bluuebunny/crossref_metadata_2025 huggingface dataset:
Semiconductor-Mediated Photocatalysed Degradation of Various Pesticide Derivatives and Other Priority Organic Pollutants in Aqueous Suspensions
Authors: Bahnemann Detlef Werner , Muneer M. , Qamar M. , Rahman M.A. , Singh H.K.
Published: March 2009

The photocatalysed degradation of various selected pesticide derivatives, namely N,NDimethyl- a-phenyl benzene acetamide (Diphenamid) [1], 1,2-diethyl phthalate (DEP) [2], 5-bromo- 3-sec.butyl-6-methyl uracil (Bromacil) [3], 3-tert-butyl-5-chloro-6-methyluracil (Terbacil), 2,4,5- tribromoimidazole (TBI) [4], Methoxychlor, Chlorothalonil and Disulfoton [5] as well as that of two selected priority organic pollutants, namely benzidine and 1,2-diphenyhydrazine (DPH) [6], has been investigated in aqueous suspensions of titanium dioxide (TiO2) under a variety of conditions. The degradation was studied by monitoring the change in substrate concentration employing UV spectroscopic analysis or HPLC technique and the decrease in total organic carbon (TOC) content, respectively, as a function of irradiation time. The degradation kinetics was studied under different
conditions such as reaction pH, substrate and photocatalyst concentration, type of photocatalysts and the presence of alternative additives such as H2O2, KBrO3 and (NH4)2S2O8 besides molecular oxygen. The degradation rates and the photonic efficiencies were found to be strongly influenced by the above parameters. A toxicity test was performed for irradiated samples of few selected systems
measuring the luminescence of bacteria Vibrio fischeri after 30 minutes of incubation.
Effect of Organic Additives in Electrolytes for Rechargeable Lithium/Sulfur Battery
Authors: Kim Jin Kyu , Choi Jae Won , Kim Yeon Hwa , Kim Jong Uk , Ahn Jou Hyeon
Published: March 2009

The effect of mixed electrolytes and organic additives on the electrochemical
performance of rechargeable lithium/sulfur battery is investigated. The mixture of organic electrolytes, DME, DIG, TEGDME, and DIOX, was prepared to have appropriate composition, and to the electrolyte were added various organic additives, such as toluene, γ-butyrolactone, and MA. They showed an improved cyclic efficiency of lithium/sulfur battery and made utilization of active
material, sulfur, more effective.
Microstructure and Electrical Properties of R.F. Magnetron Sputtering Derived PZT Thin Films Deposited on PbO Buffer Layer
Authors: Park Chul Ho , Son Young Gook
Published: March 2009

The MFS and MFIS structures were prepared on the Si and PbO/Si substrate by the r.f. magnetron sputtering method. When the PbO buffer layer was inserted between the PZT thin film and Si substrate, the crystallization of the PZT thin films was considerably improved, and the processing temperature was lowered. Compared with the MFS structure, memory window values of the MFIS
structure with the buffer layer were considerably improved. In particular, in the MFIS structure, the maximum value of the memory window is 2.0 V under the applied voltage of 9V for Pt/PZT (200 nm, 400ı)/PbO (80 nm)/Si structures with the PbO buffer layer deposited at the substrate temperature of 300ı.
Mechanical Alloying and Thermoelectric Properties of CoSb3 Skutterudite
Authors: Choi Moon Kwan , Ur Soon Chul , Kwon Joon Chul , Cho K.W. , Kim Il Ho , Lee Young Geun , Ryu Sung Lim
Published: March 2009

In an effort to synthesize homogenized single phase d-CoSb3, this study considers the mechanical alloying (MA) of elemental Co and Sb powders using a nominal stoichiometric composition followed by hot pressing. Single phase, undoped CoSb3 skutterudites were successfully produced by vacuum hot pressing using MA powders without subsequent annealing. Phase transformations during mechanical alloying, powder annealing, and hot pressing were systematically
investigated using XRD and SEM. Thermoelectric properties were measured and compared with the results of similar studies. Temperature dependences were also evaluated, and their correlations to phase transformation were examined.
Correlation of Thickness with the Photocatalytic Characteristic of TiO2 Thin Films
Authors: Lee Sang Wook , Jung Hyun Suk , Kim Dong Wook , Hong Kug Sun
Published: March 2009

5, 10, and 30 nm thickness of transparent TiO2 thin films were fabricated using sol-gel process, and the influence of film thickness on the photocatalytic property was investigated. The increase in film thickness was found to enhance the photocatalytic property of the films. Photocatalytic properties of each film were estimated by decomposition of stearic acid. The amount of decomposed stearic acid increased with film thickness (5 - 30 nm). For the case of 30 nm thickness film, the stearic acid was decomposed perfectly in twelve minutes. UV-vis spectra and photocurrents of each film clearly showed that the photoactivities of TiO2 films were related to the amount of absorbed UV light and band gap shift.
Application of a Ti-Ni Alloy as a Current Collector of Positive Electrode for Lithium/Sulfur Batteries
Authors: Cho Gyu Bong , Jeong Sang Sik , Park Soo Moon , Nam Tae Hyun
Published: March 2009

