bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Stress Distribution Near Crack Tip in Beryllium Compact Tension Specimen
Authors: Dong Ping , Li Rui Wen , Li Sheng He
Published: June 2010

In order to evaluate the fracture characteristic near the crack tip of beryllium specimen, beryllium compact tension specimen with plane strain state is designed. The stress distribution near the crack tip is measured at different loading level by X3000 stress analyzer. Moreover, a finite element model for calculated the stress and strain fields in beryllium compact tension specimen has also been set up. As a result, the stress and strain distribution near the crack tip at different loading has been calculated by this model. According to the critical tension loading of beryllium specimen, the maximum plastic strain and the radius of the plastic zone near the crack tip are determined, where the maximum plastic strain near the crack tip is about 0.018 and the maximum radius of plastic zone is about 0.3mm. Altogether, the fracture toughness of beryllium is obtained, which is about 19.1MPam1/2.
Evaluation of Fretting Wear Behavior on the Simulated Supporting Structures of a Dual-Cooled Nuclear Fuel Rod
Authors: Lee Young Ho , Kim Hyung Kyu
Published: June 2010

A dual-cooled fuel (i.e. annular fuel) has been proposed to substantially increase in power density and safety margins compared to a solid fuel in operating PWR plants. As this fuel rod has larger outer diameter than the conventional solid rod to accommodate sufficient internal flow, new supporting structure geometries should be designed and their reliabilities (i.e. vibration characteristics, fretting wear resistance, etc.) are also examined with both analytical and experimental methods. In this study, the supporting structure characteristics and fretting wear behaviors are analyzed and examined by using two kinds of simulated supporting structures that have embossing and cylindrical shapes. Their supporting structure characteristics were examined by using a specially designed test rig and their results were compared with that of analytical method. Also, fretting wear behaviors of simulated supporting structures were experimentally examined with considering the effect of contact shapes and their stiffness values. Based on the test results, the relationship between the supporting structure characteristics and their fretting wear behaviors was discussed in detail.
Quantification of the Interface Interactions in Polymer Nanocomposites
Authors: Zeng Qing Hua , Xu Wen , Yu Ai Bing , Paul Donald R.
Published: June 2010

Interfaces are important for many properties and applications of multiphase materials. This is particular true for particle-reinforced polymer composites, where the interfacial characteristics between particle and polymer play a crucial role in load transfer and mechanical properties. In polymer nanocomposites, the adhesion strength between particle and polymer matrix is a major factor in determining their mechanical properties. In this work, we present our recent study towards the quantification of the interaction strength at the interface of clay-based polymer nanocomposites by molecular dynamics simulation.
Extended-Chain Crystals of High-Pressure Crystallized Poly (Ethylene Terephthalate) Oligomer/Bisphenol-A Polycarbonate Blends
Authors: Lu Jun , Xi Dai Kun , Huang Rui
Published: June 2010

In this study, the crystallization behaviors of the poly (ethylene terephthalate) oligomer/bisphenol-A polycarbonate (PETO/BAPC) blends were investigated under high pressure, and the recovered PETO/BAPC samples were characterized using XRD, DSC, SEM and AFM. The results showed that high-quality extended-chain single crystals with large c-axis thickness were formed in the multi-phase system within a relative short time, and the inner defects of the disclosed crystals could be removed by a self-healing process through high-temperature and high-pressure annealing. Morphologies of extended-chain crystals with different characteristics were also revealed with SEM and AFM. Wedge-shaped and bent extended-chain morphologies suggested that sliding diffusion and transesterification occurred simultaneously in the system, and the crystallization of the large crystals was a self-assembling process induced by chemical reactions at high pressure. This process provides a new route to grow large polymer extended-chain crystals and suggests self-assembly under high pressure is a promising method to create materials with new structures and properties.
A Study on Structual Strength in Body Structure of Composite Material
Authors: Yoon Sung Cheol , Ryu Joon Hyung , Kim Jeong Guk
Published: June 2010

This study introduces the structural analysis and the testing results of the composite structure which is applied to tilting train in Korea. The composite structure is made of aluminum honeycomb structure materials like a sandwich. The static load test was performed to evaluate the structural characteristic and stability of the composite structure. Considering the vertical, compressive, torsional load and 3-point supporting type as a testing terms, the structural stability of a carbody was evaluated. Load test are based on "Performance Test Standard for Electrical Multiple Unit" with the reference code JIS E 7105. The test results have been very safety and stable for design load conditions.
Effect of Interfacial Reaction on High Temperature Properties of Fe-Cr-Si Fiber Reinforced AC8A Aluminum Composites
Authors: Fuyama Nobuyuki , Terayama Akira , Fujii Toshio , Shiraishi Tohru , Miyake Yuki , Sasaki Gen
Published: June 2010

Metallic fibers (Fe-Cr-Si) with an excellent high temperature strength are expected to be use as a reinforced material of the engine piston head. However, the high reactivity of Al with most metals has disturbed the use of metallic fibers in aluminum composites until now. In this study, the influence of the reaction products at the fiber/matrix interface on high temperature properties of the composites was investigated by different solution treatment conditions. It is found that hardness and strength increase with an increase the solution treatment temperature (Tst). Reaction products (Al-Fe intermetallic compounds) resulting from solution treatments were formed along the fiber/matrix interface at 773 K or higher. The composites without interfacial reaction products (Tst=763 K) showed excellent rotating-bending fatigue life at 573 K. The fatigue crack propagation in this composite occurred at the necking region of the metal fiber because no cracks were observed in the interfacial reaction products.
Cast Bonding of Cast Irons to Ferritic Stainless Steel
Authors: Cingi Celal , Rauta Veijo , Niini Eero , Orkas Juhani
Published: June 2010

