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My, Yan; Langdon, Terence G. |
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Creep behavior of an Al-6061 metal matrix composite produced by liquid metallurgy processing |
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Journal Article |
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1997 |
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Abstract |
Materials Science and Engineering A |
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Corporate Author |
Mater. Sci. Eng. A |
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230 |
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1-2 |
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Summary Language |
183-187 |
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Activation energy; Alumina microspheres; Aluminum composite; Creep; Stress exponent; Threshold stress |
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Abbreviated Series Title |
Constant stress creep tests were conducted on an Al-6061 metal matrix composite reinforced with alumina microspheres and produced using liquid metallurgy processing. By introducing a threshold stress into the creep analysis, it is concluded that creep occurs by viscous glide in the matrix with a stress exponent of ≈ 3 and an activation energy of ≈125 kJ mol−1. The threshold stress is probably associated with the presence of fine spinel crystals which have been identified in the matrix of the composite. |
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NU @ karnesky @ |
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715 |
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Gomez de Salazar, J. M.; Barrena, M. I. |
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Dissimilar fusion welding of AA7020/MMC reinforced with Al2O3 particles. Microstructure and mechanical properties |
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Journal Article |
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2003 |
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Materials Science and Engineering A |
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Mater. Sci. Eng. A |
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352 |
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1-2 |
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162-168 |
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Metal matrix composites; Welding; Microstructures; Mechanical testing |
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Metal matrix composites reinforced with Al2O3 particles combine the matrix properties with the ceramic properties of the reinforcement. However, its wide application as structural materials need of the proper development of their joining processes. The present work describes the results obtained from microstructural (Optical and scanning electron microscopy and electron probe microanalyser) and mechanical evaluation (hardness and tensile tests) of aluminum matrix composites (AA7005) reinforced with 10% vol. fraction Al2O3 particles (W7A10), welded to the unreinforced alloy AA7020 (Al–Zn–Mg), using metal inert gas welding process using ER4043 (Al–Si) and ER5356 (Al–Mg) as fillers. The thermal effect of welding on different types of joint results in a loss of the mechanical properties in the heat affected zones. These properties could be recovered with post-welding heat treatments. |
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NU @ karnesky @ |
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268 |
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Zhang, Y.; Blazquez, J.S.; Conde, A.; Warren, P.J.; Cerezo, A. |
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Partitioning of Co during crystallisation of Fe–Co–Nb–B(–Cu) amorphous alloys |
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Journal Article |
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2003 |
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Materials Science and Engineering A |
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Mater. Sci. Eng. A |
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353 |
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1-2 |
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158-163 |
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Amorphous; Soft magnetic; Atom probe; Nanocrystallisation; Microstructure |
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Partitioning behaviour of alloying elements during the primary crystallisation of both Fe18Co60Nb6B16 and Fe39Co39Nb6B15Cu1 alloys has been studied using three-dimensional atom probe (3DAP). Cu rich clusters were found in the Cu-containing alloy, and they provided nucleation sites for the primary α-Fe(Co) particles. In the Cu clusters, concentration of both Fe and Co was greatly decreased. In both Cu-containing and Cu-free alloys Nb and B were depleted in the α-Fe(Co) particles and enriched in the remaining amorphous phase. However, Co concentration in the α-Fe(Co) was the same as the remaining amorphous phase. Based on the 3DAP analysis, the phase volume fraction has been estimated. |
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NU @ karnesky @ |
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818 |
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Han, Bing Q.; Langdon, Terence G. |
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Factors contributing to creep strengthening in discontinuously-reinforced materials |
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Journal Article |
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2002 |
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Materials Science and Engineering A |
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Mater. Sci. Eng. A |
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322 |
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1-2 |
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73-78 |
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Composites; Creep; Load transfer; Substructure strengthening; Threshold stress |
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There have been several experimental investigations of the creep behavior of materials with discontinuous reinforcement. For these materials, logarithmic plots of the steady-state or minimum strain rate against the applied stress usually reveal significant curvature such that the stress exponent, determined from the slope of the line, increases with decreasing stress. Plots of this nature are usually interpreted by invoking a threshold stress, o and replacing the applied stress, , with an effective stress, defined as (−o). This paper examines the implications of this approach using published creep data for several aluminum-based materials. It is shown that the introduction of an effective stress leads to a stress exponent that is similar to that observed in the unreinforced matrix material but, nevertheless, the creep rates in the reinforced materials are often significantly slower than in the matrix. This difference is examined with reference to the occurrence of load transfer and substructure strengthening. |
