Diffusion of Silicon in Iron

Batz, Walter; Mead, H. W.; Birchenall, C. E.

doi:10.1007/bf03397772

Cited by 19 publications

(13 citation statements)

References 1 publication

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“…The unlike next neighbouring of the Fe atoms led the way to the appearance of the ferromagnetic state of this element (6). At 1323 K, the vacancy concentration is high enough to permit a rapid diffusion of Si atoms (7) and enhanced the development of a ferromagnetic C.C. phase.…”

Section: Discussionmentioning

confidence: 99%

Comparative Effects of Thermal Treatments on the Shape Memory Phenomenon of Fe-Mn-Si and Fe-Mn-Cr-Ni-Si Steels

1995

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Two shape-memory steels were water quenched after one hour at 873 K to keep a stable austenitic structure at 298 K. The best values of the shape memory recovery were obtained after a 2.5% strain followed by an annealing at 873 K. In fact, immediately a h r water quenching from 1323K, the Fe-Mu-Si alloy did not present the forward y+s transformation. The transformation was detected after maintaining 48 h. at 298K and was considered as complete after 480 h., using electrical resistivity m'easurements. Samples of the two steels were slowly cooled from 1123 K under vacuum : the Fe-Mn-Si alloy showed completely ordered DO3 + B2 structures and was ferromagnetic whereas the Fe-Mn-Cr-Ni-Si steel was a mixture of the y phase and the DO3 + B2 structures. From previous studies on the Fe-Mn-Si shape memory steel (named F.M.30) the chemical composition was found suitable to consider this alloy as a good model to approach the behaviour of that class of shape memory steels (1,2). To improve corrosion resistance, it was demonstrated that chromium and nickel were essential additions. The influence of some thermal treatments are now studied on the structure and the properties of the two alloys.

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Section: Discussionmentioning

confidence: 99%

Comparative Effects of Thermal Treatments on the Shape Memory Phenomenon of Fe-Mn-Si and Fe-Mn-Cr-Ni-Si Steels

1995

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“…[40] Table III. Composition Ranges of the Selected Experimental Measurements [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] with experimental datapoints of Gro¨bner, [43] Vignes, [44] Bergner and Khaddour, [46] and Fridberg et al [56] The type of experimental diffusion coefficient is defined as i impurity diffusion, c chemical diffusion, and e estimated diffusion.…”

Section: Fig 6-calculatedmentioning

confidence: 99%

Thermodynamic, Kinetic, and Microstructure Data for Modeling Solidification of Fe-Al-Mn-Si-C Alloys

Miettinen

Koskenniska

Visuri

et al. 2020

Metall Mater Trans B

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In this study, a set of thermodynamic, kinetic, and microstructure data is presented to simulate the non-equilibrium solidification of Fe-Al-Mn-Si-C alloys. The data were further validated with the experimental measurements and then used in a thermodynamic–kinetic software, IDS, to establish the effect of the alloying and cooling rate on the solidification behavior of high-AlMnSi (Al ≥ 0.5 wt pct, Mn ≥ 2 wt pct, Si ≥ 1 wt pct) steels. The modeling results were additionally validated by conducting electron probe microanalysis (EPMA) measurements. The results reveal that (1) solidification in high-AlMnSi steels occurs at much lower temperatures than in carbon steels; (2) increasing the cooling rate marginally lowers the solidus; (3) the microsegregation of Mn in austenite is much stronger than that of Si and Al due to the tendency of Al and Si to deplete from the liquid phase; (4) the residual delta ferrite content may be influenced by a proper heat treatment but not to the extent that could be expected solely from thermodynamic calculations; (5) in high-AlMnSi steels containing less than 0.2 wt pct carbon, the cracking tendency related to the strengthening above the solidus and the shell growth below the solidus may be much lower than in carbon steels.

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“…In contrast to carbon diffusion, there has been little to no observed diffusion of Mn and Si, because these elements are substituted and not interstitial like carