bluuebunny/crossref_metadata_2025 huggingface dataset:
Recrystallisation Texture of Cold Rolled and Annealed IF Steel Produced from Ferritic Rolled Hot Strip
Authors: Elsner A. , Kaspar Radko , Ponge Dirk , Raabe Dierk , van der Zwaag Sybrand
Published: March 2009

The ferritic rolling strategy allows for the production of two different hot strip grades, a "soft" and a "hard" hot strip. The "soft" hot strip is rolled in the upper ferrite region and a sufficiently high coiling temperature ensures direct recrystallisation in the coil. The "hard" hot strip is rolled at relatively lower temperatures in the ferrite temperature region and exhibits a strained microstructure with a desirable rolling texture. Furthermore, these ferritic rolled hot strips can be used as initial strip for subsequent cold rolling. The current investigation focuses on the development of the recrystallisation texture of cold rolled and annealed ferritic rolled hot strip for different cold reductions. For this purpose "soft" and "hard" hot strips were produced on a laboratory hot rolling mill. These strips were cold rolled with a total reduction of 40 to 80% to a final thickness of 0.5mm. Subsequently the strips were subjected to simulated continuous annealing, using a salt bath furnace. The macro texture of both types of specimens was measured and correlated to the mechanical properties, including the Lankford values. A very different development of the recrystallisation texture and hence mechanical properties has been observed. However, both grades yielded improved deep-drawing properties.
An Impingement – Spheroidisation Theory for Nucleation and Grain Growth
Authors: Duggan B.J. , Tse Y.Y. , Shen G.J.
Published: March 2009

In an investigation of nucleation of recrystallisation in an Interstitial Free steel it was found that new crystals were almost always contained within the rolled-out hot band grain envelopes and were mostly equiaxed. At a later stage they grew and had an aspect ratio of 2:1 but at the completion of recrystallisation were again equiaxed. This is explained by the notion that nucleation occurs relatively frequently in certain grains, that these nuclei have very similar orientations and are thus orientation pinned within the solute and precipitate containing envelopes of the hot band grains. Provided the misorientation is small the impinged group are capable of spheroidisation provided the driving force across the pinned boundary is sufficient to overcome the pinning, because, by definition, this pinned boundary is of high angle character. The theory, as it is presented as coalescence, relies on a form of Östwald ripening and therefore provides a possible explanation of why grain growth kinetics obeys a time exponent of between 1/2 and 1/3. A similar observation of high aspect ratio grains has been made many times in the case of cold rolled copper which forms cube texture. Again, nuclei are formed in the cube bands, but these are prevented from lengthening because of orientation pinning. However, when the length of a group of such impinged nuclei is sufficient, spheroidisation will produce equiaxed grains.
In-Grain and Grain-to-Grain Textural Inhomogeneities in Coarse-Grained Tantalum
Authors: Sandim Hugo Ricardo Zschommler , Martins J.P. , Pinto Andre Luiz , Padilha Angelo Fernando
Published: March 2009

The recrystallization behavior of coarse-grained tantalum deformed at large strains is strongly dependent on its deformation microstructure. In this regard, a longitudinal section of a high-purity coarse-grained tantalum ingot obtained by double electron beam melting (EBM) was rolled at room temperature to thickness reductions varying from 70 to 92% followed by annealing in vacuum at 900 and 1200°C for 1 h. Microstructural characterization was performed in cold-rolled and annealed specimens using scanning electron microscopy (SEM) in the backscattered mode (BSE), electron backscattered diffraction (EBSD), and microhardness testing. Results show that recrystallization of individual grains is strongly dependent on the initial orientation. In consequence, recrystallization kinetics varies noticeably from one grain to another. Inhomogeneous in-grain and grain-to-grain spatial distributions of textures are found in the tantalum plates. Texture components belonging to the so-called g fiber ({111}// ND) are in majority in the rolling plane. The presence of tiny recovered regions in the annealed plate is associated to stable orientations like rotated cube {001}<110>, which are very resistant to recrystallization even at high annealing temperatures. EBSD results also confirm the occurrence of growth selection during recrystallization in coarsegrained tantalum.
Modeling of Nucleation Spectra for Primary Recrystallization and Application to Through-Process Texture Modeling
Authors: Crumbach Mischa , Goerdeler Matthias , Gottstein Günter
Published: March 2009

Schemes to model deformation inhomogeneities and nuclei distributions based on the
grain cluster model for deformation texture simulation GIA are presented. The orientation distributions of nuclei in stable orientations, nuclei in grains with orientation gradients and nuclei due to subgrain growth at grain boundaries are predicted. Additionally, nuclei with a random orientation distribution are considered, reflecting nucleation at shear bands or large constituent particles. Furthermore,
models for a quantitative assessment of the participating nucleation mechanisms are proposed. The resulting nucleation texture was input to the static recrystallization texture model StaRT. The through-process texture development during a sequence of several hot rolling, cold rolling and annealing steps in industrial production of the aluminum alloy AA5182 is presented.
New Understanding of Abnormal Grain Growth Approached by Solid-State Wetting along Grain Boundary or Triple Junction
Authors: Hwang Nong Moon
Published: March 2009

