bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic Neutron Scattering from the Rare-Earth Intermetallic Compound System R3Pd20Si6 (R = Rare Earth)
Authors: Herrmannsdörfer Thilo , Dönni A. , Fischer P. , Keller L. , Janssen S. , Furrer Angela , van den Brandt B. , Kitazawa H.
Published: March 2009

The low-temperature magnetic properties of the rare-earth intermetallic compound
system R3Pd20Si6 (R = rare earth) were studied by elastic and inelastic neutron scattering. The compounds show due to the two rare-earth sublattices built from the 4a and 8c sites in the cubic crystal structure (space group Fm-3m) successive magnetic ordering with two different propagation vectors. In this report, we give an overview of the results obtained for the magnetic structures and the crystalline electric fields in the 3-20-6-system.
Order-Disorder Phase Transition in NaBD4
Authors: Fischer P. , Züttel Andreas
Published: March 2009

By means of neutron diffraction the low-temperature crystal structure of NaBD4 has been determined. At 10 K the lattice parameters are a = 4.332(1) Å and c = 5.869(1) Å. Deuterium is found in a tetrahedral arrangement [sites (8g)] around B. The symmetry corresponds to space group P42/nmc. For room temperature the structure model for NaBD4 of Davis and Kennard with disordered deuterium distributed over two sites has been revised to space group Fm-3 m. Thus the 190 K phase transition known from specific heat measurements is of order-disorder type, caused by reorientations of BD4 tetrahedra.
Kinetical Investigations on Lamellar CalciumAluminateChromateHydrates with High Speed Detector
Authors: Göske J. , König U. , Pöllmann Herbert
Published: March 2009

Lamellar calciumaluminatehydrates are products of the hydration of ordinary Portland
cement and play an important role in its hardening process. Due to the fixation ability of inorganic ions the technical features of this lamellar phases are important as reservoir minerals for pollutants (storage minerals). The lamellar calciumaluminatechromatehydrate Monochromate with the idealized formula C3A.Al2O3.CaCrO4.Ca(OH)2.nH2O has been investigated using a Philips
Diffraction System X'Pert with the X'Celerator detector to measure the kinetics of the changes in interlayer dimensions in the lamellar calciumaluminatechromatehydrate at room temperature in air. A certain amount of water is weakly fixed in the interlayer depending on the interlayer anion, temperature and relative humidity of the atmosphere. Processes like ion exchange or water-loss in the interlayer cause a variation of the crystal dimension in c-direction. These "processes" can be very fast, therefore an ultra fast data collection and measurement times less than 2 minutes from 2° 2Θ to 70° 2Θ were essential.
Synthesis and Crystal Structure of the Double Perovskite Ca2-xSrxMnWO6  (x = 0.0, 0.5, 1.0, 1.5, 2.0)
Authors: Azad A.K. , Eriksson S.-G. , Rundlöf Håkan , Eriksen J.
Published: March 2009

The double perovskites Ca2-xSrxMnWO6 (x = 0.0, 0.5, 1.0, 1.5, 2.0) have been prepared as pure phases by a conventional solid-state reaction process. Stoichiometric amounts of CaCO3,SrCO3, MnO and WO3 were mixed, ground and calcined in a nitrogen atmosphere. X-ray and neutron powder diffraction (NPD), together with magnetisation measurements were carried out in order to characterise the materials. The NPD and magnetisation measurements, performed at
different temperatures, were made in order to correlate the materials structural and magnetic properties. Susceptibility- Temperature (ϰ-T) curves were measured between 2K and 200K in field cooled (FC) and zero-field-cooled (ZFC) modes with an applied field (H) up to 3T. Rietveld analysis of NPD data shows that the samples were B-site ordered perovskites with different types of lattice symmetry. Magnetisation measurements at low temperatures indicate an antiferromagnetic
ordering of the magnetic moments.
Presence of a Spin Glass State in Antiferromagnetic Tb2CuIn3
Authors: Siouris I.M. , Semitelou I.P. , Yakinthos J.K. , Schäfer Wolfgang
Published: March 2009

Evidence of the coexistence of an ordered antiferromagnetic and a spin glass state is given by studying a polycrystalline Tb2CuIn3 sample with neutron diffraction in a non-magnetic and a magnetic environment. Tb2CuIn3 is an antiferromagnet with competing exchange interactions (J1> 0 for nearest neighbours and J2 < 0 for next nearest neighbours) and an ordering temperature TN =33 ± 1 K. Powder diffraction measurements reveal a broad diffuse peak - due to short-range
magnetic order - underneath the (100) long-range order magnetic Bragg reflection. The exposure of the sample in magnetic fields up to 7.5 T, under both zero field and field-cooled conditions, show that neither the long-range magnetic order nor the short-range order are destroyed by the outer magnetic fields. The almost field independent behaviour of the magnetic intensities is explained by
the existence of a spin glass state. Support on the simultaneous presence of antiferromagnetic and spin glass states is given by recent ac-dc magnetic measurements. The infinite range model for spin glasses with strong uniaxial anisotropy has predicted this kind of magnetic behaviour.
Thermal Expansion and Excess Properties of Åkermanite-Gehlenite Synthetic Solid Solution Series
Authors: Proverbio Marco , Dapiaggi Monica , Artioli Gilberto
Published: March 2009

