bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of NbC Precipitates and Nb in Solid-Solution on the Phase Transformation Kinetics in High-Purity Fe-C-Mn-Nb Alloys
Authors: Dere Emine Gözde , Sharma Hemant , Offerman S. Erik , Sietsma Jilt
Published: July 2011

The precipitation of NbC in austenite is an important mechanism for improving the strength of steel because NbC-precipitates are known to decrease the ferrite grain size during the subsequent phase transformations upon cooling. The effect of the interaction between niobium (Nb) in solid solution and NbC-precipitates on the austenite-to-ferrite phase-transformation kinetics is not entirely clear. We study a high-purity Fe-C-Mn-Nb alloy cooled at different rates. Different annealing times at 850°C were applied to create different number densities and sizes of the NbC-precipitates in order to study the effect of NbC precipitation on the transformation kinetics. The alloy that is used in this study has an atomic ratio of Nb:C=1.3:1. The fraction of ferrite is measured as a function of temperature during cooling by means of dilatometry. The ferrite grain size is measured by means of optical microscopy. The results are interpreted with thermodynamic and kinetic models.
Microstructural Evolution of AISI D2 Tool Steel during Aging
Authors: Farina Paula Fernanda Silva , Farina Alexandre Bellegard , Capo Julio , Padovese Linilson R. , Barbosa Celso A. , Goldenstein Hélio
Published: July 2011

The effects of low temperature isothermal treatments on a quenched AISI D2 tool steel was studied using Barkhausen Noise, X-ray diffraction, dilatometry and optical and electronic microscopy. The specimens were austenitized at 1040°C and quenched in oil. The isothermal treatments involved immersion in hot oil baths at 80° or 130°C for 0.1, 0.6, 1, 3, 10 and 30 hours, except for the dilatometry, in which the specimens were submitted to a single thermal cycle for 30 hours. These thermal treatments are industrially known as “stress relief treatments”, and are used to prevent cracks and catastrophic failures during cryogenic treatments. The comparison of global and local (microscopy) measurements allows the discussion of the phenomena involved in the aging process.
Ferrite Formation from Austenite; Effects of Length and Time Scales, Interface Type and Chemistry
Authors: Purdy Gary R.
Published: July 2011

The growth of ferrite from alloyed austenite can take many forms: Widmanstätten ferrite and “plessites” in meteoric Fe-Ni-Co; ferrite layer growth under decarburization conditions; grain boundary precipitation and Widmanstätten ferrite and bainite in alloy steels. This contribution considers ways in which these different aspects of austenite decomposition can inform one another.
Kinetic Transitions during Non-Partitioned Ferrite Growth in Fe-C-Mn Alloys
Authors: Panahi Damon , Bai Yun Fei , Zurob Hatem S. , Purdy Gary R. , Hutchinson Christopher R. , Bréchet Yves
Published: July 2011

Ferrite growth behavior in Fe-C-Mn alloys has been studied using controlled decarburization experiments. Two types of kinetic transition are considered. A first transition is proposed which involves a change from ParaEquibrium (PE) contact conditions at short times to Local-Equilibrium with Negligible Partitioning at longer times (LENP). This transition is attributed to the gradual build up of an alloying element spike due to the diffusion of Mn across the interface. The cross-interface mobility of Mn is estimated based on the experimental results. In some alloys, we observe a transition to extended PE states at high temperatures. A simple model which quantitatively describes the experimental observations over a range of composition and temperature is proposed. A key feature of this model is the introduction of an alloying element capacity of the moving ferrite/austenite interface, X*. The introduction of this quantity is purely guided by the experimental data and, at present, there is no physically based method for calculating it.
Investigation of Lath and Plate Martensite in a Carbon Steel
Authors: Stormvinter Albin , Borgenstam Annika , Hedström Peter
Published: July 2011

Martensite in carbon steels forms in different morphologies, often referred to as lath andplate martensite. The alloy composition has a strong effect on the morphology, for instance in car-bon steels there is a morphological change of the martensite microstructure from lath martensite atlow carbon contents to plate martensite at high carbon contents. In the present work a decarburizedhigh-carbon steel, enabling the isolation of carbons' influence alone, has been studied in order to in-vestigate the changes in morphology and hardness. From the results it is concluded that there is acontinuous change of hardness with increased carbon content. The increasing hardness slows down atabout 0.6 wt%C before decreasing at higher carbon contents. This is in accordance with the change inmorphology since it was found that lath martensite dominates below 0.6 wt%C and the first units ofgrain boundary martensite and plate martensite appear above 0.6 wt%C. At high carbon contents thedominating morphology is plate martensite, but retained austenite is also present.
Superficial Phase Transitions in Nanoalloys
Authors: Briki Mohamed , Creuze Jérôme , Berthier Fabienne , Legrand Bernard
Published: July 2011