Although it has been generally believed that the advantage of the grain boundary mobility induces abnormal grain growth (AGG), it is suggested that the advantage of the low grain boundary energy, which favors the growth by solid-state wetting, induces AGG. Analyses based on Monte Carlo (MC) simulation show that the approach by solid-state wetting could explain AGG much better than that by grain boundary mobility. AGG by solid-state wetting is supported not only by MC
simulations but also by the experimental observation of microstructure evolution near or at the growth front of abnormally growing grain. The microstructure shows island grains and solid-state wetting along grain boundary and triple junction.
In-Situ Observations on Interphase Boundary Migration and Grain Growth during α/γ Phase Transformation in Iron Alloys
Authors: Watanabe Tadao , Obara Kouichi , Tsurekawa Sadahiro
Published: March 2009

In-situ observations of a/g phase transformation were made to study the effect of grain boundary microstructure of the generation of a new phase and the migration of a/g interphase boundaries in an Iron-4.2at.%Cr alloy. It was found that triple junctions with more random boundaries could be the primary nucleation sites, while triple junctions with low angle and low S coincidence boundaries did not play a role as preferential sites. The migration of a/g interphase boundaries during heating across the transformation temperature showed the two stage behaviour characterized first by a stage with a migration velocity of 0.33-0.75µm/s and secondly a stage with 3.7-7.6 µm/s. It was also found that abnormal grain growth and a high density of S3 coincidence boundaries could occur in the a/bcc phase after cycling of a/g/ a phase transformation.
Results from In-Situ, Real-Time SEM Observations of Grain Growth in Polycrystalline Metal
Authors: Fielden I.M.
Published: March 2009

The development of the converter plate detector has allowed the generation of real-time, in-situ image sequences of evolving microstructures in model and industrial polycrystalline metals. The principal metals investigated were steel, aluminium and gold. The raw video results allow a number of qualitative statements to be made about grain growth behaviour in these systems and some simplistic quantitative statements. However, the sheer volume and variety of data available in the time-stream of micrographs presents its own problems in identifying and extracting the
information most useful for rigorous characterisation of the behaviour of a dynamically evolving microstructure. We present and discuss our approach to the analysis of this data and results of that analysis.
Comparison of the Morphological Effect for the Simulation of Abnormal Goss Grain Growth in Two Fe-3%Si Alloys, Grades Hi-B and CGO
Authors: Maazi N. , Rouag N. , Penelle Richard
Published: March 2009

A grain growth simulation based on the concept of grain boundary migration driven by the radius curvature has been tested to study the abnormal grain growth (AGG) of the Goss grains in silicon steels in presence of particles. In the classical simulation of AGG, the grain size is generally assumed to be homogeneous. In order to introduce the influence of the morphological and
crystallographic heterogeneities on AGG around the Goss grain, the simulation procedure has been implemented using as starting state an experimental microstructure characterized by Orientation Imaging Microscopy (OIMTM). Abnormal growth results are compared for the two grades, Hi-B and CGO of Fe-3%Si alloys. It has been notably shown that the large grains resist AGG so that the Goss grain shape becomes anisotropic.
Mechanical Properties and Microstructure of Self-Lubricating Ceramic Cutting Tool Materials
Authors: Deng Jian Xin , Cao Tong Kun , Sun Jia Lin
Published: March 2009

Al2O3/TiC ceramic tool materials with the addition of solid lubricants such as BN and
CaF2 were produced by hot pressing. Effect of the solid lubricants on the microstructure and mechanical properties has been studied. Results showed that AlN phase resulted from the reaction of Al2O3 with BN was formed in Al2O3/TiC/BN composite after sintering. Significant micro-cracks resulted from the residual stress owing to the difference in the thermal expansion coefficient were found on the polished surface, and caused large mechanical properties degradation. While Al2O3/TiC/CaF2 composite showed higher flexural strength, fracture toughness, and hardness compared with that of Al2O3/TiC/BN composite owing its porosity absent and finer microstructure.
Microstructure and Mechanical Properties of two Kinds of Al2O3/SiC Nanocomposites
Authors: Liu Han Lian , Huang Chuan Zhen , Wang Jun , Sun Jing
Published: March 2009

Two kinds of Al2O3 /SiC nanocomposites with different alumina powder are developed, one is fabricated only by nano-scale alumina powders, the other is by micro-scale with partial nano-scale alumina powders. Both of the two composites may get higher flexural strength and fracture toughness than that of micro-scale monolithic alumina ceramics, but the latter is more preferable than the former. The microstructure and the strengthening and toughening mechanisms of the new ceramic tool materials are investigated, the improvement of mechanical properties may be mainly attributed to the transgranular fracture mode induced by the added nano-scale SiC, while adding nano-scale alumina powder to micro-scale powder, both of the nano-scale Al2O3 and nano-scale SiC may strengthen the micro-scale Al2O3 matrix, that means the nano-scale Al2O3 acted as the dispersed phase.
Optimal Control of Active Ambulance Stretcher Suspension
Authors: Sun L.L. , Song K.J.
Published: March 2009

A theoretical model of two-dimensional active control for ambulance stretcher suspension is proposed. The shaping filter equations of time domain are developed to provide optimal estimates of the disturbance dynamics. Numerical calculations are carried out to examine the effectiveness of proposed control scheme. It shows that the optimal control with disturbance feed-forwarded provides significant reduction of vertical and pitch vibration transmission compared with the passive stretcher suspension. The relative displacement and resonance peak values of vibration components in the sensitive frequency range of human body are effectively suppressed in comparison with that of the 1-DOF active control stretcher.
Study on the Thrust Cutting Force in Ultrasonic Elliptical Vibration Cutting
Authors: Ma Chun Xiang , Shamoto Eiji , Moriwaki T.
Published: March 2009