A 49.8 at.%Ti-50.2 at.%Ni shape memory alloy was applied to a current collector of
positive electrode for lithium/sulfur (Li/S) battery. Flexible austenitic phase having pseudoelasticity dominated in the Ti-Ni current collector at room temperature. In the discharge curve, two plateau regions due to the lithium polysulfide (Li2Sn) and the lithium sulfide (Li2S) were obviously observed. The initial discharge capacity was 1068 mAh/g for Li/S cell with the Al current collector, and that of
the cell with the Ti-Ni current collector reached 1140 mAh/g. A little bit of declined cycle performance was associated with decreased sulfur utilization owing to a reaction with dissolved Ti and Ni elements. Compared with the Al current collector used commercially, the Ti-Ni alloy with pseudoelasticity was more suitable to apply for the current collector of Li/S battery.
Electrochemical Properties of Primary Li/FeS2 Batteries
Authors: Choi Jae Won , Kim Jin Kyu , Kim Yeon Hwa , Kim Jong Uk , Ahn Jou Hyeon
Published: March 2009

Iron disulfide (FeS2) is attractive as a positive electrode material in lithium batteries because of its low material cost, environmental non-toxicity, and high specific energy density. Furthermore, natural pyrite is a secondary product of the mining extraction of coal. For such reasons, natural and synthetic pyrites have been proposed as active cathode materials in primary lithium batteries. We investigated the effect of temperature and current density on the
electrochemical properties of lithium-FeS2 batteries. The specific discharge capacity of Li/FeS2 cells varied from 700 to 900mAh/g based on FeS2.
Emissive Carbon Coating for Energy Saving
Authors: Yu Jun Suh , Sung Jae Hoon , Park Sung , Lee Jae Chun
Published: March 2009

Emissive carbon coating was prepared using a carbon black powder and a phenolic resin binder suspension. Interior of an alumina tube with an emissivity of 0.75 was coated with the emissive coating and its energy saving performance was investigated using a vacuumed alumina tube up to 1000°C. The vacuumed cavity temperature of the carbon-coated alumina tube embedded in an electrically heated furnace was always higher than that of the uncoated one for the same surface
temperature of the tube. The cavity temperature difference between the carbon-coated and uncoated tube increased with the surface temperature of the alumina tube. At the surface temperature of 1000 °C, the cavity temperature difference reached about 20°C. Heating the carbon-coated alumina to raise the cavity temperature from an ambient temperature to 1000°C at a constant heating rate of 5°C/min yielded an energy consumption of 559 Wh, while the uncoated one resulted in energy consumption of
595 Wh. As the holding time to maintain the cavity temperature of 1000°C was extended to 120 min, the energy-saving increased from 6% to 11%.
Preparation and Antibacterial Effect of Doped Tetra-Needle Like ZnO Whiskers
Authors: Zhou Zuo Wan , Liu Jing Jing , Chu Long Sheng
Published: March 2009

Tetra-needle like zinc oxide whiskers (T-ZnOw) were doped with Al3+, Fe3+ or Ag+. The morphological structures and the doped ions were characterized, and the results indicated that mostof the Aluminum existed in a second phase of ZnAl2O4, most of the Fe3+ solid-solutioned into the crystal lattice and the silver generated as nano-particles on the surface of the needles of the ZnO whiskers. Anti-bacterial experiments gave the result that Fe3+ doped T-ZnOw and the nano-silver
adnascent ZnOw had obvious effect of killing and inhibiting the bacteria such as Staphylococcus Aureus (ATCC 6538), Escherichia Coli (ATCC 25922) and Candida Albicans (ATCC 10231). The minimum inhibitory concentrations (MIC) of the related doping T-ZnOw were 55~440 PPM. Further experiments indicated that there appeared high margin of safety and no stimulation on skins or eyes for the tested animals. Products such as plastics, coatings, fibbers and papers containing 2wt% of the doped T-ZnOw had more than 99% efficiency for anti the mentioned bacteria. Effect of degradation of organic compound for the doped T-ZnOw was also evaluated by degradation of formaldehyde. The mechanism was tentatively put forward to explain the phenomena and the effect of antibiosis.
Preparation and Characterization of the Visible Light Responsive TiO2 Thin Film Photocatalysts Prepared by Magnetron Sputtering Method and Their Photocatalytic Activities for the Water Splitting Reactions
Authors: Matsuoka Masaya , Kitano Masaaki , Takeuchi Masato , Anpo Masakazu , Thomas John M.
Published: March 2009

Visible light responsive TiO2 (Vis-TiO2) thin films were successfully developed by the radio-frequency magnetron sputtering method, and their photocatalytic activities for the water splitting reactions were investigated. Pt-loaded Vis-TiO2 thin films acted as photocatalysts to decompose water involving sacrificial reagent such as methanol or silver nitrate under visible light irradiation (λ³ 420 nm). Furthermore, the separate evolution of H2 and O2 was successfully achieved under solar light irradiation by applying these photocatalysts in a H-type glass container, which consists of two water phases separated by a TiO2 thin film and proton-exchange membrane.
Influence of Spraying Power and Distance on Porosity and Microhardness of Plasma Sprayed TiO2 Coatings
Authors: Du Hao , Chen Huang , Moon Byung Kyu , Shin Jae Heyg
Published: March 2009

The influence of the two deposition parameters on microstructure, and
microhardness of plasma sprayed TiO2 coatings were investigated. It was found that a higher spraying power and a shorter distance resulted in a lower porosity and a higher microhardness for the coatings. The anisotropy on the microstructure and
microhardness of TiO2 coatings was also found. The denser microstructure is
attributed to the higher degree of melting and higher velocity of the TiO2 powders
during spraying. The improvement of microhardness is associated with the lower
porosity. The difference of porosity and microhardness between surface and cross
section resulted from their different microstructures.
Effect of LaCl3 on the Structure and Properties of Magnesium Alloys
Authors: Wu Guo Hua , Guo Hong Tao , Zeng Xiao Qin , Ding Wen Jiang
Published: March 2009

