys are corrosion resistant and possess excellent mechanical properties and hence can be used in load-bearing implants for human tissue repair. However, these materials are bioinert and some of them can cause concerns over their long-term implantation as they release cytotoxic metal ions to surrounding body tissues. Forming a bioactive coating on implantable metals combats these problems and makes these materials very attractive for medical applications. This paper gives an overview of our research work over the past decade on using a number of surface modification techniques (plasma spraying, spraying-and-sintering, ion beam assisted deposition, biomimetic deposition, etc.) to improve the osteoconductivity of metallic biomaterials (Ti, Ti-6Al-4V and NiTi SMA).
In Vitro Cytotoxicity of Binary Ti Alloys for Bone Implants
Authors: Li Yun Cang , Wong Cynthia , Xiong Jian Yu , Hodgson Peter  D. , Wen Cui E
Published: August 2009

Interest in using titanium (Ti) alloys as load-bearing implant materials has increased due to their high strength to weight ratio, lower elastic modulus, and superior biocompatibility and enhanced corrosion resistance compared to conventional metals such as stainless steel and Co-Cr alloys. In the present study, the in vitro cytotoxicity of five binary titanium alloys, Ti15Ta, Ti15Nb, Ti15Zr, Ti15Sn and Ti15Mo, was assessed using human osteosarcoma cell line, SaOS-2 cells. The Cell proliferation and viability were determined, and cell adhesion and morphology on the surfaces of the binary Ti alloys after cell culture were observed by SEM. Results indicated that the Ti binary alloys of Ti15Ta, Ti15Nb and Ti15Zr exhibited the same level of excellent biocompatibility; Ti15Sn alloy exhibited a moderate biocompatibility while Ti15Mo alloy exhibited a moderate cytotoxicity. The SaOS-2 osteoblast-like cells had flattened and spread across the surfaces of the Ti15Ta, Ti15Nb, Ti15Zr and Ti15Sn groups; however, the cell shapes on the Ti15Mo alloy was shrinking and unhealthy. These results indicated that the Mo contents should be limited to a certain level in the design and development of new Ti alloys for implant material applications.
Why Choose Magnesium?
Authors: Abbott Trevor B.
Published: August 2009

The lightness of magnesium makes it an attractive material for applications where weight reduction is critical, in particular, consumer electronics and transportation industries. Despite its advantages as a material the use of magnesium worldwide is a tiny fraction of other materials (steel, plastic, aluminium). Amongst the reasons for this, the metal’s price has not been a significant factor until recently. Throughout the period of 2001-2006, magnesium has been cheaper than both aluminium and zinc on a volumetric basis.
An issue that magnesium presently faces is a perceived insecurity of supply. 77% of primary magnesium is produced within China and the price has seen some enormous shifts. In late 2005 the magnesium price (primary FOB China) was about 1500USD/t. By the third quarter of 2008 it had risen to over 6000USD/t only to fall in recent month to below 3000USD/t.
The current pricing levels of around 3000USD/t could prove beneficial if maintained over a long period, if it led to the establishment of new producers and a diversification of the supply base.
Mechanical Compatability of Nanostructured Titanium with Human Bone
Authors: Cao Peng , Zhang X.N. , Zhang D. L. , Gabbitas Brian
Published: August 2009

With their very low density, excellent biocompatibility, and good mechanochemical properties, titanium alloys have been considered a high-end material for making biomedical devices and instruments. However, they still have some substantial challenges to be overcome. One major problem, which eventually leads to revision surgery, is the implant loosening- a result of tissue migration, formation of wear debris, insufficient interface bonding between bone and implant, and stress shielding. Nanosized features in the material have the potential to provide a solution to these problems. A nanostructured surface is able to not only promote tissue ingrowth, but also increase the surface hardness and therefore improving the wear resistance and enhancing fatigue strength. This paper reports our recent work on how surface treatment on titanium alloys changes their mechanical properties. The mechanism by which the surface nanostructuring alters mechanical properties has also been discussed.
The T5 Heat Treatment of Semi-Solid Metal Processed Aluminium Alloy F357
Authors: Möller Heinrich , Govender Gonasagren , Stumpf Waldo
Published: August 2009

The T5 heat treatment of semi-solid metal (SSM) processed alloy F357 was investigated by considering the effects of cooling rate and natural aging after casting, as well as artificial aging parameters on tensile properties. In addition, the tensile properties of SSM-HPDC F357 in different temper conditions (F, T4, T5 and T6) are compared. The Quality Index (QI) is used to compare the influence of different T5 heat treatment parameters and different temper conditions.
Magnesium Matrix Composites Reinforced with Titanium Particles
Authors: Kondoh Katsuyoshi , Kawakami Masashi , Umeda Junko , Imai Hisashi
Published: August 2009