Thermal expansion of some members of the synthetic solid solution åkermanite-gehlenite was measured (in the range 25-1200°C) for the very first time, with the aim of clarifying the behaviour of this solid solution both with respect to composition and temperature. The results confirmed the non-ideal behaviour at room temperature (negative excess molar volume), and showed a different non-ideal response at high temperature. In fact, excess molar volume is different during the heating and cooling stages: for Xak<0.5 it becomes, from almost ideal, strongly positive at high temperature, while for Xak>0.5 it is always negative. It can then be inferred that (i) lattice dimensions are very sensitive to cation diffusion activated by temperature, (ii) intra-crystalline partition mechanisms, and their effects on the structural features, vary as a function of composition in the solid solution studied.
XRD Study of the Nacrite/CsCl/H2O Intercalation Complex
Authors: Naamen S. , Ben Rhaiem H. , Ben Haj Amara A.
Published: March 2009

The intercalation complex of nacrite with an alkali halide (Caesium chloride: CsCl) has been successfully prepared by mixing a CsCl saturated solution with a 8.4Å-hydrated nacrite. The homogeneous nacrite/CsCl complex has been studied by X-ray diffraction (XRD). Using an oriented clay aggregate, 10 basal reflections were obtained. The XRD pattern showed basal
spacing of 10.5Å with integral series of 00l reflections indicating an ordered stacking of parallel 1:1 layers. A direct method involving a monodimensional electron density projection, along the normal to the layers, is used to determine the number and the position of intercalated compounds. The best agreement between observed and simulated p(Z) (R = 5%) is obtained by placing one Cl-
ion at Z=6.7Å; one Cs+ ion at Z=8.3Å and two H O molecules at 6.3 and 7.4Å.
Simulation of X-Ray Powder Diffraction Patterns for One-Dimensionally Disordered Crystals
Authors: Cherepanova S.V. , Tsybulya S.V.
Published: March 2009

Software for the simulation of X-ray powder diffraction (XRPD) patterns for ultrafine-grained materials with some kinds of imperfections has been developed. These calculations are performed on the base of the model of one-dimensionally disordered (1D-disordered) crystal [1]. Such a model can describe stacking faults (SF) and other planar defects (PD) and also finite size of coherently scattering domains. Simulated XRPD pattern is compared with experimental one and can be fitted to it. Potentialities of the software are illustrated by several examples.
Sintering Behavior of the Powder Injection Molded Nanocrystalline Fe-50wt%Ni
Authors: Nam H.Y. , Kwon S.K. , Kang Young Soo , Lee Jai Sung
Published: March 2009

Sintering process of powder injection molded (PIMed) Fe-50wt%Ni nanoalloyed powder
was investigated in association with microstructure development and residual impurity effect.
Compared to conventional powder metallurgical (PM) processed Fe-Ni nanoalloy powder, the PIM
compact showed a homogeneous and uniform densification behavior. This is owing to more
homogeneous particle distribution in the PIM resulting from preparation of feedstock which was
fabricated by mixing of nano powder with thermoplastic binder. Residual impurities originating from
the binder material did not have any apparent influences on sintering behavior. Conclusively,
Fe-50wt%Ni nanoalloy powder is effectively applicable to the PIM parts.
Effects of Processing Variables on the Development of the Cube Texture in Ni Tapes Fabricated by the Cold Working of Ni Powder Compact Rods
Authors: Ji Bong Ki , Lim Jun Hyung , Lee Dong Wook , Kim Min Woo , Jun Byung Hyuk , Kim Chan Joong , Joo Jin Ho
Published: March 2009

We studied the effects of the processing variables on the texture development of Ni tapes prepared from Ni powder compact rods. The Ni power was compacted into rods by cold isostatic pressing(CIP). The CIP-processed Ni rods were sintered for densification and made into Ni tapes of 100 microns by cold rolling. For the development of a cube texture, the rolled Ni tapes were annealed at various temperatures. The brass texture was converted into a cube texture during annealing and the degree of the formed cube textured was dependent on the annealing temperature. We analyzed the (200) cube texture by X-ray diffraction and pole figure analysis and EBSD(Electron beam backscattered diffraction pattern).
Effect of Heating Rate on Transient Liquid Phase Diffusion Bonding of Ni-Based Superalloy GTD-111
Authors: Choi Woo Hyuk , Kim Sung Wook , Lee Chang Hee , Jang Jung Cheol
Published: March 2009

This study was carried out to investigate the effect of heating rate on dissolution and
solidification behavior during transient liquid phase diffusion bonding of Ni-based superalloy GTD-111. The heating rate was varied by 0.1K/sec, 1K/sec, 10K/sec to the bonding temperatures 1373K and 1423K in vacuum. When the heating rate was slower and the bonding temperature was higher, the completion time of dissolution after reaching bonding temperature decreased. When the heating rate was very slow, the solidification proceeded before reaching bonding temperature and the
time required for the completion of isothermal solidification was shorter. However, when the total time required for completion of solidification from the beginning of heating was considered, heating at 0.1K/sec was nearly the same as heating at 10K/sec.
Recovery of Lithium from Seawater Using Nano-Manganese Oxide Adsorbents Prepared by Gel Process
Authors: Chung Kang Sup , Lee Jae Chun , Kim Eun Jin , Lee Kyung Chul , Kim Yang Soo , Ooi Kenta
Published: March 2009