In the present paper, the thrust cutting force model in ultrasonic elliptical vibration cutting is proposed based on the principle of ultrasonic elliptical vibration cutting, and the reason of the thrust cutting force reduced by applying ultrasonic elliptical vibration is clarified theoretically. The effect of ultrasonic elliptical vibration on the thrust cutting force is verified experimentally.
Evaluation and Measurement of Surface/Subsurface Crack Damage of Ground Ceramics
Authors: Lin Bin , Zhu Hong Tao , Wu Hui , Wang Z.F. , Yu S.Y.
Published: March 2009

While be ground, ceramic is prone to engender surface/subsurface crack damage layer because of great grinding force and high brittle of the material. The crack damage layer was investigated in this research. In experiment, it is observed that the surface/subsurface crack damage layer consists of three kinds of cracks: surface micro-cracks, surface macro-cracks and subsurface crack system. To evaluate expediently the degree of damage to the machined components, the index of surface/subsurface crack damage - Dc, is defined.
Wrinkling Limit Based on FEM Virtual Experiment during NC Bending Process of Thin-Walled Tube
Authors: Li Heng , Yang He , Zhan Mei , Guo L.G. , Gu R.J.
Published: March 2009

A definition of forming limit is given with minimum centerline radius min R before wrinkling for NC bending process of thin-walled tube. Based on the developed FEM wrinkling prediction system TBWS-3D, an effective searching algorithm of wrinkling limit is proposed and forming limit can be obtained conveniently. Thus influence laws of main forming parameters on wrinkling limit are investigated and revealed. Measures to improve forming limit is put forward consequently. The achievements may help to both practice of thin-walled precise tube bending and research of plastic wrinkling.
A Monitoring System of Drill Wear States Using a Hybrid Neural Network
Authors: Karri V. , Kiatcharoenpol T.
Published: March 2009

A reliable and sensitive technique of cutting tool condition monitoring in drilling is essential help for practising engineers. It is commonly known that a worn drill bit produces a poor quality hole. In extreme cases, a catastrophic failure of a drill bit during cutting can destroy a work-piece and damage a machine tool resulting in low productivity and expensive down time To detect the states of cutting tool wear condition, attempts are made to physically measure wear land. An intelligent system for detecting wear condition without interrupting the process is essential to avoid unexpected cutting tool breakage. In this work, an intelligent algorithm is proposed to real-time monitoring of drill wear states, in the form of a digital display, over a comprehensive range of cutting conditions. A novel neural network, Hybrid Neural Network (HNN), was developed and tested in this task. The results of the HNN have shown the ability to accurately monitor the wear states up to a 92% success rate. With such a highly accuracy of results, the developed system can be used for monitoring wear states in drilling and warning operators.
A New Parallel Robot for Steel Snagging
Authors: Feng B.F. , Shi Hong , Cai Guang Qi
Published: March 2009

Kinematics, workspace, dynamics behavior of a 3-DOF 3-Legged parallel robot with
horizontal slide 3-link for steel snagging, which was developed by Northeastern University, are introduced. The steel spot snagging experiments have also been carried out. The wheel selection, removal rate, grinding power and their influence factors are studied. Comparing with hanging grinders used in most steel mills of our country, this robotic grinder can reduce labor intensity of workers, raise efficiency and guarantee quality greatly.
Experimental Study on the Milling of a High Strength Titanium Alloy
Authors: Geng Guo Sheng , Xu Jiu Hua , Ge Ying Fei , Fu Yu Can
Published: March 2009

A series of experiments were carried out on normal and high speed milling of a high
strength titanium alloy (TA15). TA15 is a close alpha titanium alloy strengthened by solid solution with Al and other component. It is often used to make large structural parts in airplane and welded parts subject to heavy load. The tool life of several typical types of cutter commonly used in the milling of titanium alloy was studied by the orthogonal experiment design method. After multi-element regression analysis, the empirical equation of the tool life was stablished. The milling force and temperature were measured under different cutting conditions and tool wear status. The knowledge is useful to further understand and analysis of the cutting mechanism, machining quality and tool wear. The study on the machined surface integrity includes the following content: surface roughness, metallographic examination, work hardening and residual stress.
Research on Precision Forging Law of Complicated Blade by Using 3D FE Simulation and Physical Modeling
Authors: Zhan Mei , Yang He , Liu Yue Lian
Published: March 2009

Research on precision forming laws of complicated blade has been a challenging issue on international frontiers of plastic forming areas. The precision forging laws of the blade with a damper platform have been obtained by using 3D FE simulation and physical modeling. The laws involve in the deforming characteristics of the tenon, damper platform, middle blade body, and tip blade body, such as the unevenness of deformation and material flow, the branch-flow of material, material flow characteristic of the blade body and rotation forming characteristic of the damper platform. The research may serve as a guide to the optimization design of relevant process and dies.
Copper Coating by Electroless Process for Aluminium Matrix Composite
Authors: Tomolya Kinga , Gácsi Zoltán , Kovács Árpád
Published: March 2009

The central problem of producing of Al/SiCP composites is to avoid the forming of brittle Al4C3, which leads to a poor corrosion resistance and degraded mechanical properties [Mingyuan, 1999]. The possible way is the covering of the SiC particles. This paper deals with the covering of SiC. The coated particles will be applied for producing aluminium matrix composites. We have covered three different grain sizes of particles. We have applied the nonelectrolytic method of deposition from solution for coating. Before the covering the surface needs to be catalysed. We have compared the effects of different type of catalysators, then we have analysed the effects of plating time by means of the scanning electron microscopy.
Producing of Singlecrystal from Heusler Alloy
Authors: Veres Zsolt , Roósz András
Published: March 2009