In fabricating metal matrix composites, it is important to evaluate the coherence at the interface between the reinforcements and the matrix metal. Titanium particulates were selected as suitable reinforcements in this study because they had high hardness and Young’s modulus compared to the magnesium alloys used as the matrix, and also showed better ductility than those of ceramic particles. The wettability in the combination of pure magnesium and pure titanium was investigated in this study. The sessile drop method indicated that the contact angle in the case of Mg-Ti was 40°at 1073K in argon gas atmosphere, and showed an excellent wettability of pure titanium by molten pure magnesium. No intermetallic compound at the interface between them was detected. Titanium particulate could be effective reinforcements of magnesium composite materials. Water-atomized magnesium composite powders including titanium particles were used as raw materials, and consolidated by cold compaction and hot extrusion. When including about 3 mass% Ti particles, the magnesium composites reinforced with them showed significantly improved yield stress and tensile strength, while having good elongation.
Perspectives for Nanostructured Light Metals and Alloys
Authors: Lewandowska Małgorzata , Kurzydlowski Krzysztof Jan
Published: August 2009

Nano-structured metals have attracted growing research interest, which has brought about the development of methods for their fabrication. A number of fabrication methods involve severe plastic deformation, SPD, and involve refinement of the coarse-grained structures to grain sizes on a nanometre scale. Such grain refinement is accompanied by a significant improvement in mechanical strength. The improved properties of the nano-structured metals open up perspectives for their application in innovative industries such as aerospace, surface transport and biomedical implant manufacturing. The advantage of using nano-structured light metals is possible weight reduction of manufactured components. In the case of automotive parts, this may contribute to a reduction in CO2 emissions – one of the most important global challenges – due to the significantly higher strength of nano-structured metals and alloys compared to their microcrystalline counterparts. Nano-structured metals also exhibit high strain rate superplasticity at relatively low temperatures. This offers fast processing of materials, whose superplastic forming would be restricted otherwise. Finally, nano-structured metals also possess improved functional properties such as wear and corrosion resistance, which can broaden the range of applications of engineering metals and alloys even further. This paper reviews recent progress in the development of light nano-engineered metals and alloys. In particular, interest is concentrated on the metals and alloys processed by SPD methods. Conclusions are drawn with regard to future development of light materials for application in transport.
Nucleation and Growth during Reactions in Accumulative Roll Bonding of Ti/Al Multilayers
Authors: Yang Deng Ke , Hodgson Peter  D. , Wen Cui E
Published: August 2009

A two-stage process in the formation of TiAl3 was found in the accumulative roll bonding (ARB) Ti/Al multilayers. The distribution of layer spacing did not become broad enough to lose the main features of the double exothermal behaviour. A modified model based on thin films was set up to describe the kinetic characteristics of the formation of TiAl3 in ARB samples
Influence of SiC Particles on the Grain Refinement of an Mg-Al Alloy
Authors: Schiffl Andreas , Easton Mark
Published: August 2009

SiC particles are effective grain refiners in Mg-Al alloys. Several investigations, from different researchers, into their effect on a range of alloys with different Al contents has been undertaken and it has been found that the greatest reduction in grain size occurs in alloys having low Al contents. Performing grain refinement studies on a range of alloy contents also allows for further investigation into the mechanisms of grain refinement. It was found that the size of the SiC particles is also important in magnesium grain refinement. However, the presence of Mg2Si in the microstructure and the consideration of phase equilibria suggest that SiC can transform into other binary or ternary carbides. If such carbides are formed, they may also act as an effective grain refiner for Mg-Al alloys. In this study, the possibility of formation of new carbides (Al4C3, Al2MgC2, Mn7C3, Mg2C, Mg2C3, Al2CO etc.) and their ability to be good grain refiners for Mg-Al alloys is discussed.
On the Creep Resistance of HPDC Mg-RE Based Alloys
Authors: Zhu Su Ming , Gibson Mark A. , Nie Jian Feng , Easton Mark , Bettles C.J.
Published: August 2009

This paper presents an analysis, based on microstructural observations by transmission electron microscopy, of the influence of chemical composition on creep resistance of high pressure die casting (HPDC) Mg-4RE-0.6Zn alloys. The improved creep resistance, by increasing the Nd/La ratio of the rare earth (RE) mixture, is shown to be associated with the supersaturation of Nd solute in the -Mg matrix, evidenced by the formation of Nd-rich precipitates on dislocations after a thermal ageing treatment. The result indicates that solid solution/precipitation strengthening of the -Mg matrix is important to the creep resistance of HPDC Mg-RE based alloys.
Influence of Strontium, Silicon and Calcium Additions on the Properties of the AM50 Alloy
Authors: Fechner Daniel , Blawert Carsten , Hort Norbert , Kainer Karl Ulrich
Published: August 2009

The increasing use of heat resistant magnesium alloys for automotive applications is expected to influence the chemical composition of upcoming post consumer scrap. Therefore it would be useful to define alloys that resemble the future composition of the material. For this purpose a matrix of potential recycling systems has been set up. AM50 was used as a base material to which decisive amounts of strontium, silicon and calcium were added. The basic heat resistant alloy systems AJ, AS, and AX have been investigated closely. This work deals with combinations of the three above mentioned elements. Some essential observations shall be presented concerning the development of the microstructure and its influence on the materials properties. For combined additions of strontium, silicon and calcium the formation of a new ternary phase has been observed. The compound has a positive influence on the fracture elongation and the corrosion rate in the salt spray test.
Twin-Roll Cast Al-Clad Magnesium Alloy
Authors: Prasada Rao A.K. , Kim K.H. , Bae J.H. , Bae Geun Tae , Shin Dong Hyuk , Kim Nack J.
Published: August 2009