In order to build the phase diagram of Cu-Ag nanoalloys, we study a 405-atom nanoparticle by means of Monte Carlo simulations with relaxations using N-body interatomic potentials. We focus on a range of nominal concentrations for which the cluster core remains Cu-pure and the (001) facets of the outer shell exhibit two original phenomena. Within the (N,mAg-mCu,P,T) ensemble, a structural and chemical bistability is observed, which affects all the (001) facets together. For a nanoparticle assembly, this will result in a bimodal distribution of clusters, some of them having their (001) facets Cu-rich with the usual square shape, the other ones having their (001) facets Ag-rich with a diamond shape. This bistability is replaced in the (NAg,NCu,P,T) ensemble by a continuous evolution of both the structure and the concentration of the (001) facets from Cu-rich square-shaped to Ag-rich diamond-shaped facets as the number of Ag atoms increases. For a nanoparticle assembly, this will result in an unimodal distribution of the cluster population concerning the properties of the (001) facets. This comparison between pseudo grand canonical and isothermal-isobaric results shows that the distribution of a population of bimetallic nanoparticles depends strongly on the conditions under it is elaborated.
Equilibrium Distribution of Alloyed Nanowires
Authors: Maras Emile , Braems Isabelle , Berthier Fabienne
Published: July 2011

The size distribution and the total density of clusters of a one-dimensional pure deposit can be expressed analytically from the Ising model. For a codeposit, the alloying effect and the presence of broken bonds at the cluster edges lead to inhomogeneities of the chemical composition of the clusters. We investigate the influence of codeposition on the size distribution of clusters in the case of an alloy that forms an ideal solution. We obtain the exact solution for the size distribution of clusters while the complete characterization of the system results from coupled analytical formulae in the grand-canonical ensemble. The results of this analytical model are successfully compared with those obtained by Monte Carlo simulations.
Microstructure Evolution of Mechanically Alloyed ODS Ferritic Steels during Hot Extrusion
Authors: Couvrat Mathieu , Chaffron Laurent , Nunes Daniel , Bonnaillie Patrick , Mathon Marie Hélène , Perrut Mikael
Published: July 2011

Direct hot extrusion of powder is the standard consolidation process to transform mechanically alloyed Oxide Dispersion Strengthened (ODS) steels into fully dense bars. It is a complex process including several steps. In this study, ODS steel bars were extruded and the material microstructure was characterized by TEM observations associated to SANS after each step. It was shown that the nano-cluster nucleation occurs during the powder pre-heating before hot-extrusion. During extrusion, the ferritic matrix undergoes a dynamic recovery but no further change of the nano-cluster distribution is observed.
Precipitation in a near Beta Titanium Alloy on Ageing: Influence of Heating Rate and Chemical Composition of the Beta-Metastable Phase
Authors: Settefrati Amico , Aeby-Gautier Elisabeth , Dehmas Moukrane , Geandier Guillaume , Appolaire Benoît , Audion Sylvain , Delfosse Jerôme
Published: July 2011

In the present study we focus on the precipitation processes during heating and ageing of β-metastable phase in the near β Ti-5553 alloy. Transformation processes have been studied using continuous high energy X-Ray Diffraction (XRD) and electrical resistivity for two different states of the β-metastable phase. Microstructures have been observed by electron microscopy. Different transformation sequences are highlighted depending on both heating rate and chemical composition of the β-metastable phase. At low temperatures and low heating rates, the hexagonal ωiso phase is first formed as generally mentioned in the literature. Increasing the temperature, XRD evidences the formation of an orthorhombic phase (α’’), which evolves toward the hexagonal pseudo compact α phase. For higher heating rates or for richer composition in β-stabilizing elements of the β-metastable phase, ω phase may not form and α’’ forms directly and again transforms into α phase. A direct transformation from β-metastable to a phase is observed for the highest heating rate. The formation of the metastable ωiso and α’’ phases clearly influences the final morphology of α.
Study of the Origin of the Unexpected Pearlite during the Cooling Stage of Two Cast High-Speed Steels
Authors: Tchoufang Tchuindjang Jérôme , Lecomte-Beckers Jacqueline
Published: July 2011

Two HSS grades (A and B) belonging to the complex system Fe-Cr-C-Si-X, where X is a strong carbide-forming element such as V, Mb or W, were studied. Samples in the as-received conditions came from an industrial spin casting process, with a varying cooling rate during processing. Chemical compositions of both alloys were closed to each other and were chosen to enhance their hardenability and to avoid less resistant phases such as pearlite and ferrite. Differential Thermal Analysis was performed on both alloys, in order to increase their crystallization behaviour. Light microscopy and SEM associated with EDS analyses were done to characterize the microstructure of both alloys in the as-received conditions and after DTA trials. The matrix of both HSS grades was composed of eutectic carbides, martensite and retained austenite, these phases exhibiting similar chemical compositions in both alloys. Unexpected pearlite was found in the as-cast HSS alloy B without W, this grade containing more Mo, more V and less Cr than the HSS grade A. It appeared from DTA tests that pearlite found in the alloy B arose more from the destabilisation of the Cr-rich retained austenite associated with the plate-like M2C carbide, than from the matrix itself. In fact, pearlite zones located in the vicinity of M2C are due to related isothermal solid phase transformations form the previous austenitic eutectic phase that is enriched with Cr and Mo.
Modelling of the Non-Isothermal Austenite Formation Kinetics of a X10CrMoVNb9-1 Martensitic Steel
Authors: Hanna Farah , Roux Guilhem Michel , Asserin Olivier , Brachet Jean-Christophe , Billardon René
Published: July 2011