Composite metal products consisting of two different alloys can be prepared by a few methods. Cast bonding is one of these methods. The bond between the two materials forms primarily in the solid state by diffusion, after casting of a cladding alloy on to the preheated surface of a substrate. In this work, a ferritic stainless steel was used as the substrate, and, gray iron or nodular iron as the cast alloy. It was found that these two alloys can be successfully joined, and under specific casting parameters, a very strong bond develops between the two alloys. Bond strength was found to be greater than that of gray iron. Microstructural zones on both sides of the bond were studied. It was found that diffusion of chromium into iron and diffusion of carbon into steel is significant in bonding. Chemical composition changes due to diffusion was studied by EDS. Fe-Cr-Mn carbides were formed at the bond during the casting. These carbides were largely eliminated by a subsequent high temperature heat treatment.
Crystallization of Amorphous SiCN Matrix of C/SiCN Composite under Conditions of Vacuum and Tension-Tension Fatigue
Authors: Xia Yi , Qiao Sheng Ru , Yan Chao , Zhang Cheng Yu
Published: June 2010

Carbon fiber reinforced SiCN matrix composite (C/SiCN) was used in present investigation, its amorphous SiCN matrix was derived from the hexamethyldisilazane by chemical-liquid and vapor-infiltration into the carbon fiber weaving preform. The tension-tension fatigue was conducted at 1300°C in vaccum both for the as-received and 1500°C-annealed C/SiCN with 60Hz and 41MPa. The microstructure evolution of SiCN during fatigue was examined by X-Ray diffraction and transmission electron microscopy (TEM). The results indicate that pronounced crystallization takes place in the as-received C/SiCN during fatigue, and only β-SiC crystallites are detected within amorphous SiCN matrix, Si3N4 can’t be detected. This is different from the literature that reports that there isn’t any crystallization when C/SiCN is annealed at 1300°C under nitrogen or argon atmosphere. As for 1500°C-annealed C/SiCN, there isn’t any crystallization during fatigue, and it can be attributed to the phase stabilization in the SiCN matrix after annealing. Both vacuum and fatigue stress promote the crystallization course because they accelerate the decomposition of amorphous SiCN and atomic diffusion. Degradation – crystallization mechanism is used to explain the crystallization behavior of amorphous SiCN under condition of vacuum and tension-tension fatigue.
A Method to Extract Materials Properties from Multilayer Material Systems
Authors: Moy Charles , Bocciarelli Massimiliano , Ringer Simon P. , Ranzi Gianluca
Published: June 2010

This article presents an inverse analysis method based on an instrumented indention to extract materials properties from multilayer material systems. In this case, a 12-layers system comprising of two alternate materials is considered. Each layer is 1 μm thick. The material properties selected for the layers are within the range of common commercial aluminium alloys. The yield stress and strain hardening exponent of the two layers were identified based on a power law type equation to define the stress-strain relationship. A 2D axis-symmetric indenter having 70.3 half angle was used, which is representative of a Berkovich or a Vickers indenter. The use of finite element analyses was substituted with a fast and equally accurate approach for the iterative optimization procedure. Thus, the computation time was considerably reduced. The robustness is tested using pseudo-experimental results, in terms of indentation curve and imprint on the material, with added random noises of 2.5%, 5.0%, 7.5% and 10.0%. The proposed approach provides a good estimate of the sought material properties. It is envisaged that this approach can become of assistance in the evaluation of the material properties for multilayer coatings and small devices.
Thermoelectric Performance of Half-Heusler TiNiSn Alloys Fabricated by Solid-Liquid Reaction Sintering
Authors: Kimura Yoshisato , Asami Chihiro , Chai Yaw Wang , Mishima Yoshinao
Published: June 2010

A new fabrication process was proposed for half-Heusler type TiNiSn thermoelectric alloys. Based on the result that the TiNiSn phase can be formed easily at the Sn(Liquid)/TiNi(Solid) interface, the liquid-solid reaction-sintering process was developed using TiNi and Sn powders. The TiNi compound powders were prepared by the atomization method using argon gas atmosphere. We have fabrictaed nearly single-phase TiNiSn alloys and evaluated their thermoelectrical properties; the presnt TiNiSn alloys have large electrical power factor of about 3.5 mWm-1K-2, and the maximum value of dimensionless figure of merit, ZT = 0.67, can be achieved at around 700 K even without tuning of the carrier concentration through alloying elements.
Hydrogen Permeation Properties of Pd-Coated Ni37.5Nb27.5Zr25Co5Ta5 Amorphous Membrane
Authors: Chin Hong Seok , Kim Yu Chan , Kim Yoon Bae , Suh Jin Yoo , Lee Woo Young , Hong Tae Whan , Fleury Eric
Published: June 2010