An attempt has been made to clad Mg alloy with Al by twin-roll casting. This was done by inserting an Al sheet between the roll and the Mg alloy melt during twin-roll casting. Microstructural investigation across the transverse section of the as-cast Al-clad Mg alloy sheet reveals a very good interfacial bonding between Al and the base Mg alloy. Annealing of the Al-clad Mg alloy sheet results in the formation of layers of various intermetallic phases along the Mg/Al interface. Subsequent rolling of the as-annealed sheet significantly improves the formability of the reaction zone, as evidenced by the cracking of the base Mg alloy before the cracking of the reaction zone.
Corrosion of AZ91 - Influence of the β-Phase Morphology
Authors: Zhao M.C. , Uggowitzer Peter J. , Liu M. , Schmutz Patrik , Song G. , Atrens Andrej
Published: August 2009

The influence of the microstructure, particularly the morphology of the β phase, on the corrosion of Mg alloys has been studied using AZ91 as a model alloy and compared with the corrosion of pure magnesium, used as a standard for comparison. The concentration of the impurity element Fe was below the limit evaluated from theoretical phase diagram construction. Corrosion was measured using hydrogen evolution measurements and some polarization measurements. Corrosion behaviour was characterized for four different microstructures produced by heat treatment of as-cast AZ91: namely (i) as-cast, (ii) homogenization anneal (for 5h and 10h at 380°C), (iii) solid solution and (iv) solution treated and aged. The influence of microstructure can be understood from the interaction of the following three factors: (i) the surface films, (ii) micro-galvanic corrosion acceleration dependant on the amount and distribution of the second phase (the  phase in AZ91) and (iii) the second phase can act as a corrosion barrier and hinder corrosion propagation in the matrix, if the second phase is in the form of a continuous network. It is expected that these factors are important for all multi-phase Mg alloys because all known second phases have corrosion potentials more positive than that of the -phase. The electrochemical measurements did not give good values for the corrosion rate in agreement with the literature.
Microstructural and Mechanical Properties of Titanium Matrix Composites Reinforced with Nano Carbon Materials via Powder Metallurgy Process
Authors: Kondoh Katsuyoshi , Threrujirapapong Thotsaphon , Umeda Junko , Imai Hisashi , Fugetsu Bunshi
Published: August 2009

Powder metallurgy (P/M) titanium matrix composite (TMC) reinforced with multi-wall carbon nanotube (MWCNT) was prepared by spark plasma sintering (SPS) and hot extrusion process, where the powder surface was coated by un-bundled CNTs via wet process. The microstructure and mechanical properties of P/M pure titanium and reinforced with CNTs were evaluated. The distribution of CNTs and in-situ formed titanium carbide (TiC) compounds during sintering was investigated by optical and scanning electron microscopy (SEM) equipped with EDS analyser. The mechanical properties of TMC were significantly improved by adding a small amount of CNTs. For example, when employing the pure titanium composite powder coated with CNTs of 0.35 mass%, the increase of tensile strength and yield stress of the extruded TMC was 157 MPa and 169 MPa, respectively, compared to those of extruded titanium materials with no CNT additive. Fractured surfaces of specimens were analysed by SEM, and the uniform distribution of CNTs and TiC particles, being effective for the dispersion strengthening, at the surface of the TMC were obviously observed.
Thermomechanical Consolidation of Ti/Al/Cr Composite (Composition: Ti-47Al-2Cr (at %)) Powders
Authors: Nadakuduru Vijay , Zhang De Liang , Cao Peng , Gabbitas Brian
Published: August 2009

The present study aims to develop a process to make ultrafine grained (UFG) Ti-47Al-2Cr (at %) alloy using elemental Ti, Al and Cr powders. The process involves mechanical milling of a mixture of the elemental powders to produce a Ti/Al/Cr composite powder, compaction of the milled powder, and consolidation of the powder compact using hot isostatic pressing (HIP) or powder compact forging. This paper is to give an overview of microstructure and the mechanical properties of the alloy samples obtained using the above processing technique. Inhomogeneous microstructures with high amounts of (α2) Ti3Al phase, along with, elemental Ti, were observed in some samples. An attempt has been made to explain the formation of (α2) Ti3Al, and elemental Ti, in the alloy and the processing conditions appropriate for the specific alloy are also discussed.
Shearing Behaviour and Texture Evolution in Aluminium Sheet Deformed by Accumulative Roll Bonding
Authors: Lau K.D. , Quadir M. Zakaria , Ferry Michael
Published: August 2009