The Heusler alloy is a ferromagnetic compound (Cu2MnAl), that is suitable for the simultaneous monochromatization and polarization of the neutron beam in the form of singlecrystal. The prespecimen were cast in shell-sand or permanent steel moulds, then they were resolidified in crucibles of different size and material in the Universal Multi-zone Crystallizer (UMC) developed in the Institute of Material Sciences of Miskolc University. The solidified samples were investigated by means of a light microscope, electron microscope, energy disperse microprobe, X-ray diffraction as well as neutron scattering experiments.
Investigation of Thermomechanical Treated Austenitic Stainless Steel
Authors: Nagy E. , Mertinger Valéria , Tranta Ferenc , Sólyom Jenő
Published: March 2009

During thermomechanical treatment of austenitic stainless steel a’ martensite and e
martensite form in the austenite matrix. The martensitic transformation and deforming existing together result a high elongation at the investigated steel belonging to the TRIP grades. The amount of a’and e martensite depends on the strain level as well as on the deforming temperature in this steel. In the course of thermomechanical treatments we measured the amount and texture of the existing phases at different temperature and strain. It has been stated that the martensites are dominant in low temperature range, they have a considerable amount, and the transformation from e
martensite to a’ martensite also takes place. The amount of a’ martensite increases by increasing the strain while the amount of e martensite shows a maximum. By investigating the relationship between the quantity of existing phases and the effect of texture, it has been stated that the transformation takes place in certain given plates in the textured matrix.
Interaction between a Titanium-Containing Molten Salt and an Alumina Plate
Authors: Baumli P. , Sytchev J. , Göndör Zs.H. , Kaptay György
Published: March 2009

In the present paper the chemical interaction between an alumina plate and a one-phase NaCl-KCl-K2TiF6 as well as two-phase NaCl-KCl-K2TiF6/Ti system has been studied experimentally at 700 oC during 2 hours, as function of K2TiF6 content of the melt. In all experiments the reaction product TiO2 of an exchange reaction has been found at the surface of the alumina plate. Its thickness changes through a maximum point as function of the K2TiF6-content of the melt, as a result of the competition of two processes: the exchange reaction leading to the formation of the TiO2 layer, and its dissolution in the melt.
Stability of SiC in Al-Rich Corner of Liquid Al-Si-Mg System
Authors: Yaghmaee Maziar Sahba , Kaptay György
Published: March 2009

The thermodynamic analysis of the SiC/Al-Si-Mg system has been performed in order to find the conditions to produce SiC/Al-Si-Mg composite materials with the stable SiC/alloy interface (for both a-SiC and b-SiC) and with the solidification of primary a-Al solid solution. The conditions to avoid the formation of Al4C3 are expressed as function of temperature, and the silicon and magnesium content of the liquid aluminium alloy. It has been shown that to ensure stabilization of (the more stable) b-SiC, lower Si-content is needed and higher working temperature is allowed, compared to the requirements to stabilize (the less stable) a-SiC.
The Role of Niobium in Cold Rolled TRIP Steel
Authors: Hulka Klaus
Published: March 2009

In the recent years several new high strength steel grades have been developed, which exhibit improved cold formability and thus are especially suitable for the car body. These multi-phase steels have to be processed via continuous annealing lines. The best combination of strength and uniform elongation is obtained with ferrite-bainite-retained austenite multiphase steel, which rely on transformation induced plasticity (TRIP effect) during the cold forming operation. The production route for TRIP steel, which relies on two isothermal heat treatments, is explained as well as the role of the major alloying elements. In order to optimize the property
combinations, microalloying with niobium is a successful means. Niobium increases the strength of the steel with 15 MPa per 0.01 %Nb and simultaneously provides also a higher amount of stable austenite, thus guaranteeing both, increased strength and formability. The metallurgical background for providing these results is explained. Even though the amount of high strength steel in automobiles is continuously increasing, the application of TRIP steel is still limited. However, the good experience in trials and first successful applications make an increased usage of this steel type also realistic, despite its relatively high production costs and reduced weldability.
Preparation and Characterization of Pb(Zr,Ti)O3 Films on SrTiO3 Substrates
Authors: Gong Wen , Li Jing Feng , Chu Xiang Cheng , Li Long Tu
Published: March 2009

Pb(Zr,Ti)O3 (PZT) thin films have attracted great attention due to their superior
ferroelectric, pyroelectric and piezoelectric properties. The epitaxial films on single-crystal substrates are expected to possess enhanced properties compared with polycrystalline films on conventional silicon wafers. We prepared epitaxial PZT films on STO (STO) substrates with different orientation by using a sol-gel method. The preparation parameters were optimized to improve crystallization of the films. Although the films were of the same composition and prepared under the same condition, different crystal phases with corresponding preferential film orientations were formed when the substrate orientation was changed. [001]-oriented tetragonal PZT film was formed on the {100} surface of the STO substrate, whereas [111]-oriented rhombohedral PZT film on the {111} surface.
Influence of AC-Voltage on the Crystallization of Amorphous Silicon Thin Film during Field Aided Lateral Crystallization Process
Authors: Choi Sung Hwa , Kim Young Bae , Wang Yu Hang , Choi Duck Kyun
Published: March 2009

