| 1. |
- Li, C-H., et al.
(författare)
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A lattice resolution study of the martensitic transformation of small iron particles in a copper matrix
- 1985
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Ingår i: Acta Metallurgica. - : Elsevier BV. - 0001-6160. ; 33:2, s. 317-328
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Tidskriftsartikel (refereegranskat)abstract
- The martensitic transformation of small, fully coherent, gamma iron precipitates in an epsilon copper matrix, brought about by the bombardment of thin foils with argon ions, has been studied using lattice fringe imaging. It is found, in general, that only partial transformation of individual particles occurs, this corresponding to a simple homogeneous shear (a Bain strain). In addition, the transformation is limited to particles located within about two particle diameters of the foil surface. It is established that the mere presence of a Frank (or Shockley) loop in a particle, due to the bombardment, is insufficient to trigger the transformation. The implications of this result are discussed with reference to bulk martensite. In the present case, it is concluded that transformation may simply initiate at sites of local decohesion or microslip at the matrix/particle boundaries brought about by vacancy condensation following ion bombardment, these sites being most effective in the vicinity of free surfaces
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| 2. |
- Strid, J., et al.
(författare)
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Microstructure and plasticity of An Al-Al6Fe directionally solidified eutectic alloy
- 1985
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Ingår i: Materials Science and Technology. - : Informa UK Limited. - 0267-0836 .- 1743-2847. ; 1:2, s. 161-166
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Tidskriftsartikel (refereegranskat)abstract
- The microstructure and plasticity of a directionally solidified Al-Al//6Fe eutectic alloy was investigated using quantitative STEM-EDX microanalysis, in situ tensile testing in STEM/SEM, and light/electron optical studies of microstructure before and following drawing and extrusion to wire. It is found that in spite of the brittle nature of the aligned Al//6Fe rods, the alloy as a whole is relatively ductile and can even be drawn or extruded to wire. In the deformed condition the Al//6Fe rods are broken up and the fragmens distributed uniformly throughout the aluminum matrix. The tensile strength and ductility of these drawn wires are good, 400 MN m** minus **2 and 83% area reduction, respectively. Microanalysis studies show that the iron content of the aluminum matrix following solidification is 0. 04 at. %, corresponding to an undercooling of approx. 3 K below the eutectic temperature. The iron content of the matrix can be reduced further by precipitation treatments.
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