Accumulative Roll Bonding (ARB) is a severe plastic deformation technique for producing ultra-fine grain structures in sheet metal. In this investigation, the through-thickness shear strain distribution during single pass rolling of roll-bonded aluminium sheets was monitored via the deflection of an embedded scratch on the through-thickness, pre-polished surface of the material. It was found that, near the sheet surface and at its mid-thickness, rolling generated severe and moderate shearing, respectively. Such shearing was found to have a strong influence on the microstructure and crystallographic texture of the material, which was eliminated during subsequent rolling cycles. Compared to the core of a given rolled layer, both the microstructure and texture at the interface of the layers was inhomogeneous.
The Ablation Casting Process
Authors: Grassi John , Campbell John , Hartlieb Martin , Major Fred
Published: August 2009

A new patented casting process is described, based on a precision aggregate mold, bonded with a water-soluble binder. For the first time the twin functions of the mold (i) defining shape and (ii) providing cooling have been successfully separated allowing the production of castings of all sizes and shapes (thin and thick walls) for all Al and Mg alloys. Because solidification and cooling are separately controlled by the application of water a number of advantages follow immediately. The mold is ablated (i.e. eroded) away by the water without fume or dust and the ‘air gap’ is eliminated by direct contact with the water, enhancing the rate of solidification to levels normally unattainable, resulting in significantly enhanced properties. The unusual microstructures of Al-Si alloys having large DAS but micron-sized eutectic silicon indicates, in agreement with earlier predictions, that DAS per se does not control strength or ductility. The process is currently proving itself in commercial operation, having the additional advantages of modest start-up and tooling costs as well as low competitive piece part costs because of the use of low cost materials and the recycling of aggregate and water.
Development of Aluminium Alloys for High Temperature Applications in Diesel Engines
Authors: Kasprzak W. , Emadi Daryoush , Sahoo Mahi , Aniolek Maria
Published: August 2009

Rapid penetration of diesel engines is expected in North America because of their better fuel efficiency and lower greenhouse gas (GHG) emissions. Diesel engine components, particularly cylinder heads, are made of cast irons and replacing them with aluminium alloys could result in a significant weight reduction and consequently better fuel efficiency. Aluminum alloys for diesel engine applications need to withstand higher operating temperatures and pressures as compared to conventional 3xxx based alloys that lose strength above 150oC. This paper presents selected results pertaining to alloy development with improved high temperature performance based on the modified 356 composition. Such alloys with engineered chemical composition and properly designed heat treatment could have improved properties at temperatures up to 250oC. The advanced thermal analysis techniques including dilatometer analysis were used to determine the effect of alloying additions on thermal characteristics including aging kinetics and its impact on casting service performance. Selected structure analysis results including XRD and TEM/EDX as well as elevated temperature tensile testing are presented.
Electron Beam Processing of Aluminium Alloys
Authors: Yu Peng , Qian Ma , Tomus Dacian , Brice Craig A. , Schaffer Graham B. , Muddle Barry C.
Published: August 2009

Electron beam (EB) direct manufacturing is an additive near-net shape digital fabrication process developed recently. The process offers a promising route for the fabrication of intricate speciality aluminium alloy parts for aircraft and aerospace applications because of the excellent energy coupling between an electron beam and aluminium. As part of a fundamental study on EB manufacturing of Al alloys, this work investigates the effect of the EB processing parameters on the development of the molten pool and the solidification characteristics of Al 2219 and Al 6061 alloys. The samples were processed using a 50kV electron beam gun over a wide range of beam currents (10-40mA) and welding speeds (0.3-0.86m/min) in both the static and oscillation focus modes. In the static focus mode, the molten pool is wedge-shaped; while in the oscillation focus mode, the molten pool is hemispherical, wider and shallower. In both cases, the depth and width of the molten pool increase with increasing beam current but they are less affected by the moving speed of the EB gun in the range 0.3-0.86m/min. Electron beam re-melted and subsequently re-solidified Al 2219 and Al 6061 alloys show microstructural features distinct from those obtained under sand casting and direct chill casting conditions. In particular, fine intermetallic precipitates in the size range 100-200nm are prominent in the equiaxed grains formed in the re-solidified weld beads of Al 6061 compared to the coarse intermetallic particles up to 10m in size prior to EB processing. EB processing offers opportunities for aluminium alloy development.
Friction Stir Processing: A Technique for Microstructural Refinement in Metallic Materials
Authors: Lathabai Sri , Migeon R. , Tyagi V.K. , O'Donnell Robert G. , Estrin Yuri
Published: August 2009

Friction stir processing (FSP) combines frictional heating and severe plastic deformation to produce microstructural modification, either locally targeted at the near-surface regions or through the bulk, of metallic components fabricated by conventional processing routes. In this paper, we highlight the capabilities of this process by applying it to a high-pressure die cast Al-Si-Mg-(Cu) alloy and examining the resulting microstructure and mechanical properties.
Formation of Aluminium Nitride during Sintering of Powder Injection Moulded Aluminium
Authors: Kent Damon , Schaffer Graham B. , Qian Ma , Liu Zhen Yun
Published: August 2009