In field aided lateral crystallization process which is one of the low temperature crystallization processes for the amorphous silicon films, the effect of the alternating field (AC voltage) instead of the static field (DC voltage) was investigated.
Following the deposition of 2 nm thick Cu catalyst outside of the 5 mm bar patterns in the PECVD amorphous silicon film, the specimen was heated at 500°C in N₂ambient for 5 hours with applying 5 V/cm AC-field along with 30 V/cm DC-field. As compared to the case of 35 V/cm DC-field only, the specimen from both the 30 V/cm DC and 5 V/cm AC resulted in 1.5 times faster crystallization velocity, regardless of the experimental frequency ranges of 100 Hz ~ 50 MHz. Presumably, the enhancement of the crystallization velocity under the combined field is associated
with the increase in the flux of the crucial diffusion species, Cu atoms, which govern the overall crystallization velocity due to the agitation effect by the AC-field.
Intermetallic Formation between Sn-Ag(-Cu) Solder Bumps and Au/Ni/Ti UBM and It’s Effects on the Shear Force of the Solder Bumps
Authors: Park Se Hoon , Kim Young Ho
Published: March 2009

The shear force of Sn-3.5Ag and Sn-3.8Ag-0.7Cu solder bumps formed by the stencil printing method was measured and the effects of intermetallic formation on the shear force of solder bumps were investigated. The Sn-Ag(-Cu) solder paste was printed on the Au/Ni/Ti under bump metallurgy (UBM) and then reflowed repeatedly. The shear force of the solder bumps was measured as a function of the reflow times. The intermetallic formation in the Sn-Ag(-Cu) solder/UBM was
characterized using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and x-ray diffractormeter. Ni3Sn4 phase was formed in the Sn-3.5Ag solder/UBM interface and (Cu,Ni)6Sn5 phase formed at the Sn-3.8Sg-0.7Cu solder/UBM interface. The shear force of solder bumps was sensitive to the depletion of Ni layer and the intermetallic thickness at the solder/Ni interface. The shear forces of Sn-3.5Ag solder bumps decreased rapidly after the fifth reflow due to the depletion of Ni layer in the UBM. The shear forces of Sn-3.8Ag-0.7Cu solder bumps decreased after the tenth reflow due to extensive growth of intermetallic layer in the solder/Ni interface.
The Dynamic Impact Behaviors of NiTi Alloy
Authors: Xu Ren Bo , Cui Li Shan , Zheng Yan Jun
Published: March 2009

The contact force during impact of a NiTi alloy was studied in this paper. The contact force and contact time during impact between a spherical impactor and the specimen at different impact velocity and temperature were measured in real time. The maximum contact force and contact time of the NiTi alloy in the martensite state increased and decreased respectively with increasing temperature. The maximum contact force of the NiTi alloy in the parent phase state showed a plateau with increasing impact velocity of the impactor.
The Effect of Rapidly Solidified Microstructures on the Martensitic Transformation in Ti50-Ni45-Cu5 Shape Memory Alloys
Authors: Kim Yeon Wook , Nam Tae Hyun
Published: March 2009

Transformation behaviors and shape memory characteristics of Ti–Ni45-Cu5 alloy ribbons prepared by melt spinning were investigated by means of DSC, XRD and OM. In these experiments particular attention has been paid to change the ejection temperature of the melt from 1400°C to 1600 °C. As the results, the thickness of ribbons could be controlled. An increase of the superheat of the melt leads to a reduced ribbon thickness and a refinement of grains. The microstructural refinement
and the increased internal strains achieved by controlling the melt-spinning temperature decreased Ms significantly. It was also found that two-step transformation (B2-B19-B19’) occurred in the ribbons fabricated at higher melt-spinning temperatures than 1450°C.
Influence of Rare Earth on Shape Memory and Martensitic Transformation Behaviors of a FeMnSiCr Alloy
Authors: Huang Xing , Chen Shipu , Hsu T.Y.
Published: March 2009

Proper amount of blend rare earth (RE), e.g. less than 0.2 wt%, was added into a
Fe25Mn6Si5Cr alloy and showed beneficial effect on its shape memory property. On the other hand, measurements of internal friction revealed that RE-addition reduces the Ms temperature and the amount of thermal-induced martensite. Higher La-content in thin hcp (e) plates than that in fcc (g) matrix was observed by analytical TEM. Thermodynamic calculations also indicated a relatively high
equilibrated concentration in e and a strong interaction between La atom and 1/6<112> Shockley dislocation. Except for the grain refinement and solid-solution strengthening effect, the influence of RE on the g ® e martensitic transformation is discussed in taking into account both the Suzuki Effect and Suzuki Lock. The former results in a reduced stacking fault energy, while the Suzuki Lock hinders the movement of Shockley partials and thus the extension of stacking faults.
Shape Memory Effect in Co-Ni Polycrystalline Alloys
Authors: Zhou Wei Min , Liu Yan , Jiang Bohong , Qi Xuan
Published: March 2009