Adsorbing and salvaging extremely small quantities of lithium ion, high-performance
ion-exchange type lithium ion adsorbent was prepared through the ion-sieve formation method. The method uses acid treatment after the synthesis of spinel-structured nano-Li1.33Mn1.67O4 precursor through the tartaric acid gel process. It has good selectivity and high efficiency in adsorbing lithium ion in seawater. The generated adsorbent showed a 28.2 mg/g lithium uptake from artificial seawater. This adsorbent further showed a difference reproducibility that was lower than 10% when subjected to five cycles of adsorption and desorption experiments.
Fabrication of Al2O3-ZrO2 (3Y-TZP) Composites with Graded Structures by Centrifugal Slip Casting Method
Authors: Li X.D. , Wang Larry , Onda Tetsuhiko , Akao T. , Hayakawa Motozo
Published: March 2009

Centrifugal casting method was used to fabricate composites with graded structures in alumina-zirconia system. The composition profiles of the graded composites showed three distinct regions, with a greater part of the specimen showing nearly linear variation of compositions. The composition profile can be varied by using zirconia powder of different size ranges. The top of the specimens showed nano-scaled microstructures. The composition profiles can also be varied by altering zirconia content in the starting suspension. It was found that the composites with graded structures showed higher bending strength than that of uniform composites. On the other hand, the specimens fractured with the lower zirconia content region being the crack initiate plane showed higher bending strength than that of fractured form higher zirconia content region.
Recent Progress in Molecular Orbital Approach to Alloy Design
Authors: Morinaga Masahiko , Yukawa Hiroshi
Published: March 2009

A molecular orbital approach to alloy design has recently made great progress. This approach is based on the electronic structure calculations by the DV-Xα molecular orbital method. New PHACOMP and the d-electrons concept have been constructed and applied to alloy design. Recently, nickel-based single crystal superalloys for power generation gas turbine blades and high Cr ferritic steels for turbine rotors have been developed successfully with this approach.
Welding of Aluminum and Steel by Friction Stir Diffusion Process
Authors: Yasui Toshiaki , Shimoda Youichirou , Tsubaki Masami , Fukumoto Masahiro
Published: March 2009

Welding between ADC12 and SS400 was successfully performed by friction stir diffusion process. The experiments were conducted by a machining center with a cemented carbide tool and welding conditions, such as a rotating speed, welding speed and position of the tool, were optimized. By plunging the rotating tool into the interface with offset, ADC12 and SS400 were welded above 2000 rpm of the rotating speed at the welding speed of 50mm/min. Tensile strength was evaluated for the welded specimens. The specimens fabricated above 5000rpm in the rotating speed were fractured at the weld zone and showed relatively low tensile strength. The specimens, on the other hand, made between 2000 and 4000 rpm were fractured in the portion of the base aluminum alloy. Achievement of more than 100% in joint efficiency was indicated in the present friction stirring process.
Thermoelectric Properties of the Pseudogap Fe2VAl System
Authors: Nishino Yoichi
Published: March 2009

While the Heusler-type Fe2VAl compound exhibits a semiconductor-like behavior in
electrical resistivity, doping of quaternary elements causes a sharp decrease in the low-temperature resistivity ρ and a large enhancement in the Seebeck coefficient S. Substantial enhancement in S can be explained on the basis of the electronic structure where the Fermi level shifts slightly from the center of a pseudogap either up- or downward depending on doping. In particular, a slight substitution of Si for Al leads to a large power factor (P = S2/ρ) of 5.5×10-3 W/m K2 at around room temperature.
Towards SiGe Terahertz VCSELs
Authors: Kelsall R.W. , Ikonić Z. , Harrison P. , Paul D.J. , Lynch S.A. , Bates R. , Norris D.J. , Liew S.L. , Cullis A.G. , Arnone D.D. , Pidgeon C.R. , Murzyn P. , Robbins D.J. , Soref R.A.
Published: March 2009

Asymmetric rolling, in which the circumferential velocities of the upper and lower rolls are different, can give rise to intense plastic shear strains and in turn shear deformation textures through the sheet thickness. The ideal shear deformation texture of fcc metals can be approximated by the <111> // ND and {001}<110> orientations, among which the former improves the deep drawability. The ideal shear deformation texture for bcc metals can be approximated by the Goss {110}<001> and {112}<111> orientations, among which the former improves the magnetic permeability along the <100> directions and is the prime orientation in grain oriented silicon steels. The intense shear strains can result in the grain refinement and hence improve echanical properties. Steel sheets, especially ferritic stainless steel sheets, and luminum alloy sheets may exhibit an undesirable surface roughening known as ridging or roping, when elongated along RD and TD, respectively. The ridging or roping is caused by differently oriented colonies, which are resulted from the <100> oriented columnar structure in ingots or billets, especially for ferritic stainless steels, that is not easily destroyed by the conventional rolling. The breakdown of columnar structure and the grain refinement can be achieved by asymmetric rolling, resulting in a decrease in the ridging problem.
The Correlation Theory of 2D Normal Grain Growth
Authors: Nordbakke M.W. , Ryum N. , Hunderi Ola
Published: March 2009

Computer simulations of 2D normal grain growth have shown that size correlations between adjacent grains exist in 2D grain structures. These correlations prevail during the coarsening process and influence on the kinetics of the process and on the grain size distribution. Hillert’s analysis starts with the assumption that all grains in the structure have the same environment. Since computer simulations contradict this assumption, the mean-field theory for normal grain growth needs to be modified. A first attempt was made by Hunderi and Ryum, who modified Hillert’s growth law to include the effect of spatial grain size correlations. In the 1D case the distributions derived by means of the modified growth law agreed well with simulation data. However, the distribution derived for 2D grain growth retained unwanted properties of the Hillert distribution. We review some recent progress in developing a mean-field statistical theory. A paradox related to curvilinear polygons is shown to support the expectation that the grain size distribution has a finite cutoff.
Recrystallization in 304 Austenitic Stainless Steel
Authors: Dehghan-Manshadi A. , Beladi Hossein , Barnett Matthew R. , Hodgson Peter D.
Published: March 2009