The hydrogen permeation properties of the Pd-coated Ni37.5Nb27.5Zr25Co5Ta5 amorphous membranes have been investigated at 673 and 723K for 720 hours (1 month). Values of the hydrogen permeability during these long term tests were found to be reduced of about 50 and 30 % at 673 and 723K, respectively. The reduction in the hydrogen permeability could be correlated to the change in the composition of the coating as well as at the interface between Pd coating and Ni-based amorphous membrane.
Effect of Annealing on the Hydrogen Permeation and Mechanical Behaviour of Nb-Ni-Zr Alloy Membranes
Authors: Wong Timothy , Yu Z. , Suzuki K. , Gibson M.A. , Ishikawa K. , Aoki K.
Published: June 2010

Nb/NiZr composite alloy membranes have been reported to have hydrogen permeabilities higher than that of pure Pd. Since the hydrogen permeation behaviour in these composite alloys is highly microstructure sensitive, hydrogen permeability is likely to depend on annealing conditions. This work has looked into the effect of annealing on the hydrogen permeability of as-cast Nb-Ni-Zr alloys with the goal of helping in the advancement of Nb-based alloy membranes as cost-effective alternatives to the Pd-based alloy membranes used for hydrogen purification. Nb-Ni-Zr alloy ingots of different compositions were prepared by argon arc-melting. The samples were vacuum sealed in quartz tubes and annealed isochronally for 1h between 500°C and 900°C. It was found that the samples annealed at 900°C exhibit higher hydrogen permeability than the as-cast samples. However, these samples were found to be less resistant to hydrogen embrittlement and the membrane exhibited cracks after the permeation test. The main mechanical failure mechanism was due to intragranular cracking for the alloys with high Nb content whilst the mechanism was observed to be intergranular cracking for alloys with lower Nb-content. The mode of failure did not change after annealing.
Effect of Dissolved Hydrogen on the SCC Susceptibility of SUS316L Stainless Steel
Authors: Nakagawa Katsuhito , Nono Masahiro , Kimura Akihiko
Published: June 2010

The SSRT behavior in hydrogen dissolved hot water was investigated for cold worked SUS316L at a strain rate of 5 x 10-7/sec. The cold work to 75% thickness reduction of the as-annealed steel resulted in the hardness increase from 150 HV to 420 HV. The tensile yield stress of the cold worked specimens (CW=75%) was about 1000 MPa and the total tensile elongation was significantly reduced from 0.8% of annealed specimen to 0.14% of the 75%CW specimen. The results of EPR tests on SUS316L steel indicated that the EPR-DOS increased with increasing sensitization period at 700°C and decreased with increasing degree of cold work or reduction in thickness. In the water with hydrogen dissolution of 0.4 ppm, many IGSCC type cracks were nucleated on the specimen side surfaces, while the fractured surface was almost TGSCC. No such a SCC as observed in hydrogen dissolved water was observed after the test in oxygen dissolved water. The susceptibility to SCC increased with increasing hydrogen content in hot water. Cold work caused the reduction of the number of surface cracks and disappearance of IGSCC.
Synthesis of Ni-Al Intermetallic Nanoparticle Catalysts by Vacuum Arc Plasma Evaporation
Authors: Xu Ya , Yang Jun You , Demura Masahiko , Hara Toru , Hirano Toshiyuki
Published: June 2010

In order to pursue high catalytic performance of Ni-Al intermetallic compounds for hydrogen production, we synthesized Ni-Al intermetallic nanoparticles from Ni-Al alloy ingots by vacuum arc plasma evaporation technique for the first time. The characterization of the synthesized nanoparticles was carried out using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy. The catalytic properties of the Ni-Al nanoparticles for methanol decomposition were evaluated. It is found that the nanoparticles had a large surface area above 70 m2/g, and showed very high catalytic activity for methanol decomposition.
Research and Development of Nano-Composite Materials for Hydrogen Storage
Authors: Kojima Yoshitsugu
Published: June 2010

Hydrides with light elements such as MgH2, LiH, NH3 and NH3BH3 are known as high hydrogen containing materials. However, the high work temperature and the slow reaction rate limit the practical application of hydride systems. Those properties can be improved by the nano-composite materials. The nano-composite materials for hydrogen storage encompass a catalyst and composite hydrides at the nanometer scale. The catalyst increases reaction rate. The thermodynamic stability of the nano-composite materials can be controlled by the composite hydrides. In addition, the hydrogen absorption kinetics is accelerated by the nano-size materials and they may change the thermodynamic stability of the materials. In this study, we reviewed our experimental results on hydrogen storage properties of light weight nano-composite materials. The Mg-based nano-composite material with Nb2O5 showed excellent kinetics as compared with that of Mg. The Li-Mg-N-H system absorbed and desorbed above 5.5 mass % of H2 at 423K (8LiH ＋ 3Mg(NH2)2 3Li2.667MgN2H1.333＋8H2). We found that the H2 absorption and desorption of the MH-NH3 (M: Li, Na, K) system takes the following reaction path, MH + NH3  MNH2 + H2.
Effects of Alloying Elements on Mechanical Properties in Hyper-Eutectoid Steel Wires
Authors: Lee Jung Won , Kang Ui Gu , Lee Yong Shin , Park Kyung Tae , Nam Won Jong
Published: June 2010