By use of the Zwick electronic universal material testing machine, X-ray diffractometer, SEM, EDX, image analyzer and corrosion test, the effects of LaCl3 on the mechanical properties, structure, fractography and corrosion behavior of magnesium alloy have been studied. The results show that minute nodular Al10La2Mn7 phases can be formed in Mg melts after fluxes containing LaCl3 are added to Mg melt. The Al10La2Mn7 phases can act as the nucleating site of γ phases, and the γ phases can be refined. With the flux containing 5% LaCl3, the σb and δ of the Mg alloy can be improved from 161MPa and 2.1% to 203MPa and 4.0% by 26% and 100%, respectively. The corrosion rate of magnesium alloys can decrease from 1.10 mg/(cm2.d) to 0.17 mg/(cm2.d) by 84% with the use of flux containing 5% LaCl3. Rare earth (RE) elements are often added to the magnesium alloy to improve the alloy structure and the room or elevated temperature mechanical properties. But up to present, the RE elements added to Mg melt is often in the form of pure RE alloy or RE master alloy [1]. Because RE is the
oxidizable material, this kind of adding process often leads to low RE utilization ratio and high use-cost. Besides, this process can easily induce segregation of RE and the appeared coarse RE phases will lower the Mg alloy mechanical properties. By far, there is few research reports about RE contained compound added to Mg alloy melt. In this paper, the effects of Lanthanum chloride (LaCl3) on the structure and mechanical properties of Mg alloy are studied for the first time. The aim is to explore a new way to improve the Mg alloy properties.
Microstructure Refinement of Magnesium Based Alloy
Authors: Xue Feng , Du Wenwen , Sun Yang Shan
Published: March 2009

Additions of grain refiners based on Ca, Ca/Si, Al3Ti and Al4C3 to pure magnesium and AZ31 alloy result in remarkable microstructure refinement. With proper amount of these refiners addition, the grain size in as-cast ingots is one order of magnitude lower than that without refiner addition. Small amount of refiner addition to alloy AZ31 increases both ultimate and yield strength significantly, and the ductility of the alloy is similar to that without refiner addition. Additions of refiner improve the deformation formability of the AZ31 alloy.The extruded and hot rolled specimens (rods or sheets) with refiner addition are crack free and exhibit higher surface quality and mechanical properties than that without refiner addition.
Orientation Dependence of Ductility of Mg Single Crystals at Elevated Temperature
Authors: Miura Hiromi , Sakai Taku , Nogawa H. , Yang Xu Yue , Watanabe Yoshimi , Miura Seiji
Published: March 2009

Orientation-controlled Mg single crystals were tensile tested at temperatures between 473 K and 673 K at a strain rate of 4.2 x 10-4 s-1 in vacuum. Though all the single crystals showed high ductility compared with that of polycrystals, the ductility of the single crystals strongly depended on the crystal orientation. The [27 -1 -26 1] single crystal showed 0.57 fracture strain, while the [3 8 -11 -1] single crystal
showed superplastic behavior of ductility over 1.8 strain. The observed strong orientation dependence of ductility seemed to be caused by orientation dependence of ease occurrence of dynamic recrystallization (DRX) in the single crystals during high-temperature deformation. The orientation dependence of ductility of Mg
single crystals will be discussed in detail concerning crystallographical orientations of the single crystals, occurrence of DRX and fracture.
Effect of Yttrium on Morphologies of Precipitation Phases along Grain Boundaries of As-Cast ZK60 Magnesium Alloy
Authors: Ma Yan Long , Zuo Ru Lin , Tang Aitao , Wang Wen Ming , Zhang Jing , Pan Fu Sheng
Published: March 2009

Morphologies of precipitation phases along grain boundaries of the as-cast Mg-6.0Zn-0.45Zr, Mg-6.0Zn-1.2Y and Mg-6.0Zn-0.6Zr-1.0Y alloys were investigated. The experimental results indicated that the main precipitation phase along grain boundary of the as-cast Mg-6.0Zn-0.45Zr was a Mg-Zn binary compound. There were two kinds of precipitation phases along grain boundaries for Mg-6.0Zn-1.2Y and Mg-6.0Zn-0.6Zr-1.0Y alloys. One grew at triangular grain boundary, which was fish-bone -like in shape and a Mg-Zn binary compound. The other distributed mainly around the grain, which was net-like in shape and a Mg-Zn-Y ternary compound. In addition, there were lots of granular phases, extending to the interior of the grain, at the rim of grain boundary phases. Y was found to affect obviously morphology of precipitation phases along grain boundary of the as-cast Mg-Zn-Zr (ZK60) alloys.
Effects of Purification Fluxes Containing Boride on AZ91 Alloy
Authors: Gao Hong Tao , Wu Guo Hua , Fan Yu , Ding Wen Jiang , Zhu Yan Ping
Published: March 2009

Purification fluxes JDMR-1 containing B2O3 and JDMR-2 containing Na2B4O7 were
developed for magnesium alloy. Density, viscosity and melting points of the two fluxes were measured. In the magnesium alloy iron concentration decreased from 0.024% to 0.004% and 0.001%, and average volume fraction of nonmetallic inclusions from 2.06% to 0.86% and 0.23% after JDMR-1 and JDMR-2 processing, respectively. Corrosion resistance and tensile properties of the magnesium alloy were greatly improved. Iron reduction mechanism was studied thermodynamically.
Effects of Heat Treatment on Microstructure and Mechanical Properties of Rolled AM50+xCa Magnesium Alloys
Authors: Peng Jianguo , Wang Qu Dong , Liu Man Ping , Chen Yongjun , Ding Wen Jiang , Suéry Michel , Blandin Jean Jacques
Published: March 2009