A TEM study of aluminium nitride formed during sintering of powder injection moulded aluminium under nitrogen is presented. A polycrystalline layer consisting of fine, rod-shaped crystallites of hexagonal AlN formed on the Al powder surfaces. The grain boundaries exhibit a double layer of AlN separated by a thin layer of Al. The structure of the AlN is characterised and its influence upon sintering discussed.
The Influence of Heat Treatment and Plastic Deformation on the Bio-Degradation of a Mg–Y–RE Alloy
Authors: Gunde Petra , Furrer Angela , Hänzi Anja C. , Schmutz Patrik , Uggowitzer Peter J.
Published: August 2009

Magnesium has become an interesting candidate in the field of bioabsorbable implant materials; it is an essential element in the human body, biocompatible and degradable due to its low corrosion resistance in a pH range below 11.5. However, in the human body (pH  7.4) a magnesium implant might degrade too quickly and lose its mechanical strength before the tissue has fully healed. However, the corrosion resistance can be improved for example by the choice of a suitable Mg alloy containing corrosion-inhibiting elements such as yttrium or by the deployment of surface heat treatments at high temperatures causing protective oxide layers to form.
We studied the bio-degradation behaviour of a Mg–Y–RE alloy in different heat treatment states by electrochemical impedance spectroscopy and immersion testing in simulated body fluid. The heat treatments caused a change in microstructure and also the formation of a thermal oxide layer on the sample surface, which consisted mainly of Y2O3 and which slowed the degradation and increased the polarisation resistance significantly compared to the polished state. However, in some specimens localised corrosion attacks occurred which drastically weakened the protective effect of the oxide. Because the implant might be deformed during implantation resulting in the oxide cracking, we intentionally strained the samples and investigated the degradation performance. These cracks led to a decrease in polarisation resistance compared to the non-strained oxidised state, but in comparison to the polished state they still perform better. Macroscopically, the degradation process occurred in a homogeneous way without localised corrosion attacks. Microscopically, corrosion attacks started at the cracks and undermined the oxide layer with time.
Design Strategy for Microalloyed Ultra-Ductile Magnesium Alloys for Medical Applications
Authors: Hänzi Anja C. , Sologubenko Alla S. , Uggowitzer Peter J.
Published: August 2009

The aim of this article is to describe the design strategy deployed in developing new bioabsorbable Mg–Y–Zn alloys. The development approach is based on a microalloying concept, which aims to restrict grain growth considerably during alloy casting and forming. We discuss the efficiency of the design approach, and evaluate the characteristics of the new alloys using metal-physical experiments, thermodynamic calculations, and TEM analysis. Our results show that after extrusion the alloys have very fine grains (<10m), exhibit high ductility (uniform elongation: 17–20%) at considerable strength (ultimate tensile strength: 250–270 MPa), and reveal the presence of finely distributed intermetallic particles, which are stable upon annealing. Due to an attractive combination of mechanical, electrochemical and biological properties, the new alloys are very promising not only for applications in medicine but also in other fields.
High Pressure Coolant Application in Milling Titanium
Authors: Palanisamy Suresh , Townsend Dean , Scherrer M. , Andrews Robert , Dargusch Matthew S.
Published: August 2009

Removal of heat from the cutting zone is critical when machining titanium. The application of high pressure coolant during turning of titanium results in longer tool life and better surface finish. In this paper, the effect of the application of cutting fluid at high pressure during the milling of titanium alloys is presented.
A Method of Preparing Grinding Medium of White and High Performances Using Natural Bauxite Ore
Authors: Han Jun , Wu Bo Lin , Wu Shao Peng
Published: August 2009

This text contrapose on the contradiction between price of alumina powder material and performance of alumina ceramic manufacture at present. Abundant natural bauxite mineral in China as main raw materials was used through the favorable craft course and a small amount of other auxiliary additive to produce grinding medium which have the character of color white, higher performances, lower sintered temperature, fewer consume of resources, cheaper production cost, etc. And the problem of producing high-level grinding medium only using expensive industrial alumina powder was solved and pollution in production of alumina powder was avoided. So the environmental pollution and energy consuming can be reduced and high added value of bauxite can be achieved through this method. The experimental design continued to use the industrial production route and apt to realize industrialization, once it is put into production, enormous social effect will be achieved.
Lignin-Quaternary Adsorbent: Synthesis, Characterization and Application for 2, 4, 6-Trinitrotoluene (TNT) Adsorption
Authors: Zhuo Xiu Rong , Luo Xue Gang , Lin Xiao Yan , Xu Chang Gang
Published: August 2009

A lignin-quaternary adsorbent was made from lignin after phenolization and then amination. As-prepared adsorbent was characterized by SEM, IR and DMA. Effects of adsorbent dose, initial pH and concentration on 2, 4, 6-Trinitrotoluene (TNT) removals from aqueous solution by adsorption of this adsorbent were comprehensively investigated. IR spectra showed that the product comprises quaternary ammonium groups in the form of ether bond. The mechanical strength of the adsorbent is enhanced by combining of PVA. It was possible to remove 66% of TNT from aqueous solution with 0.1 g of the adsorbent under certain conditions (100 mg/L and 25 °C). The results indicated that the amount of TNT adsorbed onto the adsorbent increased with increasing initial concentration; however, it decreased with an increase in pH. The adsorption process was determined to be consistent with the Langmuir isotherm.
The Optimum Design of Production Technology of the Poplar LVL
Authors: Zhang Li , Hu Ying Cheng , Chen Peng , Hu Jian Peng , Yuan Fei Pin , Li Qing , Zhang Mi
Published: August 2009

