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Type Han, B.Q.; Lee, Z.; Witkin, D.; Nutt, S.; Lavernia, E.J.
  Publication Deformation behavior of bimodal nanostructured 5083 Al alloys Volume Journal Article
Pages 2005
  Abstract Metallurgical And Materials Transactions A-Physical Metallurgy And Materials Science  
  Corporate Author Metall. Mater. Trans. A-Phys. Metall. Mater. Sci.  
Publisher 36a  
Editor (up) 4
  Summary Language 957-965 Series Editor  
Abbreviated Series Title Cryomilled 5083 At alloys blended with volume fractions of 15, 30, and 50 pct unmilled 5083 At were produced by consolidation of a mixture of cryomilled 5083 At and Unmilled 5083 A] powders. A bimodal grain size was achieved in the as-extruded alloys in which nanostructured regions had a grain size of 200 nm and coarse-grained regions had a grain size of I µm. Compression loading in the longitudinal direction resulted in elastic-perfectly plastic deformation behavior. An enhanced tensile elongation associated with the occurrence of a Luders band was observed in the bimodal alloys. As the volume fraction of coarse grains was increased, tensile ductility increased and strength decreased. Enhanced tensile ductility was attributed to the occurrence of crack bridging as well as delamination between nanostructured and coarse-grained regions during plastic deformation.
  Series Issue Univ Calif Davis, Dept Chem Engn & Mat Sci, Davis, CA 95616 USA, Email: bqhan@ucdavis.edu ISSN  
Medium
  Expedition Minerals Metals Materials Soc Notes  
Call Number  
Contribution Id English  
Serial URL ISBN  
1073-5623 ISI:000227914900007 no NU @ karnesky @ 10025
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Park, J.H.; Lee, Y.S.; Nam, W.J.; Park, K.T. Comparison of compressive deformation of ultrafine-grained 5083 Al alloy at 77 and 298 K Journal Article 2005 Metallurgical And Materials Transactions A-Physical Metallurgy And Materials Science Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. 36a 5 1365-1368 The compression behaviors of well-annealed coarse-grained (CG) and ultrafine-grained (UFG) 5083 Al alloys at 77 and 298 K were compared. For the CG alloy, stage II and III strain hardening were dominant at 77 and 298 K, respectively, depending on the completeness of dislocation cell formation. The UFG alloy exhibited the elastic-near perfectly plastic behavior without distinctive dislocation cell formation at both temperatures. For both alloys, the flow stress at 77 K was much higher than that at 298 K. Hanbat Natl Univ, Div Adv Mat Sci & Engn, Taejon 305719, South Korea, Email: ktpark@hanbat.ac.kr Minerals Metals Materials Soc English 1073-5623 ISI:000228797500029 no NU @ karnesky @ 10027
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Galtrey, M.J.; Oliver, R.A.; Kappers, M.J.; McAleese, C.; Zhu, D.; Humphreys, C.J.; Clifton, P.H.; Larson, D.; Cerezo, A. Compositional inhomogeneity of a high-efficiency In[sub x]Ga[sub 1 - x]N based multiple quantum well ultraviolet emitter studied by three dimensional atom probe Journal Article 2008 Applied Physics Letters Appl. Phys. Lett. 92 4 041904-3 III-V semiconductors; indium compounds; light emitting diodes; semiconductor quantum wells; wide band gap semiconductors An InxGa1−xN based multiple quantum well structure emitting in the ultraviolet, which has the highest reported efficiency (67%) at its wavelength (380 nm), was analyzed with the three-dimensional atom probe. The results reveal gross discontinuities and compositional variations within the quantum well layers on a 20100 nm length scale. In addition, the analysis shows the presence of indium in the AlyGa1−yN barrier layers, albeit at a very low level. By comparing with analogous epilayer samples, we suggest that the quantum well discontinuities we observe may play an important role in improving the efficiency of these structures. Aip no NU @ karnesky @ 10199
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Radmilovic, V.; Tolley, A.; Marquis, E.A.; Rossell, M.D.; Lee, Z.; Dahmen, U. Monodisperse Al3(LiScZr) core/shell precipitates in Al alloys Journal Article 2008 Scripta Materialia 58 7 529-532 Al alloy; Atom probe tomography (APT); Core/shell precipitates; Dispersion strengthening; Electron microscopy We demonstrate a way of producing monodisperse Al3(LiScZr) core/shell inclusions using solid-state reactions. A uniform distribution of particles with a Li- and Sc-rich core surrounded by Li-rich shell a few nanometers thick with Zr segregating at the core/shell interface can be made reproducibly by exploiting kinetic and thermodynamic parameters. This approach to generating precipitate distributions can be applied to a range of alloys and could lead to new types of dispersion-strengthened materials. no NU @ karnesky @ 13381 10202