Co-Ni alloys exhibit g(fcc)®e(hcp) martensitic transformation and show reversible induced strain under applied magnetic field, which means they are potential magneto-shape-memory materials. Polystalline of Co-Ni alloys with varied Ni content were prepared. The g(fcc)®e(hcp) martensitic transformation and shape memory effect (SME) of Co-Ni alloy were studied. The influences of Ni content and deformation temperature on SME were discussed. The shape recovery
rate and recoverable strain decrease with the increase of Ni content.
Axial Compressive Behavior of Single-Stage Bellows of TiNi Shape Memory Alloy for Seismic Applications
Authors: Semba Hiromasa , Okabe Nagatoshi , Yamaji Toru , Okita Keisuke , Yamauchi Kiyoshi
Published: March 2009

The bellows formed of TiNi shape memory alloy (SMA) is proposed as a new type of seismic protection device. The bellows structure is known to have lower rigidity along the axial direction through effect of its shape. TiNi is known to be one of the most typical SMAs, which have high damping characteristics for dynamics engaged in its twin formation under martensite state and have the ability to recover completely from the large strain after unloaded and or heated. In this study, fundamental compressive behavior of TiNi bellows was investigated and discussed. Several shapes of TiNi single-stage bellows produced by rubber bulge method were prepared. They were heat-treated for some heat treatments and then examined on compression tests. Based on the results, the relationships among the bellows shapes and the stiffness, energy-absorbing capacity and so on were clarified. Finally, it was found from these results that single-stage bellows of TiNi SMA could
be used as one of seismic protection devices.
Processing of Single-Stage Bellows of TiNi Shape Memory Alloy Using Rubber Bulge Method
Authors: Semba Hiromasa , Okabe Nagatoshi , Yamaji Toru , Okita Keisuke , Yamauchi Kiyoshi
Published: March 2009

The bellows formed of TiNi shape memory alloy is proposed as a new type of seismic protection device. The bellows structure is known to have lower rigidity along the longitudinal direction through effect of its shape. On the other hand, TiNi is known to be one of the most typical shape memory alloys, which have high damping characteristics for dynamics engaged in its twin formation under martensite state and have the ability to recover completely from the large strain (even such as 8%) after unloaded and or heated. This paper describes a processing method of a single-stage bellows of TiNi shape memory alloy using rubber bulge method. Thin-walled TiNi tubes subjected to cold working were prepared. Several annealing conditions for the process were examined and the appropriate one was discussed. Then the rubber bulge method of displacement control was introduced. Finally, the procedure of the process including heat treatment was clarified.
Magnetic Structure and Magnetization Reversal in Nanocomposite Pr2Fe14B/α-Fe Ribbons
Authors: Bao Xiaoqian , Zhang Mao Cai , Qiao Yi , Zhou Shouzeng
Published: March 2009

Nanocomposite Pr7.5Dy1Fe71Co15Nb1B4.5 ribbons were prepared by melt-spinning and subsequent annealing. Interaction domains were imaged using magnetic force microscopy (MFM) because of strong exchange coupling between hard and soft magnetic grains. Coercivity was determined by exchange coupling pinning field. But the magnetization reversal of nanocomposite magnets were different from that of traditional single phase permanent magnets.
Mössbauer Spectrometry Study of Spinodal Decomposition in Fe-25Cr-12Co-1Si Alloy during Step Ageing
Authors: Xu C.Y. , Zhen L. , Sun X.Y. , Xu R.G. , Gao R.S. , Zhang X.M.
Published: March 2009

The local environment issued from the phase decomposition in Fe-25Cr-12Co-1Si alloy during step ageing has been studied by 57Fe Mössbauer spectrometry. The phase decomposition is influenced by both ageing time and temperature. It processes rapidly when ageing temperature is high. The formation of different kinds of (Fe, Co)-rich, Fe-rich and Cr-rich domains with independent hyperfine parameters during phase decomposition was characterized by hyperfine field
distribution. The magnetic hardening of the alloy was discussed basing on single domain particle model.
Effect of Substitution of Magnetic Metal Ions on Magnetic and Magnetoresistance Properties in LaSr2Mn2O7
Authors: Feng J. , Bo Q.B. , Che P. , Wang J.P. , Lu M.F. , Liu J.F. , Cao Xue Qiang , Meng Jian
Published: March 2009

The layered manganese oxides LaSr2Mn2-xTxO7 (T=Fe, Cr and Ni) has been prepared. The effect of substitution of transition metal ions for Mn on magnetic and magtoresistance properties has been studied. The compound has a tetragonal symmetry and the lattice parameters a decreases with increasing the doped content but the parameter c increases with x. It indicates that the MnO6 octahedron increase the distortion with x content. With the x increase, their ferromagnetic property was depressed. The Neel temperature TN was depressed gradually from 138K to 89K, 95K and 85K at x=0.3 for T=Fe, Ni and Cr respectively. Their magnetoresistance MR is gradually enhanced for all doped system. It suggests that the introduce of disorder in B-site have an important effect on the magnetic exchange and magnetoresistance because of the weaken of the double-exchange (DE) interaction.
Dynamic Characteristics of Tb-Dy-Fe Polycrystals with <110> Axial Alignment
Authors: Wang Bo Wen , Weng L. , Li S.Y. , Zhou S.Z. , Gyuro I.
Published: March 2009