Effects of solution and aging treatment on microstructure and mechanical properties of rolled AM50+xCa alloys(x=0, 1, 2 wt. %) were studied. The results indicated that, with increasing solution time i, the secondary phase Mg17Al12 was dissolved into the Mg matrix and Al2Ca became thinner and shorter, then gradually broken and spheroidized.With an increase of aging time, Mg17Al12 precipitated from the Mg matrix in the form of particles and Al2Ca changed a little. After solution treatment, hardness and tensile properties of the alloy’s decreased. After the aging treatment, the alloy’s hardness increased first and decreased later while the tensile properties increased little. The solution and aging treatment can increase the ductility of AM50 and AM50+1Ca alloys. For AM50+2Ca alloy, the ductility increased after solid solution treatment and decreased after aging treatment.
Development of High Temperature Creep Resistant Magnesium Alloys for Die Casting
Authors: Liu Hai Feng , Tong Guodong , Hou Jun
Published: March 2009

A series of high temperature creep resistant magnesium alloys for die casting based on AZ91 were successfully developed by the addition of Rare Earth, and Calcium. The original target of magnesium alloy development was aimed at cylinder head cover of high power diesel engine, and tried to satisfy the temperature demands of gear-box house. The tensile property at room temperature, creep behavior at 150ı，and analysis of microstructure were discussed in this paper. The results showed that these alloys has potential for die casting to produce power-train parts, and
greatly decrease the weigh of parts.
Rapidly Solidified AZ31 Magnesium Alloy Ribbons Used in Rechargeable Batteries
Authors: Zhao Hong Liang , Guan Shaokang , Zhang Chun Xiang , Zheng Fei Yan , Wang Li Guo , Li Qing Kui
Published: March 2009

Better properties of magnesium make it a natural choice for use as an anode material in rechargeable batteries. However, the magnesium alloy thin sheets used in rechargeable batteries were produced by ingot casting and rolling. That technology was so complex and the cost was high. Rapidly solidification by melt spinning is an effect way to solve that problem. In this paper, the technology of rapidly solidified (RS) ribbons in Mg-3%Al-1%Zn-0.2%Mn alloy has been investigated using melt spinning technique. The effect of wheel speed on thickness and microhardness of the ribbons is presented. Microhardness is found to increase with the wheel speed.
Rapidly solidification leads to small grains (1~2 µm). The plasticity of the ribbons was well. The quantity of Mg17Al12 decreases with the increase in wheel speed. When the wheel speed reaches 1600 rpm, no Mg17Al12 phase precipitates. As the increase of the wheel speed, the corrosion resistance of the ribbons changes better.
Effects of Cooling Rate on Solidification Microstructure of ZK60 Magnesium Alloy
Authors: Yang Chun Mei , Zhang Ding Fei , Ding Pei Dao , Peng Jian , Chen Xu Hong
Published: March 2009

In this paper, the influence of the cooling rate on the solidified structure of ZK60 Mg
alloy has been studied by means of Gleeble-1500D thermal simulation instrument. The result showed that the grain size and grain shape depended on the cooling rate, Primary Dendrite Arm Space ( λI ) and Secondary Dendrite Arm Space ( λII) sharply decreased with the increasing of solidifying cooling rate (v) in the range of experimental cooling rate (0.2~100K/s). When superheat was constant, the empirical formulas of the relation between λI λII and v was obtained. In addition, the dependence between micro-hardness (HV) and Secondary Dendrite Arm Space ( λII) for ZK60 casting alloy was proved to be similar with Hall-Petch formula. The empirical formula for λII-HV has been proposed.
Mechanisms of Segregation Band Defect Formation in Pressure Die-Cast Magnesium Components
Authors: Cao Hai Ping , Wessen Magnus
Published: March 2009

Segregation bands which normally follow the outer contours of a casting are common in commercial magnesium alloy pressure die castings. Several models have been proposed in the literatures which attempt to explain mechanisms behind the formation of this type of segregation bands. However, it is difficult to explain some phenomena which occur in real die cast components. In this paper, a new theory concerning the formation of one common and detrimental segregation band defect (Type I) has been proposed, which is based on a coupled analysis of heat flow and volume changes during solidification. The formation of this type bands was related to a pressure drop in the liquid and resulting flow of segregated liquid from the surrounding two-phase regions. Mechanism on the formation of the other type segregation band (Type II or under surface band) is also proposed. The sudden increase of cooling rate at the moment of applying intensification pressure is believe to has main contribution to the formation of this type of bands.
Microstructure and Mechanical Properties of Extruded Mg-Zn-Nd-Y-Zr-Ca Alloy
Authors: Li Qiang , Wang Qu Dong , Zeng Xiao Qin , Ding Wen Jiang , Tang Quanbo , Huang Shao Dong
Published: March 2009

Nd, Y and Ca containing Mg-Zn-Zr alloys are produced by electromagnetic direct-chilling casting process, and extruded at a temperature of 643K with two extrusion ratios of 38:1 and 22:1, respectively. The grain size is markedly reduced from 80µm in as-cast alloy to 2~5µm in as-extruded alloy due to dynamic recrystallization, and lamellar eutectics at grain boundaries in as-cast alloy are broken up and fine precipitates in the matrix come forth during hot extrusions. Mechanical properties
of the alloys are measured by tensile test from room temperature to 523K. Nd, Y and Ca are favorable to the strength of the hot-extruded alloy, especially the elevated-temperature strength, which is above 200MPa in ultimate tensile strength at 523K.
Recent Technological Advancement and Developmental Trend of Pidgeon Process in Smelting Magnesium in China
Authors: Wang Xin , Zang Jingchun , He Junhao
Published: March 2009