This work is part of a collaborative study between CEA-Saclay and LMT-Cachan on the numerical simulation of multi-pass GTA-Welding of thick specimens made of X10CrMoVNb9-1 (ASTM 387 or “T91”) steel. This material is considered as a candidate for some components of future Very High Temperature nuclear Reactors. Some parts of these components should be manufactured by assembling thick components (typically 200 mm) using narrow groove multi-pass GTA-Welding process. This welding process generates complex thermo-mechanical cycles in the HAZ (Heat Affected Zone) inducing complex microstructural transformations and residual stresses which should affect the integrity of the vessels behaviour. In a previous study, G.-M. Roux [1] developed a first version of a Thermo-Metallurgical-Mechanical "TMM" model for the X10CrMoVNb9-1 martensitic steel. This model was validated regarding residual stresses on simple mono-pass spot-welding tests. In this paper, focus is made on the modelling of the complex austenitisation process of the tempered martensitic steel as induced by the multi-pass process. Three different approaches are presented, viz. a model first proposed by Brachet et al., second a new model based on JMA approach and last, the simple differential Leblond model that is implemented in various finite element codes. These models are identified from standard dilatometry tests performed over a large range of heating rates, viz. [0.1°C/s, 100°C/s]. Finally, the response of these models, and therefore, their predicting capabilities, are compared to the experimental response of the material for different transients that have been designed to be representative of the temperature history in different points of a multi-pass welding HAZ.
Magnetic Force Microscopic Description of the Structure of Glow Discharge Nitrided Layers Produced on Ni27Ti2AlMoNb Steel
Authors: Borowski Tomasz , Jeleńkowski Jerzy , Wierzchoń Tadeusz
Published: July 2011

The paper analyzes the magnetic properties and stability of austenite, athermal martensite, and deformation martensite that form in Ni27Ti2AlMoNb steel subjected to glow discharge assisted nitriding, and also of nitrogen austenite (S phase with various lattice constants) which occurs when the nitriding process is conducted below the temperature As. The analysis of these structural components and their morphology was performed using a magnetic force microscope (MFM), whereas the phase composition of the nitrided layers produced on this steel was determined by X-ray diffraction.
Thermodynamic Analysis of the Effect of Compositional Inhomogeneity on Phase Transformations in a 13Cr6Ni2Mo Supermartensitic Stainless Steel
Authors: Bojack Andrea , Zhao Lie , Sietsma Jilt
Published: July 2011

Supermartensitic stainless steels possess an excellent combination of strength, toughness and corrosion resistance and have attracted an increased industrial attention especially from the offshore oil and gas industry, where those materials are already successfully in use. It is well known that the mechanical properties of this type of steels are strongly dependent on the fraction of retained austenite, which is controlled by heat treatment. Because the products manufactured out of these steels are in large sections, temperature gradients and corresponding compositional inhomogeneities are inevitable. Also during heat treatment partitioning of elements between the phases will give local concentrations far removed from the bulk levels. In the present work a 13Cr6Ni2Mo supermartensitic stainless steel is thermodynamically analyzed using the Thermo-Calc® software package where the influence of compositional variations on phase transformations is investigated, in particular the effect of changes in the Ae3-temperature is discussed.
An Interpretation on Kinetics of Martensitic Transformation
Authors: Kakeshita Tomoyuki , Fukuda Takashi , Lee Yong-Hee
Published: July 2011

We have investigated athermal and isothermal martensitic transformations (typical displacive transformations) in Fe–Ni, Fe–Ni–Cr, and Ni-Co-Mn-In alloys under magnetic fields and hydrostatic pressures in order to understand the time-dependent nature of martensitic transformation, that is, the kinetics of martensitic transformation. We have confirmed that the two transformation processes are closely related to each other, that is, the athermal process changes to the isothermal process and the isothermal process changes to the athermal one under a hydrostatic pressure or a magnetic field. These findings can be explained by the phenomenological theory, which gives a unified explanation for the two transformation processes previously proposed by our group.
The Structure and the Evolution of Titanate Nanobelts, Used as Seeds for the Nucleation of Hydroxyapatite at the Surface of Titanium Implants
Authors: Conforto Egle , Caillard Daniel , Müller Lenka , Müller Frank
Published: July 2011

The phase transformations due to a sequence of chemical treatments leading to the nucleation and biomimetic growth of hydroxyl carbonated apatite (HCA) at the surface of titanium implants were studied by scanning and transmission electron microscopy in cross-section. In the first step, an acid etching forms a rough titanium hydride layer which remains unchanged after subsequent treatments. In the second step, soaking in a NaOH solution induces the growth of nanobelt tangles of nanocrystallized, monoclinic sodium titanate. In the third step, soaking in a simulated body fluid transforms sodium titanate into calcium and phosphorus titanate, by ion exchange in the same monoclinic structure. Then HCA, of a hexagonal structure, grows and embodies the tangled structure showing a preferential direction growth along its “c”-axis, perpendicular to the substrate surface. The interfaces between the different layers seem to be strong enough to prevent interfacial decohesion. The role of the titanate phase in the nucleation of HCA is finally discussed.
Phase Transformations on Friction Welding of Dissimilar Thermochemically Treated Steels
Authors: Mitelea Ion , Craciunescu Corneliu
Published: July 2011