The effects of annealing temperature and silicon content on mechanical properties on cold drawn pearlitic steel wires were investigated. Cold drawn steel wires, containing Si, 0.99 ~ 1.4%, were annealed at the temperature of 200 ~ 450°C with different annealing time. The variation of microstructural evolution with annealing temperature was not affected by silicon content. For steels containing high silicon content above 1.0%, the increase of silicon content did not cause the changes of peak temperature showing age hardening and age softening, except for the increase of tensile strength due to solid solution hardening.
Study of a Novel Ultra-High Strength Steel with Adequate Ductility and Toughness by Quenching-Partitioning-Tempering Process
Authors: Wang Ying , Zhou Shu , Guo Zheng Hong , Rong Yong Hua
Published: June 2010

According to the design principle of microstructures for high strength steel and a new quenching-partitioning-tempering (Q-P-T) process recently proposed by Hsu, a microalloying Fe-Mn-Si base steel by the Q-P-T process has been designed. The results indicate that the Q-P-T steel exhibits ultra-high tensile strength combining with good ductility and toughness, and it is a new family of advanced high-strength steels. The microstructures of samples by different Q-P-T processes were characterized by means of optical microscopy, scanning electron microscopy, X-ray diffraction and transmission electron microscopy, and the relation between microstructures and mechanical properties was analyzed
Compatibility Evaluation for Application of Lean Duplex Stainless Steels to Seawater Systems in Nuclear Power Plants
Authors: Chang Hyun Young , Park Heung Bae , Kim Young Sik , Ahn Sang Kon , Kim Kwang Tae , Jang Yoon Young
Published: June 2010

Lean duplex stainless steels have been developed in Korea for the purpose of being used in the seawater systems of industries. The flow velocity of some part of seawater systems in nuclear power plants is high and damages of components from corrosion are severe. Therefore, this environment requires using high strength and high corrosion resistant steels. The newly developed lean duplex stainless steels STS329LD(20.3Cr-2.2Ni-1.4Mo) and STS329J3L(22.4Cr-5.7Ni-3.6Mo) are evaluated for the compatibility in seawater systems of nuclear power plants. In this study, the physical & mechanical properties and corrosion resistance of two alloys were quantitatively evaluated in comparison with commercial stainless steel 316L. Microstructures and mechanical properties of them were analyzed and the electrochemical properties related to corrosion resistance were measured such as pitting potential, passive current density, and corrosion rates from Tafel analysis. Critical pitting temperatures were measured in accordance with ASTM G48E method. The pitting initiation time and lifetime for replacement were predicted from the PRE values of test alloys and empirical equations that have been formulated from the condenser tubes of a nuclear power plant.
Microstructural Characterization of Nb-Al Base ODS Alloys
Authors: Ukai Shigeharu , Minami Akinobu , Hayashi Shigenari , Sakaguchi Norihito , Miura Seiji
Published: June 2010

Nb, Al and Y2O3 powders were mechanically alloyed together with 5 wt% stearic acid. The heavy plastic deformation of the powders by mechanical alloying led significant hardening to 970 Hv and the reduced grain size to 10 nm. Nb-Al base ODS alloys consolidated by HIP at 1500 °C and 150 MPa for 0.5 h gave the dual phase of Nb solid solution and Nb3Al compound. The oxide particles are of the hexagonal type YAlO3 (YAH), with the size of 50 nm to 200 nm. The high-temperature ductility at 1200 °C and capability of the grain growth at 2000 °C were confirmed.
The Development of Mn-Series Air-Cooled and Water-Quenched Bainitic Steels in China
Authors: Fang Hong Sheng , Gao Gu Hui , Zheng Yan Kang , Yang Zhi Gang , Bai Bing Zhe
Published: June 2010

The origin and development of air-cooled Mn-series bainite steels are introduced. The invented idea, strengthening-toughening mechanism, mechanical performances, development and application of this kind of steel including granular bainitic steels, FGBA / BG duplex steels, CFB/M duplex steels, medium carbon bainite/martensite steels, cast bainitic steels are presented. The invented idea mechanical performances, development and application of second generation of Mn-series bainitic steels, i.e. water-quenched Mn-series bainitic steels invented by the authors newly are introduced. The water quenched Mn-series bainitic steels can meet the performance requirements of most steels used in engineering structure, reduce the amount of alloying content, increase harden capability and improve weldability. It should be pointed out that the application of both air-cold and water- quenched Mn-series bainitic steels are complementary and mutually reinforcing. Some newest technology of Mn-series bainitic steels in China are discussed in this paper. It is suggested that the significance of the development of the Mn-series bainitic steels can be summarized as: significantly reducing costs of both raw materials and production; good combination of strength and toughness; excellent weldability; simple procedure; large savings in energy resources and environmental pollution is reduced.
Aluminium-Rich Coring Structures in Mg-Al Alloys with Carbon Inoculation
Authors: Huang Yuan Ding , Zheng Xiu Hua , Okechukwu Anopuo , Kim Gyu Seok , Kainer Karl Ulrich , Hort Norbert
Published: June 2010