The magnetostriction and dynamic characteristics of Tb0.27Dy0.73Fe2 polycrystals with <110> axial alignment were investigated by standard strain gauge, two coil induction and lock-in amplifier techniques. It is found that the magnetostriction of the sample quickly increases with increasing magnetic fields when H≤80 kA/m under a pressure of 5 or 10 MPa and a “jump” effect occurs during the magnetization process. The dynamic strain coefficient, d33, dynamic incremental permeability,μ33, and magneto-mechanical coupling coefficient, k33, for the Tb0.3Dy0.7Fe2 rod polycrystal sample with <110> axial alignment were measured and discussed. The Tb0.27Dy0.73Fe2 polycrystals with <110> axial alignment possesses excellent magnetostrictive properties along the <110> rod direction in low magnetic fields and it is very useful in application of industry.
Study on the Shape Memory Behavior of Poly (L-Lactide)
Authors: Lu Xili , Cai Wei , Zhao Lian Cheng
Published: March 2009

Poly(L-lactide) (PLLA) was synthesized by the ring-opening polymerization of L-lactide and the shape memory behavior was studied using DSC and bending test experiments. The results indicate that the specimen shows the shape memory effect (SME), the small crystalline phase of PLLA and the mobility of amorphous phase may be responsible for the SME. The shape recovery of samples decreases and approaches to steady with the testing number increases.
Particle Size Reduction of Biomaterials Using Cryogenic Milling Process
Authors: Lee Sang Mok , Park Hoon Jae , Kim Seung Soo , Choi Tae Hoon , Kim E.Z. , Na Kyoung Hoan , Cho Hyun Kab , Rhee Kyong Yop
Published: March 2009

Reducing the particle size of drug materials down to submicron is an important matter in pharmaceutical industry. Cryogenic milling technology is one of the mechanical milling processes, which is mostly utilized in refining grain size of metal and ceramics at extremely low temperature environment. This technique has not been readily studied in application to medical and biotechnology. This paper, therefore, describes the application of cryogenic milling process to reduce particle size of Ibuprofen. The shape and size of the Ibuprofen particle before and after the cryogenic ball milling process were analyzed. XRD analysis was performed to examine a change in crystallinity of Ibuprofen by the cryogenic ball milling process. The results showed that the size of Ibuprofen particles was reduced to 1/10 or less of its initial size. The results also showed that the degree of crystallinity of Ibuprofen was slightly reduced after cryogenic ball milling with nitrogen.
Sound Absorption Properties of Fiber and Porous Materials
Authors: Hur Bo Young , Park Bu Keoun , Ha Dong-In , Um Yong Su
Published: March 2009

The porous materials, such as glass wool or foam, are generally used to attenuate noise. The most fundamental acoustic property of these porous materials is their sound absorption coefficient. The purpose of this paper is sintered fiber and porous materials sound absorption properties investigated. Sound absorption properties of sintered Al fiber has over 0.7 of sound absorption coefficient with 800-2000Hz frequency for 0.6 relative density and 10mm thickness. NRC (noise reduction coefficient) is 0.73. Metal foam have good sound absorption rate at 2000 ~ 4000Hz.
Effect of Alloying Elements on the Electronic Structure of NiAl
Authors: Yang Feng , Zhao Dong Liang
Published: March 2009

The change of the electronic structure in NiAl is investigated through DVM-the first
principle method when Al in NiAl is substituted by Sc,Ti,V, Cr, Mn, Fe, Co, Ni, Cu, Zn. The results including Mulliken population, the charge distribution and cohesion energies are presented. The calculation of the electronic structure indicates that the substitution atoms take effect on the electronic structure of Ni and Al atoms surrounding the substitution atoms, and the ductility of NiAl. Among the substitution atoms that we studied, Fe, Co and Ni with more d electrons may be good for the ductility of NiAl.
Numerical Simulation of Tube-Bending Process with Internal Pressure for Titanium Alloy Tube
Authors: Huang Xia , Zeng Yuan Song , Li Zhi Qiang , Zhang Xin Hua
Published: March 2009

In this paper, a new cold bending process is presented to form the titanium alloy tubular part with small relative bend radius, that is, its centerline bending radius is less than 2 times the outside diameter of the tube. FEM is applied to simulate the forming process, and at the same time the results, such as the distribution of the stress and the wall thickness, prediction of defects area, the effects of the internal pressure and friction condition on the tube deformation, are also analyzed.
Finally, experimental research was preformed. It is found that the numerical results are in good agreement with the experimental values.
Numerical Simulation and Experimental Evidence for Surface Modification by High Current Pulsed Electron Beam
Authors: Qin Ying , Dong Chuang , Wang Xiao Gang , Hao Sheng Zhi , Zou Jian Xin , Wu Ai Min , Liu Yue
Published: March 2009

The simulation of the temperature reveals an ultra high heating/cooling rates in the order of 108~109 K/s and melted layer thickness micrometers in depth. A temperature-induced dynamic thermal stress fields can then generate three principal stress, the quasi-static stress, the thermoelastic stress, and the shock stress, the latter two being stress waves. The thermoelastic stress wave has small amplitudes less than 0.1 MPa. The shock stress wave however is a typical nonlinear wave, several hundreds of MPa in amplitude, much stronger than the thermoelastic stress wave, and has a strong impact on materials structure and properties far beyond the heat-affected zone. The maximum compressive quasi-static stress in the surface layer in aluminum reaches several hundreds of MPa, which easily induces surface deformation in metallic materials.
A Simple Method of the Electric/Magnetic Field Observation by a Conventional Transmission Electron Microscope
Authors: Sasaki Katsuhiro , Saka Hiroyasu
Published: March 2009