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NU @ karnesky @ |
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541 |
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Vaumousse, D.; Cerezo, A.; Warren, P. J. |
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A procedure for quantification of precipitate microstructures from three-dimensional atom probe data |
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Journal Article |
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2003 |
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Ultramicroscopy |
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95 |
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215-221 |
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Precipitate quantification; Analytical software method; 3-D atom probe data |
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New analysis software for selecting and quantifying particles in three-dimensional atom maps has been designed. The selection of solute-rich regions is performed by connecting solute atoms which lie within a fixed distance (d), and taking clusters above a certain minimum number of solute atoms (Nmin). Other atoms within some distance L greater than d are taken to belong to the cluster. However, this results in the inclusion of a shell of matrix atoms, which must be removed through an erosion step, to define the final cluster. Data filtered in this way can be used for subsequent quantification of parameters such as size, shape, composition, number density and volume fraction with better accuracy than by manual selection. The choice of d, Nmin and L values is discussed and some methods of evaluation of these parameters are proposed. Examples are presented on the application of this new software to the analysis of early stage clustering in an Al–Mg–Si–Cu alloy and a copper-containing steel. |
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NU @ karnesky @ |
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96 |
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Mohamed, Farghalli A.; Langdon, Terence G. |
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The transition from dislocation climb to viscous glide in creep of solid solution alloys |
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Journal Article |
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1974 |
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Acta Metallurgica |
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22 |
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6 |
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779-788 |
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There are two distinct and separate classes of creep behavior in metallic solid solution alloys. The mechanism of creep in Class I alloys appears to be some form of dislocation climb process, whereas the mechanism in Class II alloys appears to be a viscous glide process. By making assumptions concerning the nature of the climb and glide processes, and using existing experimental results for an Al-3% Mg alloy, it is shown that, to a, first approximation, the criterion for deformation by viscous glide is given by
Image
where B not, vert, similar 8 × 1012, σ is the applied stress, k is Boltzmann's constant, v is Poisson's ratio, γ is the stacking fault energy, G is the shear modulus, b is the Burgers vector, T is the absolute temperature, e is the solute-solvent size difference, and c is the concentration of solute atoms. The creep behavior of twenty-eight different solid solution alloys is analyzed, and it is shown that all alloys except one (Au-10% Ni) give results which are consistent with this criterion for viscous glide. |
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NU @ karnesky @ |
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307 |
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Nie, Zuoren; Jin, Tounan; Fu, Jingbou; Xu, Guefu; Yang, Junjun; Zhou, Jingxia; Zuo, Tieyong |
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Research on Rare Earth in Aluminum |
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Book Chapter |
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2002 |
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Aluminum Alloys 2002: Their Physical and Mechanical Properties |
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1731-1735 |
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Materials Science Forum |
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396-402 |
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NU @ karnesky @ |
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181 |
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Kramer, Lawrence S.; Tack, William T.; Fernandes, Micky T. |
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Scandium in Aluminum Alloys |
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Journal Article |
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1997 |
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Advanced Materials & Processes |
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152 |
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4 |
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23-24 |
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NU @ karnesky @ |
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205 |
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Li, Yong; Langdon, Terence G. |
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An Examination of Creep Data for an Al-Mg Composite |
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Journal Article |
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1997 |
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Metallurgical and Materials Transactions A |
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28 |
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1271-1273 |
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NU @ karnesky @ |
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311 |
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Hunt, Warren H. Jr.; Maruyama, Benji |
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The World Still Won’t Beat a Path to Your Door: Transitioning DRA to the Marketplace |
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Journal Article |
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1999 |
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JOM |
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51 |
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11 |
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62-64 |
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NU @ karnesky @ |
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549 |
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