A homogeneous microstructure of as-cast magnesium alloys is necessary to improve the formability during their subsequent thermomechanical processing. In Al-containing magnesium alloys, the grain refinement by carbon inoculation is considered to be the best approach until now. However, the mechanism of grain refinement is unclear. The present work investigates the coring microstructure in Mg-Al alloys inoculated with carbon using FIB, SEM and TEM techniques. In each grain one or more “hillocks” exist, enriched with carbon, manganese and aluminium. This is possibly related to the inhomogeneous nucleation of alpha-magnesium. The precipitates in these “hillocks” are always surrounded by the aluminium-rich zones. These characteristics of microstructure observed in Mg-Al alloys with carbon inoculation are compared with that observed in Al-free magnesium alloys inoculated by zirconium. The similarities between them are discussed. A novel mechanism is suggested to explain the grain refinement in Mg-Al alloys inoculated by carbon.
Microstructure of Laser Treated ZE41A-T5 Magnesium Alloy
Authors: Durandet Yvonne , Sun S. , Brandt M.
Published: June 2010

Modification of the microstructure of ZE41A-T5 magnesium alloy substrates was investigated by laser surface re-melting and solidification using a 2.5 kW Nd:YAG laser. The effects of laser power, high scan rate and beam configuration were examined. The microstructure of laser treated ZE41 consisted of small precipitates dispersed in a fine dendritic α-magnesium matrix at high scan rates. The redistribution of chemical elements depended mainly on the dwell time in the liquid stage. At high scan rates, long dwell times were achieved by splitting the laser beam into two spots trailing in the scan direction which resulted in a more homogenous distribution of Mg, Zn and Zr. Cracking due to thermal shrinkage during solidification was prevented by reducing the temperature of the melt pool. This was achieved by lowering the laser power, increasing the scan rate and laser spot size. Increasing the laser spot size in the scan direction was conducive to producing homogeneous microstructures without cracks.
Spark Plasma Sintering of Ti-4.5Al-3V-2Fe-2Mo (SP-700)
Authors: Kikuchi Genki , Izui Hiroshi , Takahashi Yuya , Fujino Shota
Published: June 2010

In this study, we focused on the sintering performance of Ti-4.5Al-3V-2Mo-2Fe (SP-700) and mechanical properties of SP-700 reinforced with titanium boride (TiB/SP-700) fabricated by spark plasma sintering (SPS). TiB whiskers formed in titanium by a solid-state reaction of titanium and TiB2 particles were analyzed with scanning electron microscopy and X-ray diffraction. The TiB/SP-700 was sintered at temperatures of 1073, 1173, and 1273 K and a pressure of 70 MPa for 10, 30, and 50 min. The volume fraction of TiB ranged from 1.7 vol.% to 19.9 vol.%. Tensile tests of TiB/SP-700 were conducted at room temperature, and the effect of TiB volume fraction on the tensile properties was investigated.
The Effect of Temperature on the Microstructure of a Metastable β Ti Alloy
Authors: Wang Gui , Wang Wei Qi , Yang Yu Lan , Kent Damon , Dargusch Matthew S.
Published: June 2010

A metastable β titanium alloy, BTi-6554 (Ti-6Cr-5Mo-5V-4Al) has been developed for structural applications in aircraft because of its high strength, high toughness, and good fatigue properties. This paper reports on the effect of heat treatment on microstructure and microhardness of the alloy. It has been shown that in the as hot rolled condition, the alloy consists of a single β phase. Heat treatment between 450-750°C results in the precipitation of α laths, while exposure to temperatures between 700-800°C results in the gradual transformation of the α phase back to β phase with larger grain sizes resulting from higher heat treatment temperatures.
Plastic Deformation Characteristics and Evaluation of Press Formability for Ti-6Al-4V Sheet at Warm Temperature
Authors: Park Jin Gee , Park Nho Kwang , Kim Young Suk
Published: June 2010

Titanium alloy sheets have excellent specific strength and corrosion resistance as well as good performance at high temperature. Recently, titanium alloys are widely employed not only aerospace parts but also prosthetics and motorcycle. However, titanium and its alloys are difficult-to-form materials due to limited slip system and plastic anisotropy. Titanium alloy sheets were usually formed by slow forming or hot forming with heating die and specimen. In the sheet metal forming area, FE simulation technique to optimize forming process is widely used. To achieve high accuracy FE simulation results, identification of material properties and deformation characteristics such ad yield behaviors are very important. In this study, the yield locus of Ti-6Al-4V sheet was obtained at warm temperature. The experimental results are compared with the theoretical predictions. Also, the Forming Limit Curves (FLC) was achieved at warm temperature.
3D Transient Thermal Modelling and Experimental Validation of the Temperature Distribution during Laser Heating of Ti6Al4V Alloy
Authors: Yang Ji Hong Nancy , Sun Shou Jin , Brandt Milan , Yan Wen Yi
Published: June 2010

A three 3D transient finite element model has been developed to predict the temperature distribution in Ti6Al4V alloy plate workpiece. It is found that the temperature profile is strongly dependent on the parameters of the laser beam and material properties. Also the thermal model results were compared with results produced by experimental work and these show close agreement.
Dispersoid Phases in 6xxx Series Aluminium Alloys
Authors: Strobel Katharina , Sweet Elizabeth , Easton Mark , Nie Jian Feng , Couper Malcolm
Published: June 2010