The friction welding process provides a continuity of the joined materials at crystalline network level. This continuity is based on diffusion phenomena, on the forces of inter-atomic links as well as on the thermal and mechanical energy inputs. The action of the thermo-deformational field developed during the welding process is associated with solid phase transformations, influenced in terms of nature and intensity by the sensibility to mechanical hardening of the steel components, the critical quenching rate and the re-crystallization temperatures. The composition and microstructural gradients of thermochemically treated steels by carburization and nitriding leads to particularities in the morphology of the transformations induced in the welding plane. The work reports on the transformations observed in the joining plane explored by microstructural, hardness and impact testing.
Direct Spheroidization of High Carbon Steels: Effect of Thermomechanical Processing
Authors: Caruso Matteo , Verboomen Hector , Godet Stéphane
Published: July 2011

The eutectoid transformation of austenite can occur cooperatively (pearlite transformation) or by means of a non-cooperative mode (Divorced Eutectoid Transformation). In the cooperative mode, ferrite and cementite grow together, leading to the typical lamellar microstructure of pearlite. In the non-cooperative mode, spheroidal cementite particles grow directly from the undissolved carbides in the austenite phase. The transformation product is a fully spheroidized microstructure. In this study, the parameters promoting the occurrence of DET in a hypereutectoid steel (austenitization temperature, cooling rate, presence of proeutectoid cementite in the initial microstructure) were investigated. It is shown that low undercooling levels and a homogenous distribution of fine carbides in the austenite promote the DET over the lamellar transformation mode. The spheroidized microstructures produced by DET lead to larger ductilities comparing to those obtained by the lamellar transformation mode.
Thermodynamics of Stable and Metastable Cu-O-H Compounds
Authors: Korzhavyi Pavel A. , Soroka Inna , Boman Mats , Johansson Börje
Published: July 2011

We apply density functional perturbation theory together with experimental studies in order to investigate the structure and physical properties of possible stable and metastable copper(I) compounds with oxygen and hydrogen. Copper(I) hydride, CuH, is found to be a metastable phase which decomposes at ambient conditions and exhibiting a semiconducting gap in the electronic spectrum. The calculated structure and phonon spectra are found to be in good agreement with experimental data. The phonon spectra of a novel metastable phase, copper(I) hydroxide, are also determined.
Dependence of Vacancy-Solute Interactions on Magnetic State in Dilute Iron-Based Alloys
Authors: Gorbatov Oleg I. , Korzhavyi Pavel A. , Ruban Andrei V. , Gornostyrev Yuri N.
Published: July 2011

Vacancy-solute interactions play a crucial role in diffusion-controlled phase transformations, such as ordering or decomposition, which occur in alloys under heat treatment or under irradiation. The knowledge of these interactions is important for predicting long-term behavior of nuclear materials (such as reactor steels and nuclear-waste containers) under irradiation, as well as for advancing our general understanding of kinetic processes in alloys. Using first-principles calculations based on density functional theory and employing the locally self-consistent Green’s function technique, we develop a database of vacancy-solute interactions in dilute alloys of bcc Fe with 3p (Al, Si, P, S), 3d (Ti – Cu), and 4d (Nb – Ag) elements. Interactions within the first two coordination shells have been computed in the ferromagnetic state as well as in the paramagnetic (disordered local moment) state of the iron matrix. Magnetism is found to have a very strong effect on the vacancy-solute interactions.
Microstructural and Crystallographic Characteristics of Deformation-Induced Martensite Formed in Cold-Drawn 316 Type Stainless Steel
Authors: Nakada Nobuo , Ito Hidetoshi , Matsuoka Yoshikazu , Tsuchiyama Toshihiro , Takaki Setsuo
Published: July 2011

Deformation-induced martensite preferentially nucleates at the twin boundary between matrix austenite and deformation twin in 316 type stainless steel. In the cold-rolled specimen, the martensite formed at the twin boundary has K-S relationships with both of the austenite matrix and the deformation twin, that is, “double K-S relationship” is realized. While in the case of cold-drawn specimen, two kinds of twins with different twin planes are typically observed, and therefore, the deformation-induced martensites are formed at the intersections of the two deformation twin boundaries, satisfying “triple K-S relationship” among austenite matrix and two deformation twins, although there is a small misfit from the perfect K-S relationship. The complicated crystallographic orientation relationship leads to a strong variant restriction for deformation-induced martensites. Due to the difference in the number of nucleation sites, martensitic transformation is greatly promoted in cold-drawn specimen rather than cold-rolled one.
Experimental Study on Damage Mechanism of Nano-Ceramic Surface/Subsurface under Ultrasonic Vibration Aided Grinding
Authors: Zhao Bo , Zhao Chong Yang , Du Bao Yu
Published: July 2011

In this paper, surface/subsurface damage mechanism of engineering ceramics under ultrasonic vibration assisted grinding was studied by experiment based on its theoretical study. The study shows: under the same grinding conditions, ultrasonic grinding can realize plastic grinding and low crack damage surface grinding in a larger range of cutting depth than that under common grinding, that can improve processing efficiency and reduce workpiece grinding damage. Meanwhile, ultrasonic vibration grinding process can be seen as periodical loading and unloading process of abrasive on the workpiece. Crack is formed and extends initially on loading, the speed of crack expansion slows down, and its direction offsets to workpiece free surface on unloading as the change of ultrasonic force direction. So cracks can not expand to material deep and shallow sub-surface cracks are left in workpiece sub-surface layer. This phenomenon may be one of the main reasons that subsurface damage is reduced on ultrasonic grinding.
Study on Subsurface Damage after Fixed-Abrasive Lapping with Different Particle Size
Authors: Gao Ping , Li Jun , Zhu Yong Wei , Li Biao , Zhang Yan , Fan Ji Long , Sun Yu Li , Jiang Bi Liang , Zuo Dun Wen
Published: July 2011

