| 1. |
- Easterling, K.E., et al.
(författare)
-
On the growth of martensite in steel
- 1980
-
Ingår i: Acta Metallurgica. - : Elsevier BV. - 0001-6160. ; 28:9, s. 1229-1234
-
Tidskriftsartikel (refereegranskat)abstract
- Criteria based on minimum energy and maximum stress considerations have been developed for the first stages of growth of martensite in steel. It is shown that the critical size of nucleus at which dislocation-assisted growth can occur is about 25 nm diameter. The mode of growth governing low carbon lath martensite forming on {111} austenite habit planes is found to be fundamentally different from that of plate martensite which forms on irrational habit planes. A mechanism for lath thickening and growth is advanced in which dislocations nucleate at the thickest section of the lath and then follow after the coherent leading edge of the lath to generate ledges. Plate growth on the other hand can occur by the formation of twins which nucleate and thicken laterally behind the coherent leading edge of the plate.
|
|
| 2. |
- Thölen, A.R., et al.
(författare)
-
Possible wave formation and martensitic transformation of iron particles in copper single crystals during argon ion bombardment
- 1983
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 54:2, s. 1067-1070
-
Tidskriftsartikel (refereegranskat)abstract
- Thin single crystal copper specimens (thickness ~250 nm) containing coherent iron particles (diameter 40-50 nm) have been bombarded with argon ions (5, 80, and 330 keV). During this process some of the iron particles transform to martensite. The transformation was observed near the exposed surface and sometimes also close to the other surface but never in between. This is interpreted in terms of mechanical waves starting from the impact area.
|
|
| 3. |
- Thölén, A.R., et al.
(författare)
-
Strain fields at contacts between small particles
- 2003
-
Ingår i: Journal of Colloid and Interface Science. ; 268:2, s. 368- 370
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Stress fields between interacting small particles (∼100 nm) have been investigated by transmission electron microscopy. The background for these TEM observations is discussed in terms of adhesion stress fields (due to surface forces), the action of an applied point force, possibly magnetic, and dislocations or misfit strains due to an unfavorable matching of crystal lattices at the grain boundary. A further explanation might be sought along the line “squeezed-in oxide” which can be visualized as a coherent particle or a dislocation loop. Accompanying theoretical calculations have been performed and compared with the experimental results.
|
|
| 4. |
- Yao, Yiming, 1957, et al.
(författare)
-
Characterization of Contacting Boundaries between
- 2003
-
Ingår i: Microscopy and Microanalysis. ; 9:03, s. 237-344
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The boundary parameters between contacting spherical bcc-Fe particles have been characterizedwith the Large Angle Convergent Beam Electron Diffraction ~LACBED! technique. The average accuracy ofmeasurements can reach 0.078. The rotation parameters are interpreted using matrix algebra and evaluatedaccording to the CSL model. The deviation between the experimental results and the reference misorientationsgiven in the CSL model is determined. It is possible to reveal preferential misorientations between irregularlyshaped particles with a size less than 100 nm. The method can be applied to nanoparticles and nanocrystallinematerials with a wide range of grain orientations, and it is possible to modify it into an automatic method forTEM measurements.
|
|
| 5. |
- Yao, Yiming, 1957, et al.
(författare)
-
TEM investigation on stress contrast and interfaces of contacting particles, Materials Characterization
- 2000
-
Ingår i: MATERIALS CHARACTERIZATION. ; 44, s. 441-452
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- An investigation on nanoparticle contacting using convergent beam electron diffraction(CBED) and high-resolution electron microscopy (HREM) is reported. Cobalt particles(5–200nm) from a solution-treated Cu–2(w/o)Co alloy were extracted and allowed to contactwithout pressure. The contacting stress field due to adhesion was clearly observed, andthe stress field had a dipole character. Free particles were observed to contact along low-indexzone axes and with specific orientation relationships. Fourier transformation of theHREM micrographs revealed a highly distorted area along the contacting boundary containingdislocations. Electron-diffraction contrast from the stress fields between contactingparticles was simulated, and agreed well with the experiments. © Elsevier Science Inc.,2000. All rights reserved.
|
|
