bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of Ni-substitution on physical Properties of Fe72-xB24Nb4Nix Bulk Metallic Glassy Alloys
Authors: Masood Ansar , Biswas Anis , Ström V. , Belova L. , Ågren J. , Rao K. V. 
Published: April 2011

ABSTRACTWe have succeeded in producing bulk metallic glass by partial substitution of Fe with Ni in Fe-B-Nb alloys which could otherwise be only melt spun into amorphous ribbons. Substitution by Ni in the Fe72-xB24Nb4Nix alloys with (x ~2, 4, 6, 8, 10, 12 and 14) improves the glass forming ability of the materials and as a result rods of same compositions can be fabricated. Magnetically the BMG alloys remain soft with coercitivities below 500 mOe- However, the electrical resistivity of the system decreases significantly by as much as a factor of two with the increase of Ni concentration, and becomes more metallic like with a positive temperature coefficient.
Time-of-Flight Characterization of Single-crystalline CVD Diamond with Different Surface Passivation Layers
Authors: Kovi Kiran Kumar , Majdi Saman , Gabrysch Markus , Friel Ian , Balmer Richard , Isberg Jan 
Published: April 2011

ABSTRACTThe electronic properties of diamond, e.g. a high band-gap and high carrier mobilities, together with material properties such as a very high thermal conductivity, chemical inertness and a high radiation resistance makes diamond a unique material for many extreme electronic applications out of reach for silicon devices. This includes, e.g. microwave power devices, power devices and high temperature electronics. It is important to have an effective passivation of the surface of such devices since the passivation determines the ability of the device to withstand high surface electric fields. In addition, the passivation is used to control the surface charge which can strongly influence the electric field in the bulk of the device. It is possible to measure sample parameters such as electron and hole drift mobilities, charge carrier lifetimes or saturation velocities using Time-of-flight (ToF) method. The ToF technique has also been adapted for probing the electric field distribution and the distribution of trapped charge. In this paper we present new data from lateral ToF studies of high-purity single crystalline diamond with different surface passivations. Silicon oxide and silicon nitride are used as passivation layers in the current study. The effect of the passivation on charge transport is studied, and the results of different passivation materials are compared experimentally.
Alloying Effects on the Stability of γ/γ′ Microstructure in Co-Al-W Base Alloys
Authors: Tsukamoto Yuki , Kobayashi Satoru , Takasugi Takayuki 
Published: April 2011

ABSTRACTThe aim of this study is two-fold: first we reexamine the thermodynamic stability of γ’-Co3(Al,W) phase in the Co-Al-W ternary system. Secondly, we investigate the effect of a fourth alloying element (Ti or Ta) on the thermodynamic stability of the γ’ phase through microstructure observation, DSC measurement and EPMA analysis. Coarsened areas with γ/CoAl/Co3W phases are formed after annealing at 900 ºC for 2000 h in Co-Al-W ternary alloys with different Al/W ratios, which confirms that the three phases are in equilibrium with each other and that the γ’ phase is metastable at this temperature. The addition of a fourth alloying elements does not drastically change the microstructure formed after long term annealing at 900 ºC, indicating that the alloying elements do not improve the stability of the γ’ phase.
Comparison of Different Fluorine-treatments for Improved High Temperature Oxidation Resistance of TiAl-alloys
Authors: Donchev A. , Schütze M. , Kolitsch A. , Yankov R. 
Published: April 2011