Differential chemical etch method (DCEM) was employed to study the effect on the surface/subsurface damage depth of K9 glass lapped by different particle sizes of fixed diamond abrasives. The advantage of DCEM is that both the lapped and substrate samples are placed in the chemical etch at the same time to decrease or eliminate the effect of etching condition variation. K9 glasses are firstly fixed-abrasive lapped with 40, 28, 14 and 10μm diamond abrasives, respectively. Surface damages of K9 glass after FAL are measured by Microscopy. The results show that the corresponding subsurface damage (SSD) depths of K9 glass are 4.5, 3.4, 2.8 and 1.6μm when the fixed diamond abrasive particle size are 40, 28, 14 and 10μm.With the decreasing of diamond particle size, the SSD depth decreases obviously and surface quality of K9 glass is improved significantly.
Synthesis and Numerical Analysis on Velocity and Pressure Field of Convex Diamond Film
Authors: Li Duo Sheng , Zhou Xian Liang , Zuo Dun Wen , Hua Xiao Zhen
Published: July 2011

Maths model based on wo-dimensionalhas was built to simulate the velocity and pressure field of the growth of diamond film. Firtstly，the plasma jet flow is supposed as steady state incompressible gas, which meets with Reynolds-averaged Navier–Stokes equations. The model of the growth of convex diamond film considers different convex height of Mo substrate. The velocity and pressure field were simulated by CFD respectively.The simulational results show that, the distributions of velocity and pressure fields were fluctuant in reaction chamber. When convex height of Mo substrate was 9mm, DC plasma jet was smoother than the other heights, thus, we predicts that diamond film easily grows. Meanwhile, we prepared four diamond films in different heights of substrate, by DCPJCVD. Raman spectra were used to investigate the quality of convex diamond film. It was found that, when the height of convex substrate was 9mm, convex diamond film had only diamond characteristic peak. It is obvious that numerical analysis help us predict the distributions of velocity and pressure fields and synthesize high quality convex diamond film.
An Accurate Method for Calculating the Contact Subsurface Stress Field of Hybrid Ceramic Ball Bearing
Authors: Wang Cheng , Yu Wei , Ren Cheng Zu
Published: July 2011

In order to predict fatigue life of hybrid ceramic ball bearing (HCBB) by Ioannides and Harris (IH) theory, the contact subsurface stress field is needed. The contact surfaces of ball and race groove are compatible. The closed-form analytical solution of compatible contact problem is hard to be obtained. The Finite Element Method (FEM) together with submodel technology is adopted to accurately and efficiently calculate the contact deformation and subsurface stress of ball–race groove contact. The result indicated that, the FEM with submodel technology considers the real contact deformation of ball-race groove, and can accurately and efficiently calculate the subsurface stress field. It is believed that the calculated subsurface stress field can be used in IH theory to predict fatigue life of HCBB.
Influence of Cutting Parameters on Characteristics of Serrated Chip when High-Efficiency Cutting Ti6Al4V
Authors: Yang Shu Cai , Zheng Min Li , Zhang De Qiang , Liu Ning , Fan Yi Hang
Published: July 2011

During the process of high-efficiency cutting Ti6Al4V the material presents serrated chips. Periodic high-frequency serrated ship will cause fluctuations in the cutting force, which then affect the tool wear and surface integrity of workpiece and so on. On the basis of experiment of turning Ti6Al4V, the frequency and the geometric characteristics of serrated chip has been analyzed through observing the microstructure of chip using optical microscope and SEM. The results show that cutting speed and feed rate have great influence on the frequency and the geometric characteristics of serrated chip. Involving low-speed, large feed and large cutting depth can reduce the generated frequency of serrated chip.
Study on Effects of Cutter Radial Runout and Deformation on Cutting Force in Ball-End Hard Milling
Authors: Zhao Xing Fa , Liu Xian Li , Xiao Fei , Wang Yan Xin , Jiang Yan Cui
Published: July 2011

As cutter radial runout and deformation play a main role in processing precision, surface roughness and cutter wear during hard milling, the effects of the former two factors on actual cutting radius and cutting chip thickness are analyzed during milling process briefly in this paper. The vector direction of radius runout and deformation are assumed to be the same. Then, the milling force of cutting cutter whirling a circle is simulated under the three-dimensional feed motion, and the simulation result agrees well with the experimental result.
Research on the Edge Design Precision PCD Thread Milling Tool
Authors: Zheng Xiao Hu , Guo Guo Qiang , Li Jun Li , Chen Ming
Published: July 2011

This paper presented a method of FEM simulation in thread milling machining for designing PCD milling tool. Thread milling technology is a new method to replace common tapping process. PCD tool is proper for high efficiency aluminum machining. The proper geometries of PCD thread milling tool are gained by FEM method and the cutting test proved that PCD tool can instead the carbide thread tool and do better performance than that.
Wear of Milling Cutters in Machining of TC4 (Ti6Al4V) Titanium Alloys
Authors: Lai Jun Yi , Li Ling Xiang , Wu Chong Hu
Published: July 2011