In this paper, the production technology of laminated veneer lumber was optimized by using the uniform design method. The effects of production technology, such as the press duration, the press temperature, the press pressure and the adhesive spread, were found statistically significant on some mechanical properties of LVL. So in this paper, the thickness of LVL board was a fixed value, but the press duration, the press temperature and the adhesive spread were variable. The modulus of elasticity (MOE) and static bending strength (MOR) as predicted by the ANN approach and the regression functions were compared with the experimental values. It was shown that the proposed neural network model was able to predict valuable mechanical properties, such as the modulus of elasticity and static bending strength, that would facilitate the development of optimum design of properties for manufacturing high quality materials.
Effect of Calcium on Solidification Behavior of Mg-Sn Based Alloys
Authors: Kim Dae Guen , Son Hyeon Taek , Lee Jae Seol
Published: August 2009

The effect of Ca addition on microstructure change, precipitation behaviours and mechanical properties, in the present work, of Mg-Sn based alloys were investigated. With increasing of Ca additions, size of the Mg-Sn-Ca ternary phases (A-type) with fine needle shape was decreased and volume fraction of these phase were increased. As Ca was increase from 1 wt.%, 2 wt.%, size and volume fraction of Mg2Sn with coarse needle shape phase (B-type) was increased. However, in 3 wt.% Ca containing alloy, size of these Mg2Sn phase was smaller than that of 2 wt% Ca addition alloy and volume fraction of these phase was decreased.
A Study on the Formability of AZ31B Magnesium Alloy Sheet with Experiment and Simulation
Authors: Song Jung Han , Lee Geun An , Lee Hye Jin , Lee Nak Kyu , Kim S.H. , Kim K.T. , Park K.D. , Jang J.H.
Published: August 2009

This paper is concerned with formability of AZ31B magnesium alloy sheets at various temperatures. In order to acquire the forming limit curve for quantifying the formability of the magnesium alloy sheet, hemispherical punch forming tests are performed under various temperatures. The initial shape of the blank is rectangular and six different types of specimens are used with their length along the rolling direction of 175mm and widths along the transverse direction of 25, 50, 75, 100, 120 and 175mm. With the equipment of on a SIMADZU 100-ton universal testing machine, hemispherical punch forming tests are performed and a forming limit diagram is constructed at the temperature of 100°C, 200°C and 250°C. FE analyses of hemispherical punch forming tests are also conducted by considering ductile failure model in order to compare the forming limit curve obtained from the experiment and numerical analysis. The comparison examines problems in the current material model and it suggests a future research direction.
Evaluation on Solar Heat Reflective Coatings to Reduce Asphalt Concrete Temperature
Authors: Chen Zheng , Wu Shao Peng , Chen Mei Zhu , Wang Jin Gang
Published: August 2009

As the development of civil construction, the heat island effect in large cities of China has gradually become a social issue. Pavements, especially asphalt pavements, are considered to be one of the main causes of the heat island effect as they cover wide area of cities. In some regions, the surface of asphalt pavements can even be heated up to more than 70°C by solar irradiation in summer times due to the excellent heat-absorbing property of asphalt concrete. In this paper, a solar heat reflective coating on asphalt pavement was investigated to reduce asphalt pavements temperature and mitigate the heat island effect. A solar heat reflective coating was synthesized with certain component contents of resin, pigments, fillings and additives on the basis of the principles of heat reflection. The surface temperatures of the concrete covered by solar heat reflective coating and the reference were compared. Meanwhile, an accelerated loading test with loaded vehicles was performed for these two asphalt concretes. The influence of the reduction in the surface temperature on the air temperature was simulated. The research results indicate that the solar heat reflective coating can obviously reduce the surface temperature of asphalt concrete for its high light-reflection rate in the infrared and visible wavelength region. Furthermore, the accelerated loading test also suggests that this coating improves the rutting resistance of the asphalt concrete compared to the reference when exposed to the same irradiation strength. Therefore, this solar heat reflective coating on asphalt pavement could be adopted as a countermeasure against the heat island effect.
Effect of Final Annealing Temperature on Antibacterial Precipitate of Copper-Bearing Ferritic Stainless Steel
Authors: Zou De Ning , Zhang Yan , Han Ying , Zhang Wei
Published: August 2009