ABSTRACTIntermetallic TiAl-alloys can replace the heavier Ni-based superalloys in several high temperature applications with regards to their mechanical properties, however they can not be used at temperatures above 800°C in oxidizing environments for longer times because of insufficient oxidation resistance. Despite an Al-content of about 45 at.% in technical alloys, no protective alumina layer is formed because the thermodynamic stabilities of titanium oxide and aluminum oxide are of the same order of magnitude. Therefore a mixed TiO2/Al2O3-scale is formed which is fast growing so that the metal consumption rate is quite high. On the other hand the formation of a slow growing alumina layer is promoted by a fluorine treatment. This so called fluorine effect leads to the preferential intermediate formation of gaseous aluminum fluorides at elevated temperatures if the fluorine content at the surface stays within a defined concentration range. These fluorides are converted into solid Al2O3 due to the high oxygen partial pressure of the high temperature service environment forming a protective pure Al2O3 surface scale. In this paper results of high temperature oxidations tests of several technical TiAl-alloys will be presented. Different F-treatments e.g. dipping or spaying which are easy to apply have been used and their results will be compared. The mass change data of the F-treated specimens are always lower than those of the untreated ones. Post experimental investigations such as light microscopy, scanning electron microscopy and energy dispersive X-ray analysis reveal the formation of a thin alumina layer on the F-treated samples after optimization of the process while a thick mixed scale is found on the untreated samples. The results will be discussed in view of an optimized procedure and the future use of TiAl-components in high temperature environments.
Atom probe tomography analysis of Ti-Y-O clustering during processing of nanoscale oxide particles in 14%Cr ODS ferritic steels
Authors: Williams Ceri A. , Unifantowicz Paulina , Oksiuta Zbigniew , Baluc Nadine , Smith George D. W. , Marquis Emmanuelle A. 
Published: April 2011

ABSTRACTAtom probe tomography is used to investigate the clustering of Y-Ti-O in a 14%Cr-2%W-0.3%Ti & 0.3% Y2O3 ODS steel. The clusters in the consolidated material are compared to clusters observed in the powder prior to consolidation. A higher density of smaller clusters is observed in the powder, and the clusters are found to contain more O and less Y.
SOI Waveguide Optical Nonreciprocal Devices with Directly Bonded Garnet
Authors: Mizumoto Tetsuya , Takei Ryohei 
Published: April 2011

ABSTRACTSurface activated direct bonding of a magnetooptic garnet crystal to a Silicon-On-Insulator (SOI) wafer is discussed for the application to waveguide optical nonreciprocal devices. An interferometric waveguide isolator is discussed that uses nonreciprocal phase shift brought about by a first-order magneto-optic effect. In an SOI waveguide, the low refractive index of buried oxide layer enhances the magneto-optic phase shift. This contributes to reduce the device size together with the strong field confinement of high index contrast waveguide. The interferometric isolator can be extended to an optical circulator by adopting appropriate 3-dB directional couplers to construct a Mach-Zehnder interferometer.
Hard magnetic materials based on Nd9(Fe,B)87Zr2Nb2 nanograined intermetallic compounds
Authors: Kumon Shoichi , Nishimoto Kazue , Fukuzaki Tomokazu , Tamura Ryuji 
Published: April 2011

ABSTRACTMagnetization behavior of Nd9(Fe, B)87Zr2Nb2 nanostructure magnets have been investigated. We will show that the nanostructure magnets are composed of magnetic clusters of exchange-coupled single domains and the coercivity is governed by coupling intensity between soft and hard magnetic clusters in the magnets.
Microfracture Test of Mg12ZnY Intermetallic Compound in Mg-Zn-Y Alloys
Authors: Yoshimura Hajime , Matsuyama Shun , Matsuda Mitsuhiro , Otsu Masaaki , Takashima Kazuki , Kawamura Yoshihito 
Published: April 2011