Titanium alloys are difficult-to-cut materials, and the rapid wear of cutter is a big problem for machining of these alloys. In this paper, the wear characteristics of seven milling cutters in milling of TC4 (Ti6Al4V) titanium alloys are investigated. The results indicated that the averaged flank wear of each cutter linearly increases as the accumulated cutting length expands. Large radial rake angle as well as axial rake angle is favor for reducing cutter wear.
Energy and Material Removal Mechanisms for the Grinding of Cemented Carbide with Brazed Diamond Wheels
Authors: Zhan You Ji , Li Yuan , Huang Hui , Xu Xi Peng
Published: July 2011

An investigation was undertaken to explore the specific energy and material removal mechanisms involved in the grinding of cemented carbide with vacuum brazing diamond wheels. A mathematical model, relating to the grinding parameters such as wheel velocity, workpiece feedrate and depth of cut, was proposed to predict specific grinding energy, and was verified by experimental data. This verification came as a result of surface grinding two typical cemented carbides (YG8 and YG30) with a vacuum brazing diamond wheel under various grinding conditions. The earlier model’s prediction shows a direct correlation with the experimental results. Good relationships between the consumed power per unit width with the plowed face areas generated by all cutting points per unit width were obtained. Microscopic examination of the ground surfaces and the grinding detritus by a digital and video microscope system also revealed that material removal occurred mainly by flow-type chip formation (plastic flow) while grinding YG8 and by blocky fracture particles formation (brittle fracture) while grinding YT30.
Benefits and Drawbacks of Hydrogen Effect in Microstructure on Titanium Ti-6Al-4V Alloy
Authors: Sozańska Maria , Szkliniarz Wojciech
Published: July 2011

We present herein the effects of hydrogen on the microstructure of surface layers of two-phase titanium Ti-6Al-4V alloy. We describe the damage caused by hydrogen and the possibilities of using hydrogen as a temporary alloying element. The paper regarding the HTM - Hydrogen Treatment of Materials as an attractive method for controlling microstructure and improving final mechanical properties of titanium alloys. Hydrogen treatment consists of three stages: hydrogenation in a hydrogen gas atmosphere (600 °C), cyclic heat hydrogen treatment (300 °C), and dehydrogenation in vacuum (550 °C). We present the possibilities of hydrogen treatment for controlling the microstructure layer of titanium alloy and show results for the corrosion resistance of Ti-6Al-4V titanium alloy after hydrogen treatment. Information about the hydrogen effect on titanium alloys, based on selected publications and the authors’ experience, is also presented.
Modern Methods of Aluminum Alloys Welding
Authors: Adamiec Janusz , Pfeifer Tomasz , Rykała Janusz
Published: July 2011

The article presents the course and the results of research on material and technological welding conditions of different aluminium alloys using low energy welding methods (CMT and ColdArc) as well as discusses the properties of welded joints and the application fields of modern low energy welding devices for joining thin aluminium sheets.
AlSi7Mg/SiC and Heterophase SiCP+CG Composite for Use in Cylinder-Piston System of Air Compressor
Authors: Dyzia Maciej
Published: July 2011

The article presents the results of the first phase of research on the development of manufacturing composites by pilot-scale technology. Producing of composite suspension in sufficient quantity to obtain approximately 50 casting pistons in one production cycle was the aim of this study. This allowed to assess the stability of the composite suspension manufacturing process and above all stability the casting process. Composite suspension (AlSi7Mg/SiCp and heterophase SiCp+Cg ) were prepared in one technological cycle including refining and modification of the alloy matrix, the introduction of ceramic particles and the homogenization of the suspension under reduced pressure. Objective of this study was to determine the basic parameters of the suspension of the manufacturing process, such as metal refining period, the rate of particles introduction and time of homogenization. In addition, as a evaluation criterion of quality the manufactured composite material accepted the possibility of pre-cast piston machining.
Characteristics of Eutectic Precipitations in Selected Magnesium Cast Alloys
Authors: Szala Janusz
Published: July 2011

. The paper focuses on characterization of eutectic precipitations in three magnesium alloys (MSR-B, ZRE1 and WE43) containing rare earth elements. It was shown, that the structure of the tested alloys in a cast state consists of globular grains of the α-Mg solid solution and eutectic areas of different chemical composition and morphology. An untypical influence of the pouring temperature on the eutectic precipitations area fraction was observed. This phenomenon can be explained by impoverishment of the eutectic-forming elements in the areas of the slowest solidification. This results from the fact, that at the highest pouring temperature a considerable amount of eutectic forms in places solidified as the first.
Solidification Process, Microstructure, Density and Hardness of the Mg-Al Alloys with Zn, Cu, Ni and AlTiB Additions
Authors: Binczyk Franciszek
Published: July 2011

The paper presents the results of the investigations of the solidification process of magnesium alloys containing 5 and 10 wt.% Al, the additions of Zn, Cu, Ni, and of an AlTiB master alloy. The plotted DTA (derivative thermal analysis) curves were used for the determination of solidification parameters Tliq, Teut and Tsol. Knowledge of these parameters is very important in determination of alloy pouring temperature and maximum casting operating temperature. On samples taken from the area of temperature measurements, the chemical composition and microstructure were determined. The density and hardness HB were measured as well. Applying the method of multiple regression analysis at the significance level α = 0.1, the intensity and direction of the effect of alloying elements on the solidification parameters, density and hardness HB of castings were evaluated.
Innate Immune Collectin Surfactant Protein D Simultaneously Binds Both Neutrophil Extracellular Traps and Carbohydrate Ligands and Promotes Bacterial Trapping
Authors: Douda David Nobuhiro , Jackson Richard , Grasemann Hartmut , Palaniyar Nades
Published: July 2011

