D.Eylon
,
S.R.Seagle
材料科学技术（英文）
The state of Ti research, development and industry is reviewed in this article. The fifty-year anniversary of Ti technology commercialization in the USA provides an opportunity for a historical perspective. Incorporation of "information-age" tools into alloy development, processing, and production invigorates the technology. Consolidation, diversification and globalization have been transforming the Ti industry in the recent years.
关键词:
Junsheng LU Baorong WU Dept.of Alloy Steel
,
Central Iron and Steel Research Institute Beijing
,
100081
,
ChinaG.J.Wang Dept.of Materials Science and Engineering
,
University of Pennsylvania
,
Philadelphia
,
PA 19104
,
USA
材料科学技术（英文）
The mathematical expressions for magnetomechanical damping capacity are presented by applying Smith-Birchak's model in torsion pendulum and cantilever beam.The peak value ψ_p is found to be related to physical parameters and material constants in the form Kλ_s=αψ_pε_p.which can be used to estimate the magnetostrictive constant λ_s from the damping capacity-strain amplitude curve.A good agreement of experimental data and theoretical prediction was observed in HIDAMETS Cr15A13NiCu.
关键词:
magnetomechanical damping
,
null
,
null
,
null
N.S.Stoloff Department of Materials Engineering
,
Rensselaer Polytechnic Institute
,
Troy
,
New York
,
USAC.T.Liu Metals and Ceramics Division
,
Oak Ridge National Laboratory
,
Oak Ridge
,
Tennessee
,
USA
材料科学技术（英文）
A comprehensive review of low temperature environmental embrittlement in intermetallics is pres- ented. Moisture and hydrogen are shown to severely embrittle many intermetallics, including iron, nickel and titanium aluminides. The roles of composition, microstructure and external test variables are emphasized. Several methods to reduce or avoid embrittlement are described.
关键词:
environmental embrittlement
,
null
,
null
F.M.Chu David P.Pope Dept.of Materials Science and Engineering
,
University of Pennsylvania
,
Philadelphia
,
PA 19104
,
USA
材料科学技术（英文）
In this paper the geometric description and general theory of mechanical twinning are reviewed, the twins in general lattices and superlattices are summarized, and the kinetic process by which mechanical twins form is revisited. A case study of mechanical twinning of HfV2+Nb, (cubic) Laves phase, is presented and the synchroshear of selected atomic layers is proposed to explain the physical process of twin formation. If the twins form in this way, then long shear vectors and / or atomicshuffles are not really necessary.
关键词:
twin
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null
,
null
,
null
R.Gibala H.Chang C.M.Czarnik K.M.Edwards A.Misra Department of Materials Science and Engineering
,
University of Michigan
,
Ann Arbor
,
Michigan 48109-2136
,
USA
材料科学技术（英文）
This paper demonstrates that plasticity enhancement processes previously observed in bcc metals and associated with the presence of surface films and precipitates or dispersoids are operative in or- dered intermetallic compounds.' Some specific results are given for NiAl-and MoSi_2-based materials.The plasticity of NiAl and related B2 ordered alloys at room temperature during monotonic deformation can be enhanced by application of surface films such as electroless nickel platings.Sig- nificant effects are also observed during cyclic deformation.The presence of ductile second phases such as fcc γ or the ordered phase γ' introduced by alloying also enhances the plasticity of NiAl. MoSi_2 exhibits similar effects of surface films and second phases,but primarily at elevated tempera- tures,T>900℃.In this paper,we illustrate the effects of ZrO_2 surface films deposited near room temperature and TiC particulate additions introduced by powder processing techniques.In all cases, the plasticity enhancement is associated with enhanced dislocation generation processes under the conditions of constrained deformation at the film-substrate or precipitate/dispersoid-matrix inter- face of the composite system.
关键词:
plasticity
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null
,
null
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null
Corrosion Reviews
The corrosion field experienced a rapid growth in knowledge and innovations in the last decade. In this paper, a bibliometric analysis was applied to evaluate the global scientific production of corrosion papers (46,384 pieces) front 1992 to 2007 in all journals of all the subject categories of the Science Citation Index Expanded (SCIE) compiled by the Institute for Scientific Information (ISI), Philadelphia, USA. The analysis of the published Outputs showed that research on corrosion increased steadily over the past 16 years and the researchers from the EU, the USA and China contributed greatly to the rise in publications. Synthetically analyzing the information including international cooperation, subject category, distribution Of journals, document type, document language and author keywords, the development of corrosion research over the past 16 years has been visualized and several key findings were provided. This bibliometric method can help relevant researchers realize the panorama of global corrosion research, and establish the further research direction.
关键词:
Corrosion;Bibliometrics;Research trends
Journal of Solid State Chemistry
A new compound, beta-SrGaBO4, has been attained through solid phase transition from alpha-SrGaBO4 at high temperatures. Its crystal structure has been determined from powder X-ray diffraction data by direct methods. The refinement was carried out using the Rietveld method and the final refinement converged with Rp = 11.42 % and Rwp = 15.16 %. It has an orthorhombic P2(1)2(1)2 space group with cell parameters a = 15.3706(2) Angstrom b = 8.992 1 (1) Angstrom, c = 5.919 1 (1) A, and Z = 8. The structure of beta-SrGaBO4 is built up from Ga2BO8 units formed by two GaO4 tetrahedra and one BO3 triangle, and Sr2O12 units formed by two SrO7 groups. Tetrahedra [GaO4] are linked by shared O(3) and O(7) atoms to form infinite chains along the e axis. (C) 2002 Elsevier Science, (USA).
关键词:
beta-SrGaBO4;borate;structure determination;X-ray powder diffraction;crystal-structure
Composites Science and Technology
The thermal expansion of the reference sample, pure copper film in the temperature range of - 120 to 200 degrees C was first measured using the newly improved CCD imaging technique for measurement of thermal expansion of thin films. The results showed good accordance with the recommended data given by TPRC (Thermophysical Properties Research Centre, USA) handbook, verifying that the present method is valid for measuring thermal expansion of films. Then, the thermal expansion TE (Delta L/L-0) of silica/polyimide composite films with different SiO2 fractions i.e. 0, 1, 3, 5, 8, 10 and 15 wt% prepared using the sol-gel technique was obtained in the temperature range of - 120 to 200 degrees C using the newly improved CCD method and the differential coefficient thermal expansion (CTE) can be deduced by Delta L/L-0 similar to temperature relation. The CTE Of SiO2/PI Composite films decreased with the increase Of SiO2 content and the decrease of temperature. An empirical equation of CTE of SiO2/PI with SiO2, content has been given in this paper. (C) 2007 Elsevier Ltd. All rights reserved.
关键词:
silica/polyimide composite film;thermal expansion;CCD imaging;technique;low temperature;elevated temperature;mechanical-properties;cryogenic properties;nanocomposite films;polyimide films;low-temperature;silica