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Lee, S.-M.; Pyun, S.-I. Effects of hydrogen redistribution on hydrogen-assisted cracking in Al-1.9% Li and Al-4.5% Zn-2.3% Mg alloys Journal Article 1990 Scripta Metallurgica et Materialia 24 9 1629-1634 no NU @ karnesky @ 10238
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Lee, D.-H.; Hong, K.T.; Nam, S.W. Intergraular fracture behavior of an Al-3at.%Mg solid solution alloy under the viscous glide creep condition Journal Article 1991 Scripta Metallurgica et Materialia 25 4 823-828 no NU @ karnesky @ 10279
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Lee, Z.; Witkin, D.B.; Radmilovic, V.; Lavernia, E.J.; Nutt, S.R. Bimodal microstructure and deformation of cryomilled bulk nanocrystalline Al-7.5Mg alloy Journal Article 2005 Materials Science and Engineering: A The Langdon Symposium: Flow and forming of Crystalline Materials 410-411 462-467 Nanocrystalline; Bimodal; Cryomilling; Aluminum; Deformation The microstructure, mechanical properties and deformation response of bimodal structured nanocrystalline Al-7.5Mg alloy were investigated. Grain refinement was achieved by cryomilling of atomized Al-7.5Mg powders, and then cryomilled nanocrystalline powders blended with 15 and 30% unmilled coarse-grained powders were consolidated by hot isostatic pressing followed by extrusion to produce bulk nanocrystalline alloys. Bimodal bulk nanocrystalline Al-7.5Mg alloys, which were comprised of nanocrystalline grains separated by coarse-grain regions, show balanced mechanical properties of enhanced yield and ultimate strength and reasonable ductility and toughness compared to comparable conventional alloys and nanocrystalline metals. The investigation of tensile and hardness test suggests unusual deformation mechanisms and interactions between ductile coarse-grain bands and nanocrystalline regions. no NU @ karnesky @ 10321
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Witkin, D.; Lee, Z.; Rodriguez, R.; Nutt, S.; Lavernia, E. Al-Mg alloy engineered with bimodal grain size for high strength and increased ductility Journal Article 2003 Scripta Materialia 49 4 297-302 Aluminum alloys; Nanocrystalline materials; Mechanical properties Al-7.5Mg powders were cryomilled, then consolidated and extruded to produce bulk nanostructured material. The extrusions had a tensile yield strength of 641 MPa and an ultimate strength of 847 MPa. Additional samples were prepared by combining cryomilled powder unmilled Al-7.5Mg, resulting in extrusions with high strength and increased ductility. no NU @ karnesky @ 10322
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Ye, J.; Han, B.Q.; Lee, Z.; Ahn, B.; Nutt, S.R.; Schoenung, J.M. A tri-modal aluminum based composite with super-high strength Journal Article 2005 Scripta Materialia 53 5 481-486 Metal matrix composites; Aluminum alloy; Cryomilling; Compression test; Nanocrystalline A bulk composite with 10 wt.% B4C, 50 wt.% coarse-grained 5083 Al and the balance nanocrystalline 5083 Al was fabricated, using cryomilling and compaction. This tri-modal composite exhibited an extremely high yield strength (up to 1065 MPa) when tested under compressive load. The structure-property relationships are discussed. no NU @ karnesky @ 10328
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Veerababu, R.; Balamuralikrishnan, R.; Muraleedharan, K.; Srinivas, M. Three-dimensional atom probe investigation of microstructural evolution during tempering of an ultra-high-strength high-toughness steel Journal Article 2008 Metallurgical And Materials Transactions A-Physical Metallurgy And Materials Science Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. 39a 7 1486-1495 The evaluation of the tempering response of an ultra-high-strength, high-toughness (UHSHT) steel revealed that samples austenitized at 900 degrees C and tempered for 4 and 8 hours at 485 degrees C had similar yield strengths but a similar to 50 pct increase in fracture toughness for the 8-hour temper. The results of our investigations of microstructural origins of this difference, using the nanometric scale resolution of the three-dimensional atom probe (3DAP) suggest that nanoscale strengthening precipitates, essentially carbides and intermetallic clusters (containing primarily Cr and Mo atoms), are present in both samples. The chemical compositions of the particles in the two samples were found to be similar, but clear evidence of differences in physical attributes of the precipitates, such as particle size, morphology, and interparticle spacing, are seen. Def Met Res Lab, Hyderabad 500058, Andhra Pradesh, India, Email: muraleek@hotmail.com Springer English 1073-5623 ISI:000256081500004 no NU @ m-krug @ 10377
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