Neutrophils release DNA-based extracellular traps to capture and kill bacteria. The mechanism(s) and proteins that promote neutrophil extracellular trap (NET)-mediated bacterial trapping are not clearly established. Surfactant protein D (SP-D) is an innate immune collectin present in many mucosal surfaces. We hypothesized that SP-D can bind both the pathogens and NETs to augment NET-mediated bacterial trapping. To test this hypothesis, we used LPS and Pseudomonas aeruginosa pneumonia mouse models and performed in vivo and ex vivo assays. In this study, we show that NETs are produced by the neutrophils recruited to the airways in response to the bacterial ligand. Notably, NETs are detected as short fragments of DNA–protein complexes in the airways as opposed to the long stringlike structures seen in ex vivo cultures. SP-D recognizes both the short NET fragments and the long NET DNA structures. SP-D–NET copurification studies further show that SP-D can simultaneously recognize NETs and carbohydrate ligands in vivo. Similar to the LPS model, soluble DNA–protein complexes and increased amounts of SP-D are detected in the murine model of P. aeruginosa pneumonia. We then tested the effect of SP-D on NET-mediated trapping of P. aeruginosa by means of Western blots, fluorescence microscopy, and scanning electron microscopy. Results of these experiments show that SP-D microagglutinates P. aeruginosa and allows an efficient bacterial trapping by NETs. Collectively, these findings provide a unique biological relevance for SP-D–DNA interactions and places SP-D as an important innate immune protein that promotes bacterial trapping by NETs during neutrophil-mediated host defense.
Protective Roles for Fibrin, Tissue Factor, Plasminogen Activator Inhibitor-1, and Thrombin Activatable Fibrinolysis Inhibitor, but Not Factor XI, during Defense against the Gram-Negative BacteriumYersinia enterocolitica
Authors: Luo Deyan , Szaba Frank M. , Kummer Lawrence W. , Plow Edward F. , Mackman Nigel , Gailani David , Smiley Stephen T.
Published: July 2011

Septic infections dysregulate hemostatic pathways, prompting coagulopathy. Nevertheless, anticoagulant therapies typically fail to protect humans from septic pathology. The data reported in this work may help to explain this discrepancy by demonstrating critical protective roles for coagulation leading to fibrin deposition during host defense against the Gram-negative bacterium Yersinia enterocolitica. After i.p. inoculation with Y. enterocolitica, fibrinogen-deficient mice display impaired cytokine and chemokine production in the peritoneal cavity and suppressed neutrophil recruitment. Moreover, both gene-targeted fibrinogen-deficient mice and wild-type mice treated with the anticoagulant coumadin display increased hepatic bacterial burden and mortality following either i.p. or i.v. inoculation with Y. enterocolitica. Mice with low tissue factor activity succumb to yersiniosis with a phenotype similar to fibrin(ogen)-deficient mice, whereas factor XI-deficient mice show wild-type levels of resistance. Mice deficient in plasminogen activator inhibitor-1 or thrombin-activatable fibrinolysis inhibitor display modest phenotypes, but mice deficient in both plasminogen activator inhibitor-1 and thrombin-activatable fibrinolysis inhibitor succumb to yersiniosis with a phenotype resembling fibrin(ogen)-deficient mice. These findings demonstrate critical protective roles for the tissue factor-dependent extrinsic coagulation pathway during host defense against bacteria and caution that therapeutics targeting major thrombin-generating or antifibrinolytic pathways may disrupt fibrin-mediated host defense during Gram-negative sepsis.
The Inhibiting Fc Receptor for IgG, FcγRIIB, Is a Modifier of Autoimmune Susceptibility
Authors: Boross Peter , Arandhara Victoria L. , Martin-Ramirez Javier , Santiago-Raber Marie-Laure , Carlucci Francesco , Flierman Roelof , van der Kaa Jos , Breukel Cor , Claassens Jill W. C. , Camps Marcel , Lubberts Erik , Salvatori Daniela , Rastaldi Maria Pia , Ossendorp Ferry , Daha Mohamed R. , Cook H. Terence , Izui Shozo , Botto Marina , Verbeek J. Sjef
Published: July 2011

FcγRIIB-deficient mice generated in 129 background (FcγRIIB129−/−) if back-crossed into C57BL/6 background exhibit a hyperactive phenotype and develop lethal lupus. Both in mice and humans, the Fcγr2b gene is located within a genomic interval on chromosome 1 associated with lupus susceptibility. In mice, the 129-derived haplotype of this interval, named Sle16, causes loss of self-tolerance in the context of the B6 genome, hampering the analysis of the specific contribution of FcγRIIB deficiency to the development of lupus in FcγRIIB129−/− mice. Moreover, in humans genetic linkage studies revealed contradictory results regarding the association of “loss of function” mutations in the Fcγr2b gene and susceptibility to systemic lupus erythematosis. In this study, we demonstrate that FcγRIIB−/− mice generated by gene targeting in B6-derived ES cells (FcγRIIBB6−/−), lacking the 129-derived flanking Sle16 region, exhibit a hyperactive phenotype but fail to develop lupus indicating that in FcγRIIB129−/− mice, not FcγRIIB deficiency but epistatic interactions between the C57BL/6 genome and the 129-derived Fcγr2b flanking region cause loss of tolerance. The contribution to the development of autoimmune disease by the resulting autoreactive B cells is amplified by the absence of FcγRIIB, culminating in lethal lupus. In the presence of the Yaa lupus-susceptibility locus, FcγRIIBB6−/− mice do develop lethal lupus, confirming that FcγRIIB deficiency only amplifies spontaneous autoimmunity determined by other loci.
Patient-Specific Pluripotent Stem Cells in Neurological Diseases
Authors: Durnaoglu Serpen , Genc Sermin , Genc Kursad
Published: July 2011