ABSTRACTA Mg-Zn-Y alloy including a Mg12ZnY intermetallic compound exhibits excellent mechanical properties as compared to conventional magnesium alloys. The superior mechanical properties of this alloy seem to originate from the Mg12ZnY intermetallic compound; however, the mechanical properties of Mg12ZnY itself have not yet been fully investigated owing to the small size of this compound. In this study, a microfracture test was performed to investigate the fracture properties of the Mg12ZnY intermetallic compound. The material used in this test was a Mg88Zn5Y7 alloy. Micro-sized cantilever specimens composed of Mg12ZnY, with dimensions of 10 × 20 × 50 μm3, were prepared selectively isolated from the Mg88Zn5Y7 alloy using focused ion beam (FIB) machining. Notches with a width of 0.5 μm and a depth of 5 μm were also introduced into the micro-sized specimens. Microfracture tests were performed using a mechanical testing machine for microscale materials. The fracture toughness values (KQ) of Mg12ZnY were 1.2−3.0 MPam1/2. TEM observations indicated that the KQ values were dependent on the crack orientation in Mg12ZnY, with the higher KQ values correlating with cracks propagating parallel to the c-axis of Mg12ZnY. This suggests that the fracture toughness of Mg-Zn-Y alloys can be improved by controlling the orientation of the Mg12ZnY compound.
Quarternary and Quinary Additions to Directionally-Solidified X-X3Si Eutectics of Chromium and Vanadium
Authors: Ang J , Vorontsov VA , Hayward CL , Balakrishnan G , Stone HJ , Rae CMF 
Published: April 2011

ABSTRACTAn alternative high temperature structural alloy system based on the X-X3Si eutectic compositions of chromium and vanadium is put forward. These low-density (~6g/cm3) eutectics have a bcc solid-solution to increase alloy fracture toughness, and a A15 X3Si as the high temperature load-bearing phase. (½Cr,½V)-(½Cr,½V)3Si was used as the base alloy for further element additions, and is represented by the symbol 山 10at.% tantalum and aluminium were substituted for vanadium as quaternary and quinary alloy additions.Microstructure, elemental phase partitioning, compression creep and oxidation results will be discussed. Cr-Cr3Si has a tidy, fine lamellar microstructure. Vanadium coarsens and destabilises the lamellae to a limited extent. Tantalum addition causes two distinct populations of eutectic to form; one population having finer lamellae than the other. Aluminium does not coarsen or destabilise the lamellar microstructure. High temperature compression tests at 1200°C and 1300°C show that 山 is stronger than the binary alloys, and of similar strength to the quaternary and quinary alloys.
‘In-situ’ Solution Processed Room Temperature Ferromagnetic MgO Thin Films Printed by Inkjet Technique
Authors: Wu Yan , Zhan Yiqiang , Fahlman Mats , Fang Mei , Rao K. V. , Belova Lyubov 
Published: April 2011

ABSTRACTWe report on ‘in-situ’ solution processed homogeneous (200) oriented MgO ~85nm thin films deposited on Si substrates by inkjet printing. These films are found to show ferromagnetic order beyond room temperature with a saturation magnetization MS as high as ~0.63 emu/g. X-ray photoelectron spectroscopy investigations show the absence of any possible contamination effects, while the Mg 2p, and O 1s spectra indicate that the role of defect structure at the Mg site is important in the observed magnetism. By controlling the pH values of the precursors the concentration of the defects can be varied and hence tune the magnetization at room temperature. The origin of magnetism in these MgO thin films appears to arise from the cation vacancies.
Radiation damage studies of nuclear ceramics using the JANNUS-Saclay triple -ion beam irradiation platform
Authors: Trocellier P. , Miro S. , Serruys Y. , Bordas É. , Martin H. , Chaâbane N. , Pellegrino S. , Vaubaillon S. , Gallien J.P. 
Published: April 2011

AbstractThe third accelerator of the multi-ion irradiation platform JANNUS (Joint Accelerators for Nanosciences and NUclear Simulation), a 6SDH-2 Pelletron from National Electrostatic Corporation, Middleton was installed at Saclay in October 2009. The first triple beam irradiation combining Fe, He and H ion beams has been performed in March 2010 on a Fe-12Cr model ODS alloy. In the first part of this paper, we give a technical description of the triple beam facility. Then, we present its performances and experimental capabilities. Typically, damage dose up to 100 dpa can be reached in 10 hours irradiation with heavy ion beams, with or without simultaneous bombardment by protons, helium-4 ions or any other heavy ion beam. In the second part of this paper, we illustrate some recent experiments relative to advanced nuclear ceramics and composite materials developed in the frame of the Generation IV Forum research program or for fusion applications.
Fabrication of Low Cost 1D CdSe Nanowires using Near-field Electrospinning
Authors: Magwood Leroy , Starly Binil 
Published: April 2011