A 304 austenitic stainless steel was deformed using hot torsion to study the evolution of dynamic recrystallization (DRX). The initial nucleation of dynamically recrystallization occurred by the bulging of pre-existing high angle grain boundaries at a strain much lower than the peak strain. At the peak stress, only a low fraction of the prior grain boundaries were covered with new DRX grains. Beyond the peak stress, new DRX grains formed layers near the initial DRX and a necklace structure was developed. Several different mechanisms appeared to be operative in the formation of new high angle boundaries and grains. The recrystallization behaviour after deformation showed a classic transition from strain dependent to strain independent softening. This occurred at a strain beyond the peak, where the fraction of dynamic recrystallization was only 50%.
Grain Growth and Texture Evolution during Annealing of Submicrocrystalline Titanium Produced by Severe Plastic Deformation
Authors: Malysheva Svetlana , Salishchev Gennady A. , Mironov S.Yu. , Betsofen Sergei Ya.
Published: March 2009

The paper considers the structure evolution during annealing of submicrocrystalline (SMC) titanium with a mean grain size of 0.2 µm, processed by severe plastic “abc” deformation. Electron microscopic studies have revealed that the microstructure of the SMC titanium is heterogeneous and of a mixed type. One can observe a high density of dislocations, grains, subgrains, elements of a banded structure and areas comprising coarse (up to 1-2µm) and fine (up to 0.1µm) grains. The grain boundary misorientation spectrum is presented by low angle and high angle boundaries of random and special types. Three stages of annealing of SMC titanium have been revealed. The second stage is connected with the intense SMC grain growth and the value of activation energy of grain growth at this stage is twice less than the value of activation energy of grain boundary diffusion in titanium. The latter is caused by acceleration of diffusion processes at SMC grain boundaries having an atom-disordered structure. The texture evolution with annealing temperature is characterized by weakening of predominantly basal texture in the as-received SMC state and strengthening of a prismatic component. The weakening of the basal component is connected with the growth of SMC grains first of all, as well as the increase of the volume fraction of special boundaries.
Laser-Ultrasonics as a Technique to Study Recrystallisation and Grain Growth
Authors: Lindh-Ulmgren Eva , Ericsson Mattias , Artymowicz Dorota , Hutchinson W. Bevis
Published: March 2009

Laser-Ultrasonics (LUS) provides a means of obtaining microstructure information continuously and non-destructively both in the laboratory and for quality control on-line in industry. Ultrasound is both generated and recorded using lasers which permits remote, non-contact operation with fast sampling and also the capability of working at high temperatures or at moving surfaces, for example during industrial continuous annealing. Examples of dynamic heating trials will be presented for samples of cold rolled steel sheets where primary recrystallisation and ferrite austenite transformation are monitored in-situ as a function of temperature. Examples are also presented where the grain size of low carbon steels have been quantitatively analysed and show very good agreement with microscopy methods.
Recrystallization Nucleation in Some Channel Die Deformed, High Symmetry Aluminium Bicrystals
Authors: Paul Henryk , Driver Julian H.
Published: March 2009

The crystallography of recrystallization nucleation in high purity aluminium bicrystals,
with boundary planes situated parallel to the compression plane, has been characterized in detail by microtexture analyses. The experiments were carried out on samples with 2 types of bicrystal orientations composed of the stable Goss{110}<001> with an unstable cube{100}<001> or shear{100}<011> orientation. The bicrystals were cold deformed in channel-die compression up to
true strains of 1.5. During recrystallization annealing, the deformation bands of the unstable orientations are the privileged sites for the formation of new grains. These nuclei were misoriented with respect to the orientations identified within the neighbouring deformed areas by α(<111>, <112> or <100>) relations. Growth of the new grains is always favoured along directions parallel to the traces of the {111} slip planes as shown in the stable and structurally homogeneous Goss
{110}<001> oriented grains. The grain boundary can play a role in recrystallization similar to that of the deformation bands.
Effect of Solution Heat Treatment and Additives on the Microstructure of Al – Si (A413.1) Automotive Alloys
Authors: Moustafa M.A. , Samuel F.H. , Doty H.W.
Published: March 2009

A study was carried out to determine the role of additives such as Mg and Cu on the microstructural characteristics of grain refined, Sr-modified eutectic A413.1 alloy (Al-11.7% Si) during solution heat treatment. For comparison purposes, some of the alloys were also studied in the non-modified condition. The alloys were cast in a steel permanent mold preheated at 425 °C that provided a microstructure with an average dendrite arm spacing (DAS) of ~ 22 µm. Castings were solution heat treated at 500 ± 2 °C for time up 24 h, followed by quenching in warm water (at 60 °C). Microstructural analysis of the as-cast and heat-treated castings was carried out using optical microscopy in conjunction with image analysis. Phase identifications were done using the electron probe microanalysis (EPMA) technique. In the as-cast condition, the addition of 0.42 wt% Mg to the unmodified alloy produced relatively large Si particles compared to the base A413.1 alloy. The Si particle size remained more or less the same with increase in solution treatment time and Mg level. Both Mg2Si and Al2Cu phases were observed to dissolve almost completely after 8 h solution time, while the Al5Cu2Mg8Si6 phase was found to persist even after 24 h.
New Grain Formation in a Coarse-Grained 7475 Al Alloy during Severe Hot Forging
Authors: Sitdikov Oleg , Sakai Tetsuo , Goloborodko Alexandre , Miura Hiromi , Kaibyshev Rustam
Published: March 2009

