| |
Records |
Links |
|
Type |
Current, Michael I.; Wei, Ching-Yeu; Seidman, David N. |
| |
Publication |
Single atom sputtering events: Direct observation of near-surface depleted zones in ion-irradiated tungsten |
Volume |
Journal Article |
Pages |
1981 |
| |
Abstract |
Philosophical Magazine A |
|
| |
Corporate Author |
Phil. Mag. A |
|
Publisher |
43 |
|
Editor |
1 |
| |
Summary Language |
103-138 |
Series Editor |
|
|
Abbreviated Series Title |
The three-drmenslonal spat~al arrangement of vacancies contained in depleted
zones (DZs) of ton-irradiated tungsten speetmena, has been determ~nedw lth atomle
resolution bv the fleld-ion mleroscoue IFIM) tschnmue. These DZs were detected
in the near-suriace reglo* of specimens wh~elh) ad been irradmated rn elfu at $15 K
rvlth 20 keV U+,30 keV W+, Kr+, Cut or Arf ions. T ~vPalu es of t,he ,on dose
were small ($ 10“ 10”s cm-') ; thcreiors, each DZ analysed was tho result
of the impact of a single projcetllo ,on. At the trrad~atlon trmperat~nre (415 K)
both thc self-interstlt~ala toms and vacancies were ~mmob$les. o that the prlmary
state of radiation damage was prescrvcd. The follo\rine propert~esof each UZ were
determined : (I) the total nurnhcr of vacancncs . (9) tlhr nurnbrr 01 vscanc~es xn the
near surfsee region ; (0) tho rpalial sxlcnl-that 8s. tho dlrncns~ons requnred to
determine a volume ; (4) the average vacancy eoncentral~on; ( 5 ) the overage
vacancy concentration assoelaterl w ~ t h the near-surface region : (6) the f~rst.
ncarcat-ne~glnbouor luster d~strlbutmnf or lhc vacanelos rn tlne mar-surface regton ;
(7) the radlal detribution funct~m of all the racanrlrs; (8) tl,c dlstnbutlon of
vacanclcs as a function of depll, normal lo lhe lrrad~atod surface ; and (9) the
sputtering yleld. Most oi the above properklea of the ncar-surfare DZs liad srmllar
Y~IXICtoS t hoso of the DZ$ delected ~nt lre bulk of the Fl5l sprnmcns. Tlre lolsl
numbor of varanc~csdctecler~l n 11,s near-sutiacer egbon was approxnnatelv consistent
r l t h theoretical estimater of Ihc avcrage sputlerctig ymlrl. Thc sputterlrig ylrld of
indtv~dualDZsex~bitesldg nlflcant iluctuat~onfsr om lhe measured average sputtel.ing
yield. |
| |
Series Issue |
|
ISSN |
|
|
Medium |
|
| |
Expedition |
|
Notes |
|
|
Call Number |
|
|
Contribution Id |
|
|
Serial  |
|
URL |
|
ISBN |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
no |
|
NU @ karnesky @ |
|
282 |
| Permanent link to this record |
| |
|
| |
|
Mohamed, Farghalli A.; Langdon, Terence G. |
|
The transition from dislocation climb to viscous glide in creep of solid solution alloys |
|
Journal Article |
|
1974 |
|
Acta Metallurgica |
|
|
|
22 |
|
6 |
|
779-788 |
|
|
|
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. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
no |
|
NU @ karnesky @ |
|
307 |
| Permanent link to this record |
| |
|
| |
|
Li, Yong; Langdon, Terence G. |
|
An Examination of Creep Data for an Al-Mg Composite |
|
Journal Article |
|
1997 |
|
Metallurgical and Materials Transactions A |
|
|
|
28 |
|
|
|
1271-1273 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
no |
|
NU @ karnesky @ |
|
311 |
| Permanent link to this record |
| |
|
| |
|
Hren, John J. |
|
Field-ion microscopy |
|
Book Whole |
|
1968 |
|
|
|
|
|
|
|
|
|
244 |
|
APFIM-shortbib |
|
|
|
|
|
|
|
|
|
Plenum Press |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
no |
|
NU @ karnesky @ |
|
399 |
| Permanent link to this record |
| |
|
| |
|
Akamatsu, Hiroki; Fujinami, Takayoshi; Horita, Zenji; Langdon, Terence G. |
|
Influence of rolling on the superplastic behavior of an Al-Mg-Sc alloy after ECAP |
|
Journal Article |
|
2001 |
|
Scripta Materialia |
|
Scripta Mater. |
|
44 |
|
5 |
|
759-764 |
|
Aluminum alloy; Equal-channel angular pressing; Microstructure; Rolling; Superplasticity |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
no |
|
NU @ karnesky @ |
|
437 |
| Permanent link to this record |
| |
|
| |
|
Cerezo, A.; Godfrey, T. J.; Sijbrandij, S. J.; Smith, G. D. W.; Warren, P. J. |
|
Performance of an energy-compensated three-dimensional atom probe |
|
Journal Article |
|
1998 |
|
Review of Scientific Instruments |
|
Rev. Sci. Instrum. |
|
69 |
|
1 |
|
49-58 |
|
atom probe field ion microscopy |
|