ABSTRACTWell-aligned, 1D CdSe quantum dot (QD) fibers (0.3μm to 2.5μm) containing up to 20wt% fluorescent quantum dots (QDs) were prepared by near-field electrospinning (NFES) process. Electrospun solutions were prepared using PVAc as the matrix polymer, dimethyl formamide (DMF) solvent and colloidal QDs in chloroform (CHCl3). The diameter of the fibers decreased as the ratio of DMF/CHCl3 is varied. QDs showed good dispersion and a linear relationship between QD loading and fiber diameter, as determined by the morphology measurements taken using TEM and SEM, respectively. Fluorescence microscopy shows that there is light attenuation throughout the fibers. Results also show that the NFES process may be used as a method to create aligned, 1D fibers of QDs and potentially other nanofibers.
Microstructure and Oxidation Resistance of Cr-Ta-Si alloys
Authors: Bhowmik Ayan , Pang Hon Tong , Neumeier Steffen , Stone Howard J. , Edmonds Ian 
Published: April 2011

ABSTRACTThe phase equilibria and oxidation resistance of alloys lying near the Cr-rich end of the Cr- Ta-Si system have been investigated. Samples were prepared by arc-melting and homogenized at 1300°C for 500hrs. Identification of the phases present and their compositions were carried out using x-ray diffraction and electron probe micro-analysis and the ternary phase diagram on the Cr-rich end was plotted. A three-phase equilibria was found to exist between an A2 Cr-solid solution, a hexagonal Laves phase and the A15 Cr3Si intermetallic phase for alloys with higher contents of Si.Thermo-gravimetric analysis of the alloys at 1100°C demonstrated an improvement in the oxidation resistance of the ternary alloys with increasing Si-content. The microstructures of the oxidized samples revealed the formation of a thick chromia layer on top of a Cr,Ta-mixed oxide layer and an internal oxidation zone for all the alloys. A protective silica layer was not observed to form in any of the alloys tested.
Pseudoelasticity of D03-Type Fe3Al and Fe3Ga-Based Alloys
Authors: Yasuda Hiroyuki Y. , Umakoshi Yukichi 
Published: April 2011

ABSTRACTThe pseudoelastic behavior of Fe3Al and Fe3Ga alloys with the D03 structure is reviewed. In general, pseudoelasticity of shape memory alloys is based on a thermoelastic martensitic transformation. However, pseudoelasticity regardless of the martensitic transformation is found to take place in D03-ordered Fe3Al and Fe3Ga alloys. For instance, a 1/4<111> superpartial dislocation in Fe3Al alloys moves independently dragging an antiphase boundary (APB). During unloading, the APB pulls back the superpartial to decrease its energy resulting in pseudoelasticity, which is called “APB pseudoelasticity”. Moreover, D03-type Fe3Ga alloys were found to demonstrate three types of pseudoelasticity based on the dislocation motion, twinning and martensitic transformation depending on the chemical composition, degree of D03 order, loading axis, stress sense and deformation temperature. The mechanism of the pseudoelasticities in the D03-type intermetallics is discussed based on some in situ observations. The effects of chemical composition, deformation temperature and crystal orientation on the pseudoelastic behaviors are also discussed.
Irradiation behaviour of Precipitation Hardened Ni-base Super-alloys with EHP Grade under Multi-ion Irradiation
Authors: Kim Gwang-Ho , Shiba Kiyoyuki , Sawai Tomotsugu , Ioka Ikuo , Kiuchi Kiyoshi 
Published: April 2011