Many human neurological diseases are not currently curable and result in devastating neurologic sequelae. The increasing availability of induced pluripotent stem cells (iPSCs) derived from adult human somatic cells provides new prospects for cellreplacement strategies and disease-related basic research in a broad spectrum of human neurologic diseases. Patient-specific iPSC-based modeling of neurogenetic and neurodegenerative diseases is an emerging efficient tool forin vitromodeling to understand disease and to screen for genes and drugs that modify the disease process. With the exponential increase in iPSC research in recent years, human iPSCs have been successfully derived with different technologies and from various cell types. Although there remain a great deal to learn about patient-specific iPSC safety, the reprogramming mechanisms, better ways to direct a specific reprogramming, ideal cell source for cellular grafts, and the mechanisms by which transplanted stem cells lead to an enhanced functional recovery and structural reorganization, the discovery of the therapeutic potential of iPSCs offers new opportunities for the treatment of incurable neurologic diseases. However, iPSC-based therapeutic strategies need to be thoroughly evaluated in preclinical animal models of neurological diseases before they can be applied in a clinical setting.
Breast Cancer Preoperative Staging: Does Contrast-Enhanced Magnetic Resonance Mammography Modify Surgery?
Authors: Perono Biacchiardi Chiara , Brizzi Davide , Genta Franco , Zanon Eugenio , Camanni Marco , Deltetto Francesco
Published: July 2011

Women with newly diagnosed breast cancer may have lesions undetected by conventional imaging. Recently contrast-enhanced magnetic resonance mammography (CE-MRM) showed higher sensitivity in breast lesions detection. The present analysis was aimed at evaluating the benefit of preoperative CE-MRM in the surgical planning. From 2005 to 2009, 525 consecutive women (25–75 years) with breast cancer, newly diagnosed by mammography, ultrasound, and needle-biopsy, underwent CE-MRM. The median invasive tumour size was 19 mm. In 144 patients, CE-MRM identified additional lesions. After secondlook, 119 patients underwent additional biopsy. CE-MRM altered surgery in 118 patients: 57 received double lumpectomy or wider excision (41 beneficial), 41 required mastectomy (40 beneficial), and 20 underwent contra lateral surgery (18 beneficial). The overall false-positive rate was 27.1% (39/144). CE-MRM contributed significantly to the management of breast cancer, suggesting more extensive disease in 144/525 (27.4%) patients and changing the surgical plan in 118/525 (22.5%) patients (99/525, 18.8% beneficial).
Salivary Gland Tumors in Maxillofacial Region: A Retrospective Study of 130 Cases in a Southern Iranian Population
Authors: Shishegar Mahmoud , Ashraf Mohamad J. , Azarpira Negar , Khademi Bijan , Hashemi Basir , Ashrafi Amir
Published: July 2011

Tumors of the salivary glands are uncommon head and neck neoplasia. We conducted a retrospective study of 392 cases over the last 6 years in Shiraz, south of Iran, to investigate the clinicopathological features of these tumors in Iranian population. The age of the patients ranged from 8 to 85 years, with the mean age years and male-to-female (M : F) ratio was 1.02 : 1. For benign tumors, there was a propensity towards females, whereas the malignant tumor was more common in males. The ratio of benign tumors to malignancies was 2.19 : 1. Pleomorphic adenoma (PA) was the most common tumor and accounted for 85% of all benign tumors, followed by Warthin's tumor (8.6%). Of the 125 malignancies, adenoid cystic carcinoma (40%), mucoepidermoid carcinoma (24%) and invasive squamous cell carcinoma (16%) were the most common histological types. Most of the salivary gland tumors (75%) originated from major salivary glands and the remained (25%) originated from minor glands. The parotid gland was the most common site both in benign and malignant tumors. Most of our findings were similar to those in the literature, with some variations. The salivary tumors slightly predominated in males. Adenoid cystic carcinoma and mucoepidermoid carcinoma constituted the most common malignancies.
Understanding the anatomy of religion as basis for religion in education
Authors: Van der Walt Johannes L.
Published: July 2011

This article sprung from previous structural analyses of religion as onticity, but went somewhat further by placing more emphasis on encounters with the numinous as the core of religion, as well as on the dynamic character of religion. In doing so, this analysis methodologically transcended the limitations of a structuralist view of religion. The post-structuralist approach that was followed, assigns greater prominence to the interpretive and constructivist activities of the actors involved in religious experience. Application of this expanded view of religion to the South African Policy on Religion and Education (2003) demonstrated that the Policy caused a break between the various facets of religion education and resultantly disrupted the wholeness of religion education.