A wide acceptance angle first-order reflectron lens has been incorporated into a three-dimensional atom probe (3DAP) to provide improved mass resolution. This new 3DAP instrument is capable of resolving isotopes in the mass spectrum, with resolutions better than m/Delta m = 500 full width at half maximum and 250 full width at 10% maximum. However, use of a reflectron for energy compensation within an imaging system means that improvements in mass resolution result in degradation of the spatial resolution. This article addresses the detailed design of the energy compensated 3DAP, and the minimization and compensation of chromatic aberrations in the imaging performance of the instrument. Some applications of the new instrument are included to illustrate its capabilities in the atomic-scale analysis of engineering alloys. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
no |
|
NU @ karnesky @ |
|
459 |
| Permanent link to this record |
| |
|
| |
|
Fujita, Takashi; Horita, Zenji; Langdon, Terence G. |
|
Using grain boundary engineering to evaluate the diffusion characteristics in ultrafine-grained Al–Mg and Al–Zn alloys |
|
Journal Article |
|
2004 |
|
Materials Science and Engineering A |
|
Mater. Sci. Eng. A |
|
371 |
|
1-2 |
|
241-250 |
|
Diffusion; Equal-channel angular pressing (ECAP); Grain boundary engineering; Interdiffusion |
|
Samples of dilute Al–Mg and Al–Zn alloys, containing a minor Sc addition, were processed by equal-channel angular pressing (ECAP) to achieve grain refinement and different distributions of the grain boundary misorientations. Diffusion experiments were conducted on fine-grained alloys with either low or high fractions of grain boundaries having high-angle misorientations and on unpressed coarse-grained samples. The diffusion couples were annealed at temperatures from 493 to 848 K and the interdiffusion coefficients were determined from the concentration profiles using the Boltzmann–Matano technique. The results show the interdiffusion coefficients tend to be higher in fine-grained alloys having high fractions of high-angle boundaries than in fine-grained alloys having high fractions of low-angle boundaries. The experimental data are used to estimate values for the grain boundary diffusion coefficients. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
no |
|
NU @ karnesky @ |
|
523 |
| Permanent link to this record |
| |
|
| |
|
Furuno, Kazuko; Akamatsu, Hiroki; Oh-ishi, Keiichiro; Furukawa, Minoru; Horita, Zenji; Langdon, Terence G. |
|
Microstructural development in equal-channel angular pressing using a 60° die |
|
Journal Article |
|
2004 |
|
Acta Materialia |
|
Acta Mater. |
|
52 |
|
9 |
|
2497-2507 |
|
Aluminum; Equal-channel angular pressing; Grain boundary misorientations; Texture; Ultrafine-grained microstructures |
|
Billets of pure aluminum and an Al–1%Mg–0.2%Sc alloy were successfully processed using equal-channel angular pressing (ECAP) with a die having an internal channel angle of 60°. Careful inspection of the microstructures after ECAP revealed excellent agreement, at both the macroscopic and the microscopic levels, with the theoretical predictions for shearing using a 60° die. The grain sizes introduced with the 60° die were slightly smaller than with a conventional 90° die; thus, the values with these two dies were ~1.1 and ~1.2 small mu, Greekm in pure Al and ~0.30 and ~0.36 small mu, Greekm in the Al–Mg–Sc alloy, respectively. Tensile testing of the pure aluminum at room temperature revealed similar strengthening after processing using either a 60° or a 90° die. In tests conducted at 673 K, the Al–Mg–Sc alloy processed with the 60° die exhibited significantly higher elongations to failure due primarily to the larger strain imposed with this die. It is shown using orientation imaging microscopy that superplastic flow in the Al–Mg–Sc alloy produces an essentially random texture and a distribution of boundary misorientations that approximates to the theoretical distribution for an array of randomly oriented grains. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
no |
|
NU @ karnesky @ |
|
530 |
| Permanent link to this record |
| |
|
| |
|
Gómez de Salazar, J. M. ; Barrena, M. I. |
|
Role of Al2O3 particulate reinforcements on precipitation in 7005 Al-matrix composites |
|
Journal Article |
|
2001 |
|
Scripta Materialia |
|
Scripta Mater. |
|
44 |
|
10 |
|
2489-2495 |
|
Aluminum; Composites; Microstructure; Intermetallics phases; TEM |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
no |
|
NU @ karnesky @ |
|
533 |
| Permanent link to this record |
| |
|
| |
|
Han, Bing Q.; Langdon, Terence G. |
|
Factors contributing to creep strengthening in discontinuously-reinforced materials |
|
Journal Article |
|
2002 |
|
Materials Science and Engineering A |
|
Mater. Sci. Eng. A |
|
322 |
|
1-2 |
|
73-78 |
|
Composites; Creep; Load transfer; Substructure strengthening; Threshold stress |
|
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. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
no |
|
NU @ karnesky @ |
|
541 |
| Permanent link to this record |