A novel method to observe the electrostatic field distribution with a
conventional transmission electron microscope has been developed. The method allows measurements of a potential difference less than 1V/µm. This method can be performed in any kind of conventional transmission electron microscope and applied to the observation of the electric/magnetic field at the level of a specimen.
Observations of Carbon Nanotube Field Emission Failure in the Transmission Electron Microscope
Authors: Wang M.S. , Wang Jan Yong , Jin C.H. , Chen Qing , Peng Lian Mao
Published: March 2009

The failure of individual multiwall carbon nanotubes (CNTs) during electron field
emission was investigated in situ inside the transmission electron microscope (TEM). Long time emission of a single CNT at the level of tens µA or higher may lead to unrecoverable damage to the CNT. High-resolution TEM observations of the emission failure process shown that the failure was usually companied by structure damage or break of the CNT, and the failure or degradation of the emission characteristics of the CNT was typically initiated at the CNT/substrate contact, defect site or at the open end via the field evaporation or oxidation of the tip of the CNT.
Influence of Thermal Treatment on the Caustic SCC of Super Austenitic Stainless Steel
Authors: Yoo Y.R. , Chang H.Y. , Park Yong Bum , Park Y.S. , Chung Tai Joo , Kim Young Sik
Published: March 2009

In general, thermal treatment at 500oC ~ 900oC ranges depending upon alloy composition of stainless steels can sensitize the steels and promote the intergranular cracking, and their intergranular corrosion resistance is decreased. These behaviors seem to be related to the change of microstructures. So, heat treatment at that temperature range should be avoided in fabrication, especially welding of stainless steels. In this work, it is focused on the effect of thermal treatment on caustic stress corrosion cracking of super austenitic stainless steel - S32050 The low temperature thermal treatment increased greatly the resistance to caustic SCC than those of annealed specimen. This enhancement might be closely related to the reduction of residual stress and slightly large grain, but its resistance was not affected by the anodic polarization behavior.
Evaluation of Corrosivity in Atmospheric Environment by ACM (Atmospheric Corrosion Monitor) Type Corrosion Sensor
Authors: Shinohara Tadashi , Motoda Shin-ichi , Oshikawa Wataru
Published: March 2009

An ACM (Atmospheric Corrosion Monitor) type corrosion sensor, consisting of a Fe-Ag galvanic couple was developed and applied for the evaluation of corrosivity of atmospheric environments. The sensor was designed considering mass-production and good reproducibility of results, making it convenient for long-term corrosion data acquisition. Besides the sensor output, I, temperature, relative humidity (RH) were also recorded by a microcomputer. By analyzing the magnitude and time variation of I, the occurrence and duration of rain, dew and dry periods, Train, Tdew and Tdry, respectively, could be distinguished and determined. And by referencing to the empirical I-RH calibrating curve, the amount of deposited sea salt, Ws, could also be estimated. It was also found that the corrosion loss could be estimated in both indoor and outdoor sites by analyzing sensor output. Corrosivities of some kinds of exposure sites, not only outdoor environments but also indoor environments, were evaluated by using the ACM sensor.
The Effects of Partially Substituting Manganese with Copper in LiMn2O4 Cathodic Material
Authors: Kamarulzaman N. , Basirun Wan Jeffrey , Arof A.K.
Published: March 2009

Although LiMn2O4 is a very promising material for use as cathodes in lithium ion batteries, it exhibits capacity fading on cycling. Substituting some of the Mn with a 3d metal may improve the stability of the material. In this research, LiMn(2-x)CuxO4 (where x = 0.2 and 0.4) are synthesized and characterized by TGA, XRD and EDX. Cyclic voltammetry is also done to study their electrochemical characteristics. Results indicate improved thermal stability and some structural
change in the material. Cyclic voltammetry results show the redox potentials have been shifted from those obtained from pure LiMn2O4 material.
Dielectric Characterisation of Plastics for Microwave Oven Applications
Authors: Costa Luís Cadillon , Correia A. , Viegas A. , Sousa João Bessa , Henry François
Published: March 2009

The materials used in microwave oven cavities must have specific dielectric properties in order to maintain the efficiency of the food heating. Plastics, by their mechanical and chemical properties and low cost, are one of those potential materials. In this study, we present the results of the measurements of complex dielectric constant, ´´ ´ * e e e í − = , in the microwave frequency region, on different plastics: polyoxymethylene (POM), polypropylene (PP) and polybutylene terephtalate (PBT), using the cavity resonant method. We measure the shift in the resonant frequency of the cavity, Df, caused by the insertion of the sample,
which can be related to the real part of the complex permitivitty, e´, while the change in the inverse of the quality factor of the cavity, D(1/Q), gives the imaginary part, e´´. The relations are simple when we consider only the first order perturbation in the electric field caused by the sample.
The Atomic-Scale Interaction of Bioactive Glasses with Simulated Body Fluid
Authors: Skipper L.J. , Sowrey F.E. , Pickup D.M. , Newport R.J. , Drake K.O. , Lin Z.H. , Smith M.E. , Saravanapavan Priya , Hench Larry L.
Published: March 2009

The formation of a carbonate-containing hydroxyapatite, HCAp, layer on bioactive calcium silicate sol-gel glass of the formula (CaO)0.3(SiO2)0.7 has been studied in-vitro in Simulated Body Fluid (SBF). Extended X-ray Absorption Fine Structure (EXAFS), X-ray Absorption Near Edge Structure (XANES), X-ray diffraction (XRD), and solid state nuclear magnetic resonance (NMR) measurements have been performed with results showing the formation of a significantly amorphous HCAp layer after less than 5 hours in solution.