The crude magnesium is produced mainly by Pidgeon Process in China. Although
Pidgeon Process has achieved certain technological advance in the past ten years, it is mainly by sacrificing energy, environment, and cheap labor. In the 21st century, human activities should be energy-saving and environment friendly. The equipment used in the Pidgeon process should be improved as early as possible by elevating its automatic level in order to save energy, protect the environment and realize scale economy of magnesium production. This will be the developmental trend of Pidgeon process in smelting magnesium.
Evaluation of Magnesium Extrusion Production
Authors: Zhou Ming , Cao Jianyong , Yu Fulin , Wei Xia
Published: March 2009

Compared with any other pressure processing methods, extrusion is more prone to
develop the plasticity of the metal. Extrusions have much better size precision and surface quality than products by rolling and forging. As one-shot molding process, extrusion can eliminate some machining. In addition, extrusions have very high strengths and elongations because of their compact interior structures and fine grains. This paper summarizes some experiences and plans in extrusion production of CQMST(Chongqing Magnesium Science & Technology Co.Ltd). Magnesium, a plentiful element with density of 1.78g/cm3，2/3 of aluminum and 1/4 of steel, is
characterized by its high specific strength and toughness, good dumping performance, thermal conductivity and electromagnetism shielding as well as recyclability. Following the advancing technologies of magnesium smelting, high pressure processing, surface treatment and soldering since 1990’s, the prices of magnesium and its ingot stepped down. As an important light engineering material, magnesium application is growing at annual speed of 15%, much higher than aluminum, copper, zinc, nickel and steel. In China, magnesium and magnesium alloy development, application and industrialization has been placed on the National “Tenth Five-year Plans” and the National “863” Scheme, which indicated the coming of new age for magnesium and magnesium alloy development and application in China. In the past, most of the magnesium products were produced by casting, especially die casting and thixomolding. It’s always considered that the crystal structure of magnesium is hexagonal close-packed, and only two slip planes exist at room temperature, so compared with other alloys, it’s very difficult to produce magnesium parts by forging, rolling or extrusion. Nevertheless, practice showed that if heated to a certain temperature, magnesium extrusion may not be hard work, and even easier than 5056 and 2024 aluminum. When extruded with distributary die, magnesium alloy can have better soldering performance than aluminum alloys mentioned above, just because new slip system forms along with increasing temperature (>225°C) and accordingly increases the
plasticity of magnesium.
Large Profile Magnesium Alloys Extrusions for Automotive Applications
Authors: Rosen G.I. , Segal G. , Lubinsky A.
Published: March 2009

The aim of this project is to develop magnesium alloys extrusion technology for large
profiles for application in the automotive industry. In particular it is expected to significantly reduce chassis weight, thus leading to fuel consumption reduction and enhancement of performance of the cars produced by the end user. The entire process required for magnesium alloys extrusion of automobile chassis will be addressed as a first attempt of large magnesium profile extrusion. The challenge of large magnesium profile extrusion (outer diameter up to 10") has never been addressed due to technological barriers that relate to limited capability of magnesium extrusion technology. However, these barriers can be overcome if one has control over the starting material. Since the final performance of the finished product depends on the original microstructure formed over Direct Chill (DC) casting, homogenization, extrusion and subsequent heat treatment, no processing step can be isolated from the other. The R&D activities will focus on alloy selection, production of large magnesium billets, die design, heat treatment and extrusion parameters. These will be accompanied by an economic assessment of the new technology and additional applications.
The Effects of Grain Size on Ductility of AZ31 Magnesium Alloy
Authors: Wang X.L. , Yu Yong Ning , Wang Erde
Published: March 2009

It is well known that the ductility of magnesium and magnesium alloy is too poor to be
processed. After normal hot extrusion, the ductility of magnesium alloy will be improved, but not noticeably. In this paper, further extrusion (Extrusion Ratio is 6.25) is adopted to commercial AZ31 magnesium alloy rods (Extrusion Ratio is 2) at different temperatures in order to refine the size of grain, then the rods with the crystallite size between 4-10μm is obtained, and the influence of crystallite with different grain size on the ductility of this alloy is investigated further. A lot of experiments and research indicate that: the elongation of the initial billet with the grain size of 30μ m can reach about 12%; after extrusion at different temperatures, the grain size can be refined to below 10μm, and the ductility goes up to 24%-30%. It also shows that, when the grain size of AZ31 magnesium alloy is below 10μm, the ductility is effected obviously. Only when the grain size is about a few microns, the ductility of AZ31 magnesium alloy will be improved noticeably.
Preparation of Anhydrous Magnesium Chloride from Bischofite (MgCl2·6H2O) I. Reaction Crystallization of Magnesium Chloride Hexammoniate
Authors: Wang Xiang Tian , Zhao Jian Hai , Song Xing Fu , Wang Jin , Yu Jian Guo
Published: March 2009

Magnesium chloride hexammoniate (MgCl2·6NH3) is an intermediate product for
preparation anhydrous magnesium chloride by reaction crystallization method. An experiment study of a semi-batch reaction crystallization is presented. In a single feed operation, magnesium chloride solution is fed to a stirred methanol solution mixed with ammonia to crystallize magnesium chloride hexammoniate. The median crystal size of product increases with increasing stirring rate, reaches a maximum, and then decreases again. Decreasing feed rate or decreasing stirring time increases the crystal size significantly. The reaction temperature and concentration of magnesium ion can also influence the crystal size distribution (CSD). A double feed operation can create larger crystal size than that of single feed operation. The relationship between crystal size and the content of water of the product is discussed.
Press Forming Technology Using Superplastic Deformation for Mg Alloy Sheet
Authors: Fujii Hiroyuki , Iwasaki Hajime , Araki Jacky Kazuo
Published: March 2009