ABSTRACTThe irradiation behaviour in two different precipitation hardening types of Ni-base alloys with the ultra high purity grade (EHP), namely, the γ’ type and G phase type was investigated by multi-ion beam techniques simulated to the irradiation conditions in fuel cladding tubes used in sodium cooled FBRs. Single ion-beam irradiation tests were conducted up to 90 dpa (by Fe3+ or Ni3+) at 673 K. Triple ion-beam irradiation tests were conducted up to 90 dpa (by Ni3+, 90 appmHe and 1350 appmH) at 823K. The irradiation behaviour was examined by and the microscopic observation by TEM to the distribution of dislocations, cavities and voids. The behaviour was compared with those of PNC316. The dominating irradiation defects in EHP(γ’) alloy at 673 K by single ion-beam are Frank loops, perfect unfaulted loops and line dislocations. Whereas, those of EHP(WSi) alloy are the irradiation-induced γ’ (Ni3Si) precipitates along {111} planes. Those dominating defect structures at 823 K by triple ion-beam are classified as followings, bimodal distributions in EHP(γ’), bubbles in EHP(WSi) and voids in PNC316. From those results, the excellent irradiation properties of EHP(WSi) alloy is clarified as the inhibition effects of secondary irradiation defects.
Mechanical and Electrical Properties of Rapidly Solidified Cu-Zr-Ag Alloy Fabricated by Powder Rolling Process
Authors: Miyakawa Satoru , Nishida Motonori , Nishiyama Nobuyuki , Miura Haruko , Inoue Akihisa 
Published: April 2011

ABSTRACTA non-equilibrium Cu-Zr-Ag alloy was designed for the development of an alternative electric connector to Cu-Be alloys. This work aims at producing a Cu-Zr-Ag sheet using a hot-powder-rolling (HPR) process. The sheets were produced by a sequential process of HPR, pre-annealing, and cold rolling, using Cu93.5Zr5.5Ag1 (at.%) alloy powder produced by an argon gas atomization method. The Cu93.5Zr5.5Ag1 alloy sheet has a tensile strength of 1188 MPa and a conductivity of 33.2% IACS, which are similar values to those of Cu-Be alloys. In this paper, we optimize the conditions of the HPR process and reveal the correlation between the microstructure and properties of the Cu-Zr-Ag sheet produced by the HPR process. In addition, we discuss the alloy’s applicability for use as a connecter material.
Both Luminous Efficiency and Lifetime Enhancement in Blue
Fluorescence OLEDs by Modifying Molecular Structure of Hole Transporting
Material
Authors: Kwak Yoonhyun , Lee Sun-Young , Jeong Hye-In , Shin Dae-Yup , Song Young-Woo , Lee Jong Hyuk , Kim Sung Chul 
Published: April 2011

ABSTRACTBoth luminous efficiency and lifetime in blue fluorescence organic light
emitting devices (OLEDs) have been improved by modified HTMs with higher
LUMO energy levels. The LUMO energy levels of HTM were increased by
modifying substituent in HTM molecules. Two HTMs containing ortho and meta
biphenyl substituent and one HTM containing thiophene substituent were
synthesized via palladium catalyzed amine coupling reactions to compare with
a para biphenyl substituent HTM-1 as a standard molecule. According to TDDFT
calculations, these three modified HTMs showed 0.05-0.15 eV higher LUMO
energy levels compared to the para biphenyl substituent HTM-1. The luminous
efficiency and the lifetime (LT90) of OLEDs using HTM-2 at 500
cd/m2 have been enhanced up to 20 % and 52 %, respectively,
compared to the standard device using HTM-1.
Oxidation Response and Coatings for Mo-Si-B Alloys
Authors: Perepezko J. H. , Sakidja R. 
Published: April 2011