In high strength AlMgSi alloys additions of Mn and Cr lead to the formation of dispersoid phases whose primary functions are to improve fracture toughness and control grain structure. Whether or not dispersoid phases form during heating to the homogenisation temperature and which dispersoid forms is strongly dependent on the alloy composition. By correlating dispersoid features after different homogenisation heat treatments to TEM investigations into the crystal structure, it is proposed that the crystal structure and chemical composition of the dispersoids changes as the dispersoids coarsen at increased temperatures and times.
Low-Cycle Fatigue Behavior of an Al-Mg-Si Alloy with and without a Small Addition of Sc
Authors: Watanabe Chihiro , Monzen Ryoichi
Published: June 2010

Low-cycle fatigue behavior of a wrought Al-0.8wt%Mg-0.7wt%Si alloy with and without 0.27wt%Sc has been investigated at room temperature under constant plastic-strain amplitudes. After peak-aging treatments, both the alloys had fine lath-shaped β' precipitates. In the Sc-containing alloy, spherical Al3Sc precipitates of about 11 nm in diameter were co-existed. The alloy with Sc exhibited cyclic hardening to saturation, while the alloy without Sc showed clear cyclic softening after initial hardening. Transmission electron microscopy observation revealed that slip band structures were developed in the Sc-free alloy. Within the slip bands, shearing of the β' precipitates by moving dislocations was often observed. The cyclic softening in the alloy without Sc can then be explained by a loss of precipitation strengthening effect through the precipitation destruction within strongly-strained slip bands. In the Sc-bearing alloy, owing to the existence of non-shearable Al3Sc precipitates, dislocations were uniformly distributed, resulting in the absence of the cyclic softening.
Effect of Electromagnetic Field on Horizontal Direct Chill Casting of 7075 Aluminum Alloy
Authors: Zhu Qing Feng , Zhao Zhi Hao , Wang Xiang Jie , Cui Jian Zhong
Published: June 2010

The influence of different electromagnetic fields on the horizontal direct chill (HDC) casting of aluminum alloy is studied. 7075 aluminum alloy with 100-mm in diameter is produced by HDC casting process; single electromagnetic field located before or around the mold and an out-phase electromagnetic field (OPEMF) are applied in the HDC casting process. The effect of different electromagnetic fields on the HDC casting solidification behavior and as-cast structure is investigated. The electromagnetic field can effectively make uniform thermal distribution in the molten pool and refine the as-cast structure. The OPEMF is more efficient than the single electromagnetic field in improving the as-cast structure of HDC cast ingots.
Optimum Control of Gyroscopic Systems
Authors: Hein Rafał , Orlikowski Cezary
Published: June 2010

The problem of optimal control of transverse rotor vibrations with gyroscopic interactions has been described and solved in the paper. An integral performance index has been defined for such system in order to minimize vibration level of a chosen rotor point. For this reason, an efficient way of establishing weight coefficients of integral performance index for multi-degree-of-freedom system with gyroscopic interactions has been described. Presented method enables to determine such weighing coefficients that selected modal forms would be assumed before dynamics properties and a performance index would took the minimum value. Computation results demonstrate that the proposed method is efficient and may be applied for complex mechatronic systems.
High Precision Mass Measurement in Automation
Authors: Ivanova Tatjana , Rudzitis Janis
Published: June 2010

High-precision mass measurement equipment is required in some areas of science and technology. Physics, chemistry, pharmaceutics and high precision mechanics are common examples. In metrology, high-precision scales are used for verification and calibration of lower precision mass measurement equipment (weights and scales). Mass comparators are the most accurate mass measurement instruments available today. It is a special type of electronic scales designed to compare mass of two weights. They can be automatic or manual, with various measurement ranges and accuracy classes. This article discusses principles of operation of mass comparators and practice of high-precision mass measurement. There are special computer programs that can be used in conjunction with these instruments, which may significantly improve measurement accuracy (when mass comparator is controlled remotely) as well as simplify calculations and reporting procedures. This article describes one of these programs – ScalesNet32 – which can be used with mass comparators produced by Sartorius (Germany).
Assembler Encoding versus Connectivity Matrix Encoding in the Inverted Pendulum Problem with a Hidden State
Authors: Praczyk Tomasz
Published: June 2010

Assembler Encoding is Artificial Neural Network encoding method. To date Assembler Encoding has been tested in the optimization problem and in the so-called predator-prey problem. The paper reports experiments in a next test problem, i.e. in the inverted pendulum problem. During the experiments two direct encodings were also tested in order to compare Assembler Encoding with other Artificial Neural Network encoding methods.
Research of Hydrotronic Variable-Displacement Radial Piston Pump with Electro-Pneumatic Control
Authors: Jasiński Ryszard
Published: June 2010

The paper presents the developed new electro-pneumatic control (pneumotronic) system for hydraulic fixed-displacement radial piston pump. Hydraulic fixed-displacement radial piston pump equipped with the proposed control system changes into hydrotronic variable-displacement radial piston pump. Pump flow rate control is realized by means of programmable logic controller, electro-pneumatic valves, pneumatic cylinders and a sensor.
Advanced Tools for Multi-Body Simulation and Design of Control Structures Applied in Robotic System Development
Authors: Kubela Tomas , Pochyly Ales , Singule Vladislav
Published: June 2010