The square-cylindrical cup of AZ31 Mg alloy with a depth of 50mm and a width of 50 mm was successfully deep drawn from a rolled sheet with a thickness of 0.5 mm using a hydraulic press machine with a capacity of 60 tons. The blank was heated between the die and the blank holder kept in a temperature of 300 oC .The forming time was about 3 seconds. The fine-grained microstructure was observed at the corner with a sever strain. The grain refinement caused by the dynamic recrystallization contributed to generate high strain-rate superplasticity.
Effect of Microstructures and Texture Development on Tensile Properties of Wrought Magnesium Alloys Processed by ECAE
Authors: Huang Zan Wen , Yoshida Yu , Kamado Shigeharu , Kojima Yo
Published: March 2009

4-pass ECAE processing was applied to two kinds of magnesium alloys, AZ31 and
ZK31. Subsequently, hot rolling was carried out as a secondary forming process. After ECAE processing, the samples have fine and equiaxed grains. The basal plane of AZ31 alloy is inclined at about 450 to the extrusion direction, while that of ZK31 alloy is parallel to the extrusion direction. As a result, tensile strength and 0.2% proof stress of ZK31 alloy are higher than those of AZ31 alloy. On the other hand, the basal plane orients parallel to the rolled surface in the Subsequently rolled samples and, therefore, tensile strength and 0.2% proof stress are improved significantly.
Furthermore, the AZ31 alloy has higher ductility than ZK31 alloy.
Microstructure and Mechanical Properties of AM50+xTi Magnesium Alloys Extruded from As-Cast and Solution Treated Conditions
Authors: Wang Qu Dong , Chen Yongjun , Peng Jianguo , Liu Man Ping , Ding Wen Jiang , Suéry Michel , Blandin Jean Jacques
Published: March 2009

Microstructure and mechanical properties of AM50+xTi (x=0,0.01,0.1wt%) magnesium alloys extruded from as-cast and solution treated conditions have been studied. Results show that Ti element obviously refines the microstructure of AM50 magnesium alloy and Mg17Al12 phase. Only 0.01 wt% Ti addition can make the Mg17Al12 phase turn into particles and small rod-like shape. Ti addition improves tensile strength at room temperature, and obviously improves elongation at elevated temperatures up to 200°C. The AM50+xTi alloys extruded from as-cast have better tensile strength at room temperature and better elongation at 100°C, 150°C and 200°C than that of AM50+xTi alloys extruded from solution treatment; The plasticity of AM50 magnesium alloys increases with Ti content increasing and temperature increasing for the tensile fractograph.
Effects of Triethanolamine on the Performances of the Anodicing Film of AZ31B Magnesium Alloy
Authors: Ding Yurong , Guo Xing Wu , Jiang Yong Feng , Zeng Xiao Qin , Ding Wen Jiang , Zhu Yan Ping
Published: March 2009

Formation behavior and performances of anodic film grown on AZ31B alloys were
systematically studied in Na2SiO3 system electrolyte with varying triethanolamine (TEA) content. The growth behavior and appearance of anodic film were significantly affected by the TEA content. The film growth speed increased because of the addition of TEA. Whitish gray lubricous barrier-type film were obtained in the electrolyte with TEA. The film density was obviously increased by the addition of TEA. Moreover, the film produced in electrolyte with TEA possessed a high degree of
corrosion resistance and obviously better than that formed in electrolyte without TEA. EDX analysis indicates that, as the concentration of TEA increased, the contribution of the elements from the base alloy increased.
Effects of Ni Electroless Plating on Electrochemical Properties of Mg2 Ni Hydrogen Storage Alloys
Authors: Tang Yougen , Xu Yijun , Lu Zhuguang , Huang Bo Yun
Published: March 2009

Effects of nickel coating on electrochemical properties of Mg2Ni hydrogen storage alloys were presented in this paper. X-ray diffraction ( XRD) and scanning electron microscope (SEM) were employed to examine the crystal structure and surface morphologies of the as-obtained bare and Ni-coated Mg2Ni alloys and their electrochemical properties were characterized by cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS). Results showed that Ni coating not only decreased charge transfer resistance, but also decreased H atom diffusion resistance for Mg2Ni alloys. It was also found that Ni coating effectively improved the discharge capacity.
The Corrosion Behaviour of Mg Alloy AZ91D/TiCp Metal Matrix Composite
Authors: Jia Suqiu , Jia Shu Sheng , Sun Guangping , Yao Jun
Published: March 2009

The corrosion of a magnesium-based MMC, comprising a AZ91D alloy matrix and 5
vol% titanium carbide particles has been studied in saline environments, using immersion and electrochemical tests. Corrosion was localized initially and developed subsequently into general corrosion , the local corrosion rate of AZ91D/TiCp being faster than diecast AZ91D due to the formation of less protective corrosion products. Galvanic corrosion for AZ91D/TiCp, due to coupling of the matrix and reinforcement, was more severe than diecast AZ91D.
Low-Cycle Fatigue Behavior of Magnesium Alloy AZ91
Authors: Chen Li Jia , Shen Jian , Wu Wei , Li Feng , Wang Yue , Liu Zhen
Published: March 2009