Strain-induced grain refinement in a coarse-grained 7475Al alloy was studied by means of multidirectional forging (MDF) carried out at T = 490oC under a strain rate of 3 x 10-4 s-1. Integrated flow curves exhibit significant work softening just after yielding, followed by steady-state-like behavior at high strains. The evolution of new fine grain structure during deformation can be assisted by grain-boundary sliding, resulting in frequent formation of high strain gradients and subsequently microshear bands in grain interiors. Microshear bands developed in various directions are intersected with each other, subdividing original grains into misoriented small domains. The number and the misorientation angle of microshear bands progressively increase during deformation, finally followed by their transformation into high-angle boundaries. It is concluded that grain refinement under hot MDF conditions occurs by a series of deformation-induced continuous reactions; that is essentially similar to continuous dynamic recrystallization.
The Recrystallization Behaviour of CP-Titanium
Authors: Güçlü F.M. , Çimenoğlu H.
Published: March 2009

In the present investigation, recrystallization of Grade-2 quality commercial purity titanium (CP-Ti) has been studied. CP-Ti was received as 4 mm thick plate having hardness of 202 HV0.3. Upon rolling about 55, 70 and 85 % at room temperature, the hardness increased to 268, 276 and 283 HV0.3, respectively. Cold rolled samples were then subjected to isothermal annealing in salt bath at 550-700°C. After measuring hardness, recrystallization curves were plotted for each annealing temperature. Recovery region was not clearly visible on the recrystallization curves. Heavily cold worked samples were soften rapidly and reached to the grain growth region at shorter annealing times. According to Arrhenius plot, recrystallization activation energy of CP-Ti was calculated in between 89,5 and 78,6 kJ/mol. The higher the cold working, the lower is the recrystallization activation energy.
A Subgrain Growth Model for Strain-Free Grain Nucleation during Recrystallization
Authors: Holm Elizabeth A. , Miodownik Mark A. , Healey Kristopher J.
Published: March 2009

The origin of the strain-free crystallites that nucleate the recrystallization process has been debated for decades. Realistic, three-dimensional computer simulations indicate that the nucleation event is the mobility-driven abnormal growth of certain subgrains. Based on these observations, we derive a model that incorporates subgrain topology, texture, boundary distribution and boundary properties to predict the frequency of the abnormal growth events that lead to nucleation. The qualitative and quantitative agreement between theory, simulation, and experiments is excellent.
Numerical Experiments into the Localization of Deformation during Recrystallization Flow
Authors: Jessell M.W. , Bons P.D. , Evans L. , Piazolo Sandra
Published: March 2009

The localization of deformation in recrystallizing materials is investigated via a series of two-dimensional grain-scale numerical simulations. These simulations couple a grain size and strain dependant viscous rheology with grain size reduction and grain growth processes. The simulations are able to predict the mechanical, microstructural and strain evolution of the polycrystals to high strain, and allow us to examine the nature of the time dependent feedback between mechanical and
microstructural behavior. It was found that significant strain localization occurred only when the grain size dependence of the viscosity was non-linear, and was greatly enhanced by the activity of the grain size modifying processes. The intensity and location of the zone of strain localization varied spatially and temporally, with the result that the finite strain state showed a much broader, and hence less intense, zone of localized deformation than the instantaneous state.
Effects of Overall Grain Boundary Nature on Localized Corrosion in Austenitic Stainless Steels
Authors: Wasnik D.N. , Kain Vivekanand , Samajdar I. , Verlinden Bert , De P.K.
Published: March 2009

Thermo-mechanical processing of type 304 and type 316L stainless steels done by (a) cold rolling to a reduction in thickness of 20 to 80 percent and (b) solution annealing to obtain a medium size of grains led to a considerable improvement in resistance to both sensitization and intergranular corrosion. The nature of the resultant grain boundaries was examined in a scanning electron microscope using orientation imaging microscopy in electron back scattered diffraction mode. Fraction of random and special grain boundaries were established for each set of thermo-mechanical processing. After appropriate sensitization treatments, the degrees of sensitization of these stainless steels were evaluated by double loop electrochemical potentiokinetic reactivation tests. Standard ASTM tests were used to evaluate susceptibility to intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGSCC). These studies showed that a particular combination of thermomechanical processing led to formation of over 75 percent random grain boundaries in the steels and this imparted resistance to sensitization and to IGC and IGSCC. This opens a new concept in grain boundary (GB) engineering of a high fraction of random GB increasing the resistance to localized corrosion like IGC and IGSCC. Textural studies were carried out with the help of X-ray and MTM-FHM software. It showed significant change of texture in type 304 stainless steel, while no change in the texture of type 316L stainless steel after cold rolling and annealing.
Role of Silicon Content and Final Annealing Temperature on Microtexture and Microstructure Development in Non-Oriented Silicon Iron
Authors: Hu Yan , Randle Valerie , Irons Terry
Published: March 2009