The paper deals with a design of a 3-wheeled mobile robot based on Mecanum omnidirectional wheels. The 3D CAD geometry model was initially prepared with Pro-Engineer. The key issue with respect to design methodology reported in this research work is related to the application of co-simulation strategy. System ADAMS, intended for multi-body simulations, was used to evaluate dynamic behavior of the robot platform. MATLAB/Simulink was applied for testing the performance and control of structures. The co-simulation strategy consists mainly in application of ADAMS and MATLAB simultaneously, in one loop, utilizing its respective advantages. Further, as an alternative way to cover both multi-body and control aspects, Chrono::Engine system (by A. Tasora) was introduced in this work.
Calculation of Spectrum Characteristics for Braking Modes of Linear Induction Motors
Authors: Karaliunas Bronius , Matkevicius Edvardas
Published: June 2010

The purpose of the wok is to derive analytical expressions of spectral characteristics at electrical braking of linear induction motor with diverse number of poles as well as to provide results of calculations. The major task in the analysis of braking modes is to determine spectral characteristics of braking current, primary magnetic field and braking force. To this aim Maxwell equations were solved together with Fourier and Laplace integral transformations. The obtained results indicate that in addition to the main component of the magnetic field, when the space frequency is , in the process of braking there appears continuous spectrum of elementary components with the frequencies occupying the infinite sector from - to + . Due to that fact, during the process of energy conversion at the moment of braking, there participate positive – sequence, negative – sequence components and elementary components of the continuous spectrum, motionless in the space.
The Automation of Test Stand for Engine Cooling System Testing
Authors: Zbigniew Kneba , Śmieja Michał
Published: June 2010

The basic description of fully automated engine test stand is presented in the paper. The purpose of the stand is to perform evaluation of new generation cooling systems for combustion engines.
Effect of PWHT on the Mechanical Properties of P5 Steel Welded Joints
Authors: Kumšlytis Vigantas , Valiulis Algirdas Vaclovas , Černašejus Olegas
Published: June 2010

Presented work analyses the impact of heat treatment parameters on the mechanical properties and operational reliability of P5 (5%Cr0.5%Mo) steel welded joints. The key objects of research are heat-treated chrome-molybdenum steel welded joints and piping elements operated at high temperature for an extensive period of time, where degradation of mechanical properties has been observed. The main objective is to investigate the causes of degradation of alloy steel mechanical properties during fabrication and operation of the equipment, and to develop a methodology for identification of optimum heat treatment parameters for chrome-molybdenum steel welded joints. A few key issues are addressed herein: identification of dependence of chrome-molybdenum (5%Cr-0.5%Mo) steel welded joint mechanical properties on heat treatment parameters, identification of the optimum value of temperature/time parameter, and identification of causes of mechanical property changes and degradation of the steel.
Investigations of Production Processes of W-Re-Ni and W-Re-Ni-Fe Heavy Metals
Authors: Majewski Tomasz
Published: June 2010

Results of investigation of production process and properties of WReNi and WReNiFe sinters are presented in the paper. Methods for production of these sinters are described and exemplary pictures of their microstructures are provided. Mechanical properties of materials obtained from powders with different chemical composition are compared and discussed. Experimental results related to operational characteristics of these heavy metals intended for armor-piercing shell cores are presented.
Steel Strips Flattening in Ball Rolling Mill
Authors: Przondziono Joanna , Szymszal Jan
Published: June 2010

An effective and efficient production method of narrow and thin strips made of steel, non-ferrous metals and their alloys is wire flattening in a ball rolling mill. In this device cylindrical rollers have been replaced with balls of diameter ca. 15 mm. Proper selection of deformation process parameters enables to obtain strips with the required geometrical characteristics. Experimental planning method was applied to evaluate the influence of flattening process technological parameters on strip geometrical features. Statistical analysis enabled to determine mathematical models of stainless steel 5XCrNi18-10 strips flattening. It was established that strip widening depends on ball roughness, draft applied, relation of wire diameter to ball diameter, back-tension stress. Strips flatness depends on draft applied. It was observed that strips feature uniform thickness over their width, parallel flat surfaces, narrow dimensional tolerance, high quality surface and naturally rounded edges.
The Effect of Fabrication Method of Cobalt Base Clad Layer on Air Oxidation
Authors: Smolenska Hanna
Published: June 2010

The paper presents oxidation experiment with clad layers made of the cobalt base powder and prepared by the multi overlapped tracks and sublayers fabricated by means of plasma transferred arc (PTA) and laser cladding technologies. The oxidation processes were carried on at 1100 deg. C for 200 hours. In the course of investigation it was demonstrated that there were no evidence of influence of the fabrication method on the corrosion resistance of cobalt clad layers. The phase compositions of the scale were the same – generally Cr2O3 and similar tendency for cracking and spalling. In both cases changes in the layer under the scale also exhibited similar tendency – decomposition of the carbides from the interdendritic regions and severe internal corrosion along the dendrite boundaries.
The High Cyclic Failure Analysis of Welded Joints of CT Specimens
Authors: Stonkus Rimantas , Leonavičius Mindaugas Kazimieras
Published: June 2010

The results of failure process of welded joints subjected to high-cyclic loading are presented. Analysis of the microstructure of welded joints, indexes of mechanical properties are provided and failure mechanism in the area of fatigue and static fracture is analyzed. The fractographic analysis of CT specimens was performed by means of optical and scanning electron microscopes.
Influence of Cavitation Intensity on the Relative Cavitation Resistance of Laser Processed C45 Carbon Steel
Authors: Szkodo Marek
Published: June 2010