Fully-reversed total-strain-amplitude-controlled fatigue tests were performed in
laboratory air at room temperature for the magnesium alloy AZ91. Experimental results showed that during the experiment significant cyclic strain hardening occurred throughout the imposed strain amplitudes. It was found that the relationship between plastic strain amplitude, elastic strain amplitude and reversals to failure can be well described by Basquin and Coffin-Manson equations. In addition, the strain fatigue parameters of the AZ91 alloy were determined through analyzing the corresponding strain fatigue life data.
Effect of Inoculation on the Damping Properties of Mg-8Zn-4Al-0.3Mn Alloy
Authors: Guan Shaokang , Wang Jian Qiang , Chen Jing Yang , Zhao Hong Liang , Li Qing Kui
Published: March 2009

The effects of inoculation on the damping property of Mg-8Zn-4Al-0.3Mn alloys have
been investigated. The results show that the damping property of ZA84 alloys reduces at room temperature after the addition of RE, whereas the damping property at high temperature increases obviously. The damping property of ZA84 alloys at room temperature and high temperature improves respectively after the addition of Al5TiB. It has reached Q-1=0.01 at room temperature with 0.25% Al5TiB. There exists a damping peak in all alloys at high temperature because of the viscous sliding of the grain boundaries and the inteneration of φ (Al2Mg5Zn2) phase at high temperature. It was found that the addition of RE could delay the temperature of damping peak occurs. The main damping mechanisms of ZA84 magnesium alloys with RE and Al5TiB additions are the dislocation damping and interface damping. The higher the movable dislocation density is, the finer the grains are and the more the grain boundaries and phase interfaces are, the better damping property of ZA84 alloys is.
Effect of Deformation on the Damping Capacity of Magnesium Alloys
Authors: Hu Xiao Shi , Wu Kun , Zheng Ming Yi , Xu Shi Wei , Zhang Y.K.
Published: March 2009

Equal channel angular extrusion (ECAE) was applied to an as-cast AZ91D magnesium alloy. The strain amplitude dependence and temperature dependence of damping capacities of the as-cast and ECAE processed AZ91D alloys were investigated by dynamic mechanical analyzer (DMA). Microstructures of AZ91D alloys after ECAE were observed by optical microscopy (OM). In higher strain region, the damping value of 4-pass ECAE deformed AZ91D alloy was the highest
among all the AZ91D alloys under different conditions. The damping peaks of ECAE deformed AZ91D alloys detected during heating from room temperature to 400°C were considered to be related to the migration of grain boundaries and the movement of dislocations during recrystallization.
High Active Hydrogen Storage Alloy Mg2NiH4 and Mg2Ni Synthesized at Temperatures Lower than 733 K
Authors: Liu Xiao Feng , Li Li Quan
Published: March 2009

Hydrogen storage alloys Mg2Ni and Mg2NiH4 were synthesized at below 733 K by the process HCS. The product was examined by X-Ray diffraction and hydriding / dehydriding dynamics was tested. The result reveals that (1) High pure products of Mg2Ni and Mg2NiH4 can be obtained even at temperature 673 K and 0.1 MPa argon and 1.0 MPa hydrogen, respectively; (2) Both products are high active absorbing hydrogen > 3.2 mass % at 603 K without activation process. The result is
very attractive due to the low temperature and pressure for the production of hydrogen storage alloys.
Non-Destructive Analysis of Surface Stresses Using Grazing Incident X-Ray Diffraction
Authors: Braham Chedly , Baczmanski Andrzej , Seiler Wilfrid , Shiraki N.
Published: March 2009

The X-ray diffraction measurements based on the grazing incident geometry were applied to determine lattice strains in polycrystalline materials. This method enables a non-destructive measurement at chosen depth below the sample surface. The volume, for which the stress is measured, is well defined and it does not vary during experiment. The multireflection method was used for analysis of the experimental results since the interplanar spacings were measured for various orientation of the scattering vector as well as for various crystallographic planes {hkl}. Applying two different wavelengths of X- ray radiation and various incident angles non-destructive measurements of the residual stresses in function of penetration depth were performed. The variation of stresses in plastically deformed surface layers of steel samples was successfully determined and the values of the stresses were confirmed by standard diffraction measurement.
Residual Stress Error Introduced by Truncated Patterns: Prediction and Correction
Authors: Ferreira C. , François Manuel , Guillén Ronald
Published: March 2009

The truncation of diffraction patterns in residual stress determination is often observed for broadened peaks when the 2θ acquisition range is not wide enough. The loss of information effects induced can either be traduced by a bad estimation of the background line, for the methods including a background subtraction, or a restriction of the analysis area for the others. In that borderline case, the results obtained by all methods with theirs specific parameters, developed to estimate the peak localisation are rather distributed in a wide range of stress values. In this paper we propose to review and to test some of the most common methods for stress evaluation (parabola, middle of chord, centred centroïd, asymmetrical pseudo-Voigt fitting). A separate study is made concerning error introduced on the 2θ peak position and on the final stress value estimated. For the parabola method, an analytical expression including some approximations such as the peak shape and its full width at half maximum is then given for the prediction and the correction of these errors. This study is sponsored by PSA PEUGEOT-CITROËN, RENAULT and SNECMA.
Effects of Temperature Fluctuations on X-Ray Stress Determination
Authors: François Manuel , Ferreira C. , Guillén Ronald
Published: March 2009

The results presented in this paper are part of a process to analyse systematically the sources of uncertainty in X-ray stress determination. They concern one part of the effects of temperature variations which could intervene either as random fluctuations or as a monotonic drift during the acquisition. The proposed formulation is in agreement with the recommendations of the ISO guide on the expression of uncertainty (GUM). It was found that the effect is usually negligible for laboratory experiments which are often temperature controlled and for most materials. However
the uncertainty can reach 20 MPa for austenitic steels and a temperature drift of 2 K.
Principle and Method of X-Ray Computer Tomography on Residual Stress Measurement
Authors: Chen Yu-an , Zhou Shang-qi , Ren Qin
Published: March 2009