A matrix of twelve laboratory heat treated iron-silicon specimens were investigated to
identify the microtextures, grain misorientations and grain size distributions present and to relate them to the various silicon contents and annealing cycles. The steel grades examined contained either 1.0%, 2.4% or 3.0% silicon. The results showed that the higher strain levels present in the hot rolled microstructures as silicon content increased created a greater driving force for recovery, recrystallisation and grain growth processes.
Study on the Effect of Tool Rake Angle on Cutting Vibration in Precision Machining
Authors: Wang Gui Cheng , Ma Li Jie , Pei Hong Jie
Published: March 2009

The cutting vibration is one of the main factors to affect precision machining. In this
paper, the influence of tool rake angle on cutting vibration is studied at different cutting speed in turning operation, and corresponding theoretical analysis is made. The experiment results show that: the amplitude of machining vibration gradually decreases with tool rake angle increasing; while rake angle o g <0°, the biggest amplitude occurs at V=50~70m/min; While o g ≥0°, it is at V=160~180m/min. Moreover, theory and experiment foundation is presented on avoiding the biggest amplitude range so as to guarantee quality of precision machining at high speed.
Study on the Micro-Topography and Texture Characteristic of Machined Surface in High Speed Turning for Carbon Steel
Authors: Ye Bang Yan , Xu Jin , Liu Xiao Chu , Quan Yan Ming
Published: March 2009

In this article, the micro-topography and texture characteristics of machined surface under the condition of high speed cutting are analyzed based on experimental observation. The forming process of machined surface and cause of the appearance are also discussed. The experimental results show that furrow and ridges, surface white layer and molten metal daub by the feed motion of cutting tool are found on machined surface due to the effect of high cutting temperature and rotating of workpiece in high speed turning process.
Effect of TiN Addition on Microstructure and Mechanical Properties of Zirconia Matrix Ceramic Tool Material
Authors: Sun Jing , Huang Chuan Zhen , Liu Han Lian , Wang Sui Lian
Published: March 2009

In this paper, 3mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) and
TiN/3Y-TZP(adding TiN particles to 3Y-TZP) composites were fabricated by hot-pressing technique. Phase composition, microstructure and mechanical properties of the composites were investigated. It is shown that the flexural strength, fracture toughness and Vickers hardness of TiN/3Y-TZP was significantly improved by the addition of TiN particles compared with 3Y-TZP. The flexural strength of ZYT2 (20wt% TiN addition) is 1318 MPa. The fracture toughness of ZYT4 (40wt% TiN addition) is 16.8MPa·m1/2. The toughening and strengthening mechanisms were analyzed. The XRD results show that the additing of TiN can hinder the transformation from tetragonal phase to monoclinic phase of 3Y-TZP during fabrication process.
Solutions for Interpreting STEP-NC Based Part Program
Authors: Liu Ri Liang , Zhang Cheng Rui
Published: March 2009

STEP-NC is a new CNC data interface proposed to replace ISO 6983, and has been partly formed into the draft international standard (ISO 14649). In this paper, the STEP-NC-based part program is analyzed, and the general methodology and tools for STEP-compliant application development are introduced. Then a framework for STEP-NC interpreter is proposed based on the SDAI method and the implementation solutions are presented. The EXPRESS compiler is used to convert the milling schema into C++ classes, and the information is extracted from the file in aid of data access tools. The said interpreter, which is fundamental to STEP-NC based machining, is also implemented with supporting tools in the ST-Developer environments. It is used to read the STEP-NC file into ROSE working form, and then extract and organize the manufacturing information in an object-oriented way.
A Study on the Mechanical Properties of Ti(C, N) Based Ceramic Tool Material
Authors: Wang Sui Lian , Xu Li Qiang , Huang Chuan Zhen , Liu Han Lian
Published: March 2009

Ti(C, N) based ceramic tool materials in the Ti (C0.7N0.3)-(Ni-Co)-Cr3C2-VC system have been made by hot-pressing technology, their mechanical properties and fracture morphologies have been studied under three different fabrication conditions. The results show that the mechanical properties are significantly influenced by fabrication conditions, and the main fracture mode is intergranular fracture.
Research on Multifunctional Micro Machining Equipment
Authors: Jia B.X. , Wang Zhen Long , Hu Fu Qiang , Li Xiao Hai , Zhao Wan Sheng
Published: March 2009

To perform several micro-machining on same machine tool, a micro machining
equipment was researched and developed. The equipment adopts some high and new technologies. It is equipped with high precision XYZ stage, a spindle with high rotation accuracy and variable rotation speed, a granite worktable, a block electro discharge grinding unit for machining micro rod, a ultrasonic vibration unit for workpiece vibrating, a high frequency pulse power supply for micro-ECM and a video microscopic system with high enlargement factor. The equipment can
perform micro electro discharge machining (EDM), micro electrochemical machining (ECM), micro ultrasonic machining (USM) as well as their combination. It can also machine 3D microstructures. A series of experiments were carried out. Using micro-EDM, micro rods with the diameter of less than 5µm were ground on block electrode, micro holes and 3D microstructures were obtained. Shaped holes were machined by using combination of micro-EDM and micro-USM.
A micro hole with the diameter of 100µm was machined via micro-ECM.
Balancing of Tool/Toolholder Assembly for High-Speed Machining
Authors: Zhang Song , Ai Xing , Tang Wei Xiao , Liu J.G.
Published: March 2009