This work presents investigations of relative cavitation resistance of carbon steel (C45) at the initial stage of erosion, after melting its surface by 6 kW CO2 laser beam. The research work was carried out on the rotating disk facility. Three areas were determined on the surface of investigated sample. Each area was eroded with different intensity. The procedures were elaborated for calculation of resistance of processed surface to plastic deformation under cavitation loading and of relative intensity of cavitation using image analysis of monochromatic picture of eroded surface. The results indicate that increase of cavitation loading intensity results in decrease of relative cavitation resistance.
Critical to Quality Factors of Engineering Design Process of Armoured Vehicles
Authors: Koziołek Sebastian , Rusiński Eugeniusz , Jamroziak Krzysztof
Published: June 2010

Critical to quality factors of engineering design process of armored vehicles includes establishing the effects that defects have on the quality of mechanical objects as per engineering assessment criteria. Determination of the factors is an original part of work known as the Optimal Design For Six Sigma [9], which defines a defect as an inconsistency between parameters and the technical specification limits of the mechanical object. The basis for determining the common factors of the effects of defects is established through conducting surveys among users and establishing the significance of the engineering assessment criteria. Innovative product design based on the measurable quality factors and crucial for customers allows effective optimization of the object, and the ability to achieve a stable and optimal degree of product quality. In effect, this method enables to limit the occurrence of defects through preventive actions.
Theoretical and Experimental Analysis of Drawing of Square Wire and Square Twisted Wire
Authors: Suliga Maciej , Mróz Sebastian , Szota Piotr
Published: June 2010

Numerical analysis of drawing square and square twisted wires is presented. The thermomechanical simulation of the drawing process of square wire was carried out using the visco-plastic body model for a three-dimensional strain state with the use of Forge2007 software, while the properties of the material being deformed were described with the Norton-Hoff law. In this paper the distribution of effective strains and longitudinal stresses during changes of the cross- section and twisting of the wires has been demonstrated. It was determined that square twisted wires are characterized by significant inhomogeneity of strain. For verification of obtained numerical results experimental investigation was performed for square and square twisted wire drawing in laboratory conditions. The analysis of drawing stresses in square twisted wires used for modeling and experimental investigation indicated high material effort, which was much higher than in the case of drawing of square and round wires.
Numerical Modelling of the Microstructure during Rolling of Flat Bars
Authors: Szota Piotr , Stefanik Andrzej , Dyja Henryk
Published: June 2010

This paper presents theoretical analysis of microstructure changes in the material during standard rolling and normalizing rolling of the 35x20 mm flat bars. The analysis was carried out by means of computer software Forge 2007® that is based on finite element method. Two cases of accelerated cooling during rolling process were considered. Numerical results of 35x20 mm flat bars rolling process allowed to determine the average recrystallized austenite diameter as well as basis energy and force parameters. Proposed modification of the 35x20 mm flat bar rolling technology with accelerated cooling results in the reduction of average austenite diameter, which could improve the strength of the final product.
Continuing Perfection of Industrial Engineering and Management Knowledge after Master Studies
Authors: Jančiauskas Bronius , Toločka Eligijus
Published: June 2010

Qualitative high education of a country is one of the most important factors that ensure a sustainable development of a respective country. Therefore effective development of higher education in the country becomes a significant factor in achieving this goal. Faster development of industry is mostly affected by the training of qualified industry engineers at higher education schools based not only on the conveyance of engineering, but also of managerial knowledge and the development of their abilities. The objective of this article is to put forward measures for improving continuing master studies in industrial engineering and management.
Camptocormia in Parkinson's Disease
Authors: Abe Kazuo , Uchida Yutaka , Notani Masaru
Published: June 2010

Objectives. Abnormalities of posture represent one of the main features of Parkinson's disease (PD). Among them, camptocormia has been considered as rare in PD. We investigated frequency and clinical features of camptocormia in PD patients.Methods. 153 PD patients (mean years old, duration years) outpatiently recruited. After neurologic examination, patients were rated on the Unified PD Rating Scale motor scale (UPDRS Part III), minimental state examination (MMSE). Also we evaluated patients with camptocormia by MRI. Of the 153 PD patients, 27 had camptocormia (mean age, years old; disease duration, years). For further evaluation, we recruited age- and sex-matched 27 PD patients without camptocormia (11 men and 16 women; mean age , years, duration years) These selected 54 patients completed several self-assessments. Lumbar and thoracic paraspinal muscles were studied by EMG.Results. There were no significant differences in age, duration, severity, and drug dose between patients with and without camptocormia. Analysis of NMSS subitems indicated that PD patients tended to show lower scores for sleep/fatigue, attention/memory, and miscellaneous items.Conclusions. We found significant differences concerning nonmotor signs and symptoms evaluated by FAB, PDQ-8, FSQ, VAS-F, and NMSS between patients with and without camptocormia. Our findings indicate that camptocormia is a relatively common sign in PD and that patients with camptocormia scores on the PDQ-8 compared with PD patients without camptocormia. This suggests that improvements in camptocormia of PD patients may improve their QOL.