1. |
- Borgenstam, Annika, et al.
(författare)
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Determination of the critical carbon content for growth of acicular ferrite
- 2005
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Ingår i: Solid-Solid Phase Transformations in Inorganic Materials 2005, Vol 1. ; , s. 105-110
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Konferensbidrag (refereegranskat)abstract
- The critical carbon content for growth of acicular ferrite has been determined in Fe-Ni-C alloys by using a gradient technique. A carbon gradient has been introduced in binary Fe-Ni alloys which are subsequently heat treated isothermally. The carbon content. at the position where acicular ferrite stops growing, is determined by EMPA (Electron Microprobe Analysis) and microstructural examination with LOM (Light Optical Microscopy). At low Ni contents the experimentally determined values for the critical carbon content can be understood from the hypothesis that the growth of acicular ferrite is controlled by carbon diffusion under paraequilibrium conditions and modified with an extra thermodynamic barrier.
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2. |
- Borgenstam, Annika, et al.
(författare)
-
Metallographic evidence of carbon diffusion in the growth of bainite
- 2009
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 57:11, s. 3242-3252
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Tidskriftsartikel (refereegranskat)abstract
- There are two paradigms regarding the formation of bainite. One is based on the first stage being rapid, diffusionless growth or acicular ferrite and the subsequent formation of carbide occurring by precipitation from the supersaturated ferrite. All assumption that the first stage occurs as a series of subsequent rapid steps resulting in sub-units plays an important role as an explanation of the not so rapid growth observed macroscopically. The other paradigm is based on the first stage being the formation of acicular ferrite under carbon diffusion and on the subsequent growth of carbide and ferrite side by side. Metallographic observations are presented that support the second paradigm. It is difficult to see how they can be accounted for by the first paradigm, in particular the observation of the shapes of sub-units.
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3. |
- Larsson, Henrik, et al.
(författare)
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Trans-interface diffusivity in the Fe-Ni system
- 2007
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Ingår i: Scripta Materialia. - : Elsevier BV. - 1359-6462 .- 1872-8456. ; 56:1, s. 61-64
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Tidskriftsartikel (refereegranskat)abstract
- The trans-interface diffusivity in the Fe-Ni system has been estimated by fitting simulations to experimental data. For diffusion across the alpha/gamma phase boundary, the mobility of species divided by an interfacial thickness of 1 nm, M-k/delta, is approximately 5% of the phase interface mobility M-int at 873 K and 15% at 973 K.
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