ABSTRACTMo-Si-B alloys respond to high temperature oxidation in two distinct stages. First, there is a transient stage with an initial high recession rate that corresponds to the evaporation of volatile MoO3 due to the oxidation of the molybdenum rich phases. The steady state stage of the oxidation begins when a borosilica layer that initiated in the transient period becomes continuous and protects the alloy from further rapid oxidation. Then, the oxidation rate is limited by oxygen diffusion through the borosilicate layer. In order to improve the oxidation performance of the Mo-Si-B alloys, it is necessary to minimize the transient stage. The three phases, Mo (solid solution), Mo3Si (A15) and Mo5SiB2 (T2), composing the Mo-Si-B alloys play different roles in the transient stage. The interaction of the three phases with a reduced microstructure scale can reduce considerably the transient oxidation stage. As a further approach to inhibit the transient stage, a kinetic biasing strategy has been developed to capitalize on the reactions between different phases to develop useful reaction products and alloy compositions that evolve toward a steady state of a compatible system. In order to achieve a compatible interface coating together with enhanced oxidation resistance, a pack cementation process has been adopted to apply diffusion coatings. Two areas are highlighted for successful coating applications on Mo-Si-B alloys and robust high temperature oxidation resistance: development of metal-rich silicide + borosilicide high-temperature coating and in-situ thermal-barrier + borosilica coatings.
The Effect of Ge and Ti Additions on the Microstructures and Properties of Nb-18Si Based Alloys
Authors: Li Zifu , Tsakiropoulos Panos 
Published: April 2011

ABSTRACTThe effects of Ge and Ti additions on the microstructure, hardness and oxidation behaviour of the alloys Nb–18Si–5Ge (ZF1) and Nb–24Ti–18Si–5Ge (ZF3) were studied. The as cast microstructure of the alloy ZF1 consisted of Nbss (cI2), and βNb5Si3 (tI32) with the latter being the primary phase and the two phases forming high volume fractions of Nbss + βNb5Si3 eutectic. The Ge addition stabilised the βNb5Si3 (tI32), and destabilised the Nb3Si (tP32) and the Nbss + Nb3Si eutectic. After heat treatment at 1200 °C for 100 h the βNb5Si3 (tI32) was partially transformed to the αNb5Si3 (tI32), and equilibrium was reached after heat treatment at 1500 °C for 100 h. The phases present in the as cast alloy ZF3 were the Nbss (cI2), and the Nb3Si (tP32), βNb5Si3 (tI32) and Ti5Si3 (hP16) silicides, with the latter forming a eutectic with the solid solution. The same phases were present after heat treatment at 1200 °C for 100 h but only the Nbss, and the Nb3Si and Nb5Si3 silicides were present after 100 h at 1500 °C where TiO2 was also formed. The Ge addition increased the microhardness of the Nb5Si3. The synergy of Ti with Ge resulted in a strong hardening effect and a remarkable retention of the hardness of the alloy ZF3. The additions of Ge and Ti to the Nb-18Si alloy improved the oxidation resistance at 800 °C, but pest oxidation behaviour was not eliminated.
Inkjet-printed PEDOT:PSS/SWCNTs on Paper: Substrate Effects on Conductivity
Authors: Angelo Peter D. , Farnood Ramin R. 
Published: April 2011

ABSTRACTPoly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), or PEDOT:PSS, and single-walled carbon nanotubes (SWCNTs) were incorporated into an inkjet ink. The combination of PEDOT, a conjugated, conductive polymer, and highly conductive CNTs, yielded a conductive film after printing and curing of the ink. Several paper types were used as substrates for depositing printed patterns of the PEDOT:PSS/SWCNT ink. Wide variability in conductivity was observed for different commercial paper types, ranging from a maximum 0.9 S/cm on Epson® Premium Photo cast-coated glossy paper to 3 × 10-5 S/cm on Epson® Premium Presentation coated cardstock. Increasing the SWCNT content of the ink improved conductivity on a non-permeable cellulose acetate substrate to a point, after which the combined effects of ink filtration and jetting limited the number of nanotubes delivered to the substrate. On permeable paper, the irregularity of the substrate overcame the beneficial effects of SWCNTs as “bridges” between conductive PEDOT regions. Correlations between the substrates’ physical structure and conductivity were established for the printed sheets, with densely coated sheets presenting the highest conductivity, and porous sheets the lowest.