In order to keep the steel with outstanding antibacterial characteristics, the relationship between the anneal temperatures and the amounts of the precipitated Cu-rich phase was investigated in this work. The SEM analysis of annealing specimens indicated that the microstructure changed with the increase of annealing temperature. At 900°C, the martensite phase appeared along the crystal boundary, but the amount of Cu-rich phase was almost no change. At 920°C, the sizes of the Cu-rich precipitates minished and the amounts of the precipitates reduced gradually. At 940°C, there was only martensite phase existing in the ferrite matrix. Therefore, the optimal final annealing temperature range was chosen from 880°C to 900°C to ensure attaining excellent antibacterial properties and favorable mechanical characteristic of copper-bearing stainless steel.
Characterization of Power Plant Bottom Ash and its Application to Cement Mortar
Authors: Kwon Woo Teck , Kim Byung Ik , Kim Y. , Kim Soo Ryong , Ha Sang Wook
Published: August 2009

In this work, the physical & chemical properties of bottom ash generated from power plant are analyzed. Characteristic mortar property and thermal conductivity for building material were investigated with content of added bottom ash. According to the analytic result of bottom ash, chemical compositions of bottom ash is similar to those of fly ash and compressive strength after 7days related to pozzolanic activity shows 2.5N/cm2 and it is confirmed that bottom ash possess a certain amount of moisture activity. Although the fluidity of cement mortar is rapidly decreased with increasing addition of bottom ash, compressive strength for 3 and 7days is increased. The thermal conductivity is not sensitive to the addition of bottom ash.
Synthesis of Zeolite Added Clay and Sewage Sludge
Authors: Yoo Yeong Seok , Cheon Kyeong Ho , Lee Jae Ik , Ban Hyo Jin , Seo Gyu Tae
Published: August 2009

Zeolite has been used as catalyzer, absorbent, ion-exchange matter and dehydrating agent due to its excellent catalytic property and ion-exchange. In recent years, many studies have been conducted to apply zeolite as new materials such as zeolite membranes and zeolite sensor films. To introduce properties of zeolite, it should be examined how zeolite could be reacted other materials. In this study, it is investigated whether zeolite is successfully synthesized or not when clay and/or sewage sludge coexist with zeolite precursor. Zeolite precursor was made of liquid sodium silicate and sodium aluminate. Mixing ratio of caly and/or sewage sludge is 0-10%(wt.). To compare two processes, the mixture was synthsized by hydrothermal method and high temperature sintering process. It is synthesized by hydrothermal with sintering at high temperature process. The resulting materials were characterized by XRD and SEM. As a result, various type of zeolite such as zeolite X, zeolite A and zeolite P1 was successfully synthesized by hydrothermal method when clay and/or sewage coexist with zeolite precursor. However, zeolite was rarely synthesized by high temperature sintering process. Therefore, when preperation of zeolite material mixed with other material such as clay and sewage sludge, hydrothermal method is more effective than sintering at high temperature process.
Synthesis of Silicon Carbide Powders from Iron Tailings
Authors: Zhang Xiao Meng , Xu Li Hua , Hao Hong Shun , Yang Jian Ying , He Fang
Published: August 2009

Silicon carbide powders were prepared by the carbothermal reduction method. The starting powders used were iron tailings and graphite. The XRD results showed that the main crystal phase was SiC and the main impurity was FexSiy in as-fabricated silicon carbide. The SEM results revealed that the grains of SiC-phase in as-fabricated silicon carbide were flaky-like or globular-like. It is found that the carbon addition and the reaction temperature play a key role to obtain SiC-phase, while the holding time and argon flow rate had a little effect on the yield of SiC as the excessive carbon addition are used. The optimum sintering temperature, holding time, argon flowing rate, the ratio of n(C): n(SiO2) are 1500 °C, 8 h, 0.6 L/min, 5:1, respectively.
Key Technology for Extraction, Thermoplastic Modification and Application of Lignin
Authors: Luo Xue Gang , Lin Xiao Yan , Liu Feng
Published: August 2009

New technique has been used to extract of lignin by adding carboxylic acid derivates and organic solvent to precipitate and extract lignin from black liquor (pulp wastewater). Through this new treatment process, new carboxylate which is decomposed to carbondioxide, water and metal oxide at the high temperature was formed. The process of using organic carboxylic acid and organic solvent to precipitate and extract lignin is low-cost and can not cause second pollution. The lignin obtained through this new process is water insoluble and thermoplastic. Its weigh average molecular weight, purity, and glass transition temperature are higher than 2000, 90% and 150°C, respectively. Through the methods of thermoplastic modification, the thermoplastic properties for high purity lignin-based composite materials are improved significantly. Its melt flow ratio, tensile strength and elongation at break are 0.73 g/10 min, 11.8 MPa, and 21%, respectively. Thermoplastic lignin-based composite materials have good processing properties as well as synthetic polymers for extruding, injection molding, and blowing processes. Lignin, as a kind of natural thermoplastic polymers with good processing properties, can be carried out to process for film, foam, and thermoplastic composite.
Influence of CdZnTe/Au Contact on the Wire Bonding Property between the Down-Lead and Au Electrode
Authors: Fu Li , Ren Jie , Nie Zhong Ming
Published: August 2009