X-ray computer tomography for non-destructively measuring residual stress with depth resolution was suggested to aim at improving of traditional X-ray stress analysis in this paper. Based on higher penetrating capacity of X-ray in low atomic order materials it could non-destructively measure three-dimensional residual stresses and calculate the stress free lattice spacing, d0, by current X-ray stress analyzer with taper slits. The evaluation of reliable results were controlled by three criteria, linear correlation coefficient, R, Poisson’ ratio, ν, and the stress free
lattice spacing, d0. Finally, the residual stresses in the axial direction around the weld of arc Beryllium weldment could be calculated by this method.
A New Method for Measuring Residual Stress Relaxation during Nanoindentation
Authors: Wang Fei , Xu Ke Wei
Published: March 2009

The work of nanoindentation approach is developed and applied for measure of
residual stress relaxation during indenter penetrates in thin films. The residual stress at given penetration depth is measured from the different integral area which under load-depth curve of different stress state. This method can measure residual stress relaxation without the need for estimating yield strength, strain hardening index and hardness.
Suppression of Surface Effect by Using Bent-Perfect-Crystal Monochromator in Residual Strain Scanning
Authors: Vrána Miroslav , Mikula Pavol
Published: March 2009

Using our long experience in Bragg diffraction optics we successfully used focusing
principles for substantial increasing both luminosity and resolution of the strain scanners with respect to the conventional devices. Monochromatic neutrons are selected by the cylindrically bent monochromator from the reactor spectrum. There is a strong correlation between divergences of incoming and outgoing beams with respect to the polycrystalline sample, which can be easily manipulated by changing the monochromator bending radius. By setting a proper value of the radius, a narrow, quasiparallel and highly luminous output beam can by adjusted. The strong
correlation between wavelength and direction of incoming and outgoing beams depending on the monochromator bending radius can be as well used for suppression of surface effect in residual strain scanning. In scanning near a sample surface aberration peak shifts arise due to the fact that the gauge volume defined by input and output slits is partially out of the sample and its value can be of the same order as the residual strain effects. In this work we demonstrate that by changing of the bending radius of monochromator, this surface effect can be suppressed to values smaller then experimental errors in residual strain scanning.
Neutron Determination of Residual Stress in a Nitrided Notched Part
Authors: Fabre Agnès , Barrallier Laurent
Published: March 2009

Nitriding is an hardening thermomechanical treatment generally used to improve fatigue life of steel parts, like gear for example. Another effect of this treatment is generating superficial stress, influenced by nitriding conditions, composition of steel and geometry of the part. This work deals with the effect of shape on the residual stress profile obtain after nitriding on a gear tooth. The residual stress profile was determined using neutrons diffraction technique.
The Vibratory Stress Relief of Drill Pipe
Authors: Zhang Y.B. , Chen S.W. , Liu C.J. , Sun Y.H. , Sun M.C. , Wang R.K.
Published: March 2009

Drill pipe is made from 35CrMnMo. The used drill pipes were curved, when they were
aligned and deformed, there is high macro residual stress in the aligned used drill pipe. In active service, the macro residual stress releases and thus causes considerable deformation of the aligned used drill pipe. The vibratory stress relief is introduced to the aligned used drill pipe. The vibratory stress relief of the aligned used drill pipe was carried out. The mechanical properties of the aligned used drill pipe were measured before and after vibration. Seven points vibratory stresses were measured. The macro residual stress was measured before and after vibration. The macro residual stress decreased notably. The mechanical properties changed slightly. The vibratory wave is standing wave. The vibratory stress relief is valid for macro residual stress relieving of the aligned used drill pipe. The aligned used drill pipes were steady in latter active service. The mechanism of the macro
residual stress relieving by vibration on the aligned used drill pipe is discussed. The
“double-dynamic mechanism” is introduced to explain the course of macro residual stress relieving in the test.
The Effect of Fatigue on Residual Peening Stresses in Aerospace Components
Authors: King Andrew , Evans A.D. , Withers Philip J. , Woodward C.
Published: March 2009

The Rolls-Royce Wide Chord Fan Blade (WCFB) is an innovative aerospace
component, manufactured from Ti-6Al-4V alloy. The blade roots experience fatigue loading during flight, and are subject to fretting fatigue where they contact the fan disc. Shot peening (SP) and laser shock peening (LSP) are mechanical surface treatments which have been applied to the blade root to improve fatigue strength and damage tolerance. Both techniques cause local plastic deformation of the material, resulting in a layer of compressive residual stress. The compressive
stress from LSP may reach a depth of 2mm in titanium, compared with only 0.25mm for conventional SP. These compressive stresses are balanced by subsurface tensile stress. LSP is reported to cause less work hardening than shot peening.
It is important to understand the stability of the residual stresses during service conditions so that accurate fatigue life assessments can be made. Fatigue testing has been carried out on blade root section test pieces and on notched three point bend samples. Residual strain and stress measurements have been made on both types of sample. Residual strain measurements have been made using monochromatic and pulsed time-of-flight neutron diffraction techniques. The large penetration lengths of these types of radiation allow accurate residual strain measurements to be made non-destructively, deep inside a component. Because no material removal is required, no stress relaxation occurs, allowing the measurement of balancing tensile stresses. LSP and SP samples have been studied, both in the as-received condition and after fatigue.