High-speed machining has become mainstream in machining manufacturing industry. In industries such as moldmaking and aerospace, it has become the norm rather the exception. The centrifugal force increases as the square of the speed. At rotational spindle speeds of 6,000 r/min and higher however, centrifugal force from unbalance becomes a damaging factor and it reduces the life of the spindle and the tool, as well as diminishes the quality of the finished product. Under high rotational speed, good balance becomes issue. High-speed machining experimental results shown that a well-balanced tool/toolholder assembly could obviously improve machining quality, extend tool life and shorten downtime for spindle system maintenance etc.
An Investigation on High Strain Rate Superplasticity of an Al-Cu-Mg-Ti-Sr Ingot Alloy
Authors: Xu Xiao Jing , Cai Lan , Kim Seock Sam
Published: March 2009

An ingot aluminum alloy (Al-Cu-Mg-Ti-Sr) with high strength and high strain rate
superplasticity has been successfully developed through a conventional manufacture route consisting of casting, heat treatment, hot extrusion with a low extrusion rate of only 10:1, hot-rolling and further cold-rolling, which is cost effective and suitable for large volume production industries. The tensile test result showed the alloy possesses not only a high ultimate strength of 513.85MPa at room temperature, but also a good high strain rate superplasticity with the tensile elongation of 174~224%, the flow stress of 17.1~33.9MPa and the strain rate sensitivity m-value of 0.174~0.293 in the initial strain rate of 3.16×10-2~1.0×10-1s-1 and at the temperature of 748K~793K. Differential scanning calorimeter (DSC) analysis showed that the superplastic deformation has no relationship with liquid phase. Scanning electron microscopy (SEM) analysis of fracture surface and surface showed that the superplastic deformation results from fine grain boundary sliding and dislocation slip.
Rough Set Data Analysis System and Its Applications in Machinery Fault Diagnosis
Authors: Hao L.N. , Chen Wen Lin , Zhang X.F. , Wang Wan Shan
Published: March 2009

The characteristics of fault diagnosis are as follows. First, features extraction is the key of improving diagnosis efficiency and correct rate. Secondly, fault diagnosis method based on rule reasoning has a wide application, but rule acquisition is one of the bottlenecks. Thirdly, rule modification is a key question of solving the real-time rule acquisition in the dynamic environments, and a primary question of knowledge base modification of expert system, etc. In this paper, Rough Set Theory (RST) was used to solve the key problems of machinery fault diagnosis, and a Rough Set Data Analysis System (RSDAS) was developed. RSDAS was used to implement rule generation automation & rule modification based on RST such as indiscernibility relation and knowledge reduction method, depicted importance of different attributes in knowledge representation, and reduced knowledge representation space. The method of fault diagnosis using RSDAS was summarized. The experiment results approved the feasibility and the high precision of RSDAS. Therefore, we can use RADAS to machinery fault diagnosis.
A Hybrid Model for Tool Condition Monitoring and Optimal Tool Management
Authors: Yao Ying Xue , Lu Y. , Yuan Zhe Jun , Hu J.Y.
Published: March 2009

This paper introduces a new hybrid model for tool condition monitoring (TCM) and
optimal tool management (OTM) in end milling operation. The model includes a wavelet fuzzy neural network with acoustic emission (AE) and a model of fuzzy classification of tool wear state with the detected cutting parameters supported by cutting database. The results estimated by cutting conditions and detected signals are fused by artificial neural network (ANN) so as to facilitate effective tool
replacement at a proper state or time. The validity and reliability of the method are verified by experimental results.
Minimum Lubrication Milling of Titanium Alloys
Authors: Hassan A. , Yao Zheng Qiang
Published: March 2009

During excessive fluid application processing, fluid ends up on the floor, the workers, and the machine, entail serious techno-environmental and biological problems. Very little fluid enters the tool/part interface. Recently, this excess fluid has become another costly control problem. Chemicals of all types introduced into the atmosphere must also be reduced to an absolute minimum. In this paper, the technique of minimum quantity of lubrication (MQL), which is the pulverization of a minimum volume of oil in a flow of compressed air, has been studied in face mill Ti-6Al-4V titanium alloys as one alternative to the use of abundant cooling to suppress the cutting heat resulted from low thermal conductivity and the density of the workpiece material. The results showed that MQL of 125ml/h flow amount was found to be the optimum, and there is no significant difference in temperature between MQL of this flow and wet cooling when low cutting speeds used.
Tribological Investigations of Parts Sintered and Coated by Laser Beam
Authors: Sebestyén T. , Buza Gábor , Franek F. , Takács János , Kálazi Zoltán , Pauschitz A. , Tóth László S.
Published: March 2009

In this work we intend to investigate the surface properties of laser sintered and coated parts, by measurement of friction coefficient and wear rate. The main aim of this research is to justify laser sintered prototype tools for injection molding of fibre-reinforced polymers. For increase of wear resistance we used hard Co-based and Fe-based coatings on laser-sintered phosphorous bronze and unalloyed steel substrate. Short carbon- and glass-fibre-reinforced polymers were used as counter bodies. For the tribological laboratory model tests a pin-on-disk test rig was used. In case of coated parts – with higher wear resistance – we used a cylinder-on-cylinder tribometer. The tribological properties were determined at different load conditions. Our results show that the friction coefficient and wear resistance of laser treated surfaces are good. The coefficient of friction of coated specimens is slightly less, but the wear rate is significantly less.
Macrostructure Prediction of CC Slabs
Authors: Réger Mihály , Verő Balázs , Kytönen Heli , Louhenkilpi Seppo , Szélig Árpád
Published: March 2009