According to the need to make high quality X-ray or γ-ray detectors made by high resistance CdZnTe, the wire bonding technology between the Au contact layer of CdZnTe wafer and the down-lead has been studied in this paper. The influence of welding parameters and surface treatment of CdZnTe wafer on the welding quality between Au contact layer and down-lead have been discussed in detail, such as chemical and mechanical polishing technology of CdZnTe wafer before welding, thickness of the contact layer of CdZnTe wafer, welding energy, welding pressure, welding time, and etc. The results showed that the successful jointing between Au contact layer of CdZnTe and down-lead can be achieved when applying the suitable welding parameters and pretreatment technology of CdZnTe wafer. The optimized welding parameters for CdZnTe wafer were as follows: welding power 2w, welding pressure 60×10-3 kg, welding time 20ms and the power for fire ball formation 1.5w.
Material Research of Eco-Product Design
Authors: Yang Xian Yi , Liu Yang , Zhen Yu
Published: August 2009

During the last thirty years people have continued to poison the planet with pesticides and other toxic chemicals, which has led to the destruction of ecosystems and the extinction of many species. More recently people have realized that they too are now threatened by human actions. The ultimate design challenge of the twenty-first century is to avoid or minimize the adverse impacts of all products on the environment. Material as the basis of the product can not be neglected. Like all challenges, this constitutes both a demand and an opportunity - to steer the debate on more sustainable patterns of production and consumption.
Fabrication and Characterization of AZ91/CNT Magnesium Matrix Composites
Authors: Park Yong Ha , Park Yong Ho , Park Ik Min , Oak Jeong Jung , Kimura Hisamichi , Cho Kyung Mok
Published: August 2009

Carbon Nano Tube (CNT) reinforced AZ91 metal matrix composites (MMC) were fabricated by the squeeze infiltrated method. Properties of magnesium alloys have been improved by impurity reduction, surface treatment and alloy design, and thus the usage for the magnesium alloys has been extended recently. However there still remain barriers for the adaption of magnesium alloys for engineering materials. In this study, we report light-weight, high strength heat resistant magnesium matrix composites. Microstructural study and tensile test were performed for the squeeze infiltrated magnesium matrix composites. The wear properties were characterized and the possibility for the application to automotive power train and engine parts was investigated. It was found that the squeeze infiltration technique is a proper method to fabricate magnesium matrix composites reducing casting defects such as pores and matrix/reinforcement interface separation etc. Improved tensile and mechanical properties were obtained with CNT reinforcing magnesium alloys
Influence of SO3 Content on Drying Shrinkage Cracking Resistance of Cement-Fly Ash Stabilized Crushed-Stones
Authors: Chen Xiao , Zhou Ming Kai , Fan Zhi Yong
Published: August 2009

The cement-fly ash stabilized crushed-stones are prepared with different cements, which SO3 contents are 1.8%,2.6%,3.4%,4.2%,5.0%,5.8% and 8.8%，and their 28d splitting strengths, 28d resilient modulus’s, expansion -shrinkage and dry shrink anti cracking coefficients are studied. On these bases, the influence of SO3 content of cement on shrinkage cracking resistance is analyzed. The mechanism of compensating shrinkage by micro expansion in pavement base and the function of SO3 on cement-fly ash binder are also explored in paper. It is proved that the increase of SO3 content in a suitable scope (1.8%-5.8%) can improve the drying shrinkage cracking resistance of cement-fly ash stabilized crushed-stones when the content of fly ash is 10%。But the structure and the performance of materials will be destroyed if the SO3 content of cement increases excessively (>8.8%).
Porous TiO2 Layer Encapsulated Silicon as the Anode Material for Lithium Secondary Batteries
Authors: Kim Bo Eun , Park Sang Eun , Lee Sang Wha , Lim Jong Choo , Cho Byoung Won , Lee Joong Kee
Published: August 2009

The porous TiO2 layer on the silicon surface not only acts as a buffer layer to relieve the strain associated with the volume expansion but also prevents the aggregation of the particles upon normal cycles of charging and discharging. The control of the optimum amount of catalyst has led to enhance the cycle performance of TiO2 coated silicon anode.
Effect of CaO Addition on High Temperature Tensile Properties of Mg Casting Alloys
Authors: Seo Jung Ho , Kim Shae K.
Published: August 2009

The microstructure, hardness and tensile properties of Mg-3Al, Mg-3Al-1.2Ca(AX31), Mg-3Al-1.2CaO(AO31), Mg-9Al, Mg-9Al-1.2Ca(AX91) and Mg-9Al-1.2CaO(AO91) alloys were investigated to identify the effect of CaO addition compared with Ca addition. The results show that the alloy element CaO has a good effect on high temperature tensile properties and CaO added alloys have superior high temperature performance compared with Ca added alloys. Addition of CaO results in the precipitation of Al2Ca phase (C15 phase) on the grain boundaries. This phase precipitated by the reduction of CaO leads to the refinement of a microstructure and improvement of tensile properties at elevated temperature similar to the Ca added Mg alloys. When added into molten Mg Ca makes solid solution in the Mg matrix up to 0.8wt %. But in case of CaO addition the thermally stable compound is precipitated directly without making solid solution with Mg matrix. Therefore, the high temperature tensile properties of CaO added Mg casting alloys are better than Ca added one at the same adding contents (1.2wt.%).