The inner structure of the continuously cast semis has a great importance from the point of view of further processing and application. The main reason for this is the very direct effect of the inner structure’s features (ie. porosity, macrosegregations, geometry of primary dendrites) on the technological characteristic features of the semis during further processing (ie. crack sensitivity,
formability, etc.). The paper deals with the possible ways of macrostructure determination on the basis of the results of mathematical modeling of continuous casting process. We pay a special attention to the columnar-equiaxed transition as a function of heat parameters of the casting process and to the macrosegregation formation caused by the motion of solute enriched interdendritic liquid in the mushy zone.
Influence of Tin-Chloride Pretreatment on Mirror Coating Adhesion
Authors: Nagy A. , Hegman Norbert
Published: March 2009

Our research focused on the adhesion properties of mirror coating on silica float glass due to applying different quantity of tin-chloride sensitizing agent. Investigation was carried out to detect the distribution and quantity of tin containing clusters deposited on the glass surface working as crystallization centre. The adhesion properties of coatings were tested by scratch test where critical peeling forces were evaluated. The morphology of the formed scratch track was measured with
scanning electron microscope. The surface topography was scanned by AFM technique.
Electrical Conductivity of SrRuO3 Thin Films Prepared by Laser Ablation
Authors: Ito Akihiko , Masumoto Hiroshi , Goto Takashi
Published: March 2009

SrRuO3 (SRO) thin films were prepared by laser ablation. The optimum preparation condition of highly electrically conductive SRO thin films was investigated. The substrate temperature (Tsub) was changed from room temperature to 973 K, and the deposition atmosphere was at a high vacuum (P = 10-6 Pa) and in O2 at oxygen pressures (PO2) of 0.13 and 13 Pa. The films
deposited at P = 10-6 Pa and PO2 = 0.13 Pa were amorphous structure. At Tsub > 573 K and PO2 = 13 Pa, well-crystallized pseudo-cubic SRO thin films with (110) orientation were obtained. With increasing Tsub, the conductivity of SRO films increased from 7.7×103 to 9.1×104 S·m-1. The epitaxially grown SRO films on (100) SrTiO3 substrates exhibited the highest conductivity of 1.8×105 S·m-1.
Delayed Hydride Cracking Velocity of Irradiated Zr-2.5Nb Tubes after a 30-Year Operation in the Wolsong Unit 1
Authors: Kim Young Suk , Ahn Sang Bok , Im Kyung Soo , Oh Wan H.
Published: March 2009

The aim of this study is to investigate a change in delayed hydride cracking (DHC) velocity of Zr-2.5Nb tubes with fast neutron fluence (E>1MeV) and predict the DHC velocity of the irradiated Wolsong 1 Zr-2.5Nb tubes at a neutron fluence corresponding to the 30 year design lifetime. To this end, the DHC velocity were determined at temperatures ranging from 100 to 280 oC on unirradiated Zr-2.5Nb tubes and the irradiated Zr-2.5Nb tubes in the Wolsong Unit-1 to the neutron fluence of 8.9x1025 n/m2 (E>1MeV). DHC tests were conducted on the compact tension specimens charged with 34 to 100 ppm hydrogen in accordance with the KAERI DHC procedures that have been validated through a round robin test on DHC velocity of Zr-2.5Nb tubes as an IAEA coordinated research project. Irradiated Zr-2.5Nb tubes had 3 to 5 times higher DHC velocity than that of unirradiated Zr-2.5Nb tubes while the inlet region of the irradiated Zr-2.5Nb tube with the highest yield strength had a slightly higher DHC velocity compared to that of the outlet region with the lowest yield strength. From a normalized correlation of yield strength and DHC velocity of the Zr-2.5Nb tubes, the yield strength was found to govern the DHC velocity of the Zr-2.5Nb tubes irrespective of the neutron fluence and operating temperatures. The DHC velocity of the irradiated Zr-2.5Nb tubes is predicted after a 30 year operation in the Wolsong Unit 1 on the basis of an increase in the yield strength with neutron fluence and a DHC velocity dependence on the yield strength of Zr-2.5Nb tubes.
Improvement of Vanadium Alloys by Precipitate Control for Structural Components of Fusion Reactors
Authors: Muroga Takeo , Nagasaka Takuya , Nishimura A. , Chen J.M.
Published: March 2009

Potential enhancement of mechanical properties of V-4Cr-4Ti by controlling precipitates of interstitial impurities (C, O and N) was investigated by means of various thermal and mechanical treatments. The increase in the cold working degree resulted in band structure of coarse Ti-CON precipitates having enhanced impact properties. Solid solution heat treatment followed by re-heating resulted in the formation of high density Ti-O-C precipitates enhancing high temperature strength. Combination of re-heating and cold rolling enhanced further the strength. Improvements in thermal and mechanical treatments are discussed for application of V-4Cr-4Ti to fusion structural materials.
Continuous Dynamic Recrystallization of AISI 430 Ferritic Stainless Steel by Hot Torsion Deformation
Authors: An Jae-Young , Han Suk Min , Kwon Young Jae , Yoo Yeon Chul
Published: March 2009

The high temperature deformation behavior of AISI 430 ferritic stainless steel has been studied over a temperature range of 800 to 1000°C and strain rate of 0.05-5.0/sec. The evolution of flow stress and microstructures showed the characteristics of continuous dynamic recrystallization (CDRX). The flow stress curves gradually decreased with increasing strain over the peak stress until 500% of strain without any steady state shown in typical austenitic stainless steel. Sub-grains of low angle firstly formed along the original high angle grain boundary were propagated into the inside of original grain and transformed to high angle. The CDRX grain sizes of AISI 430 deformed at 1000 °C and 0.5/sec was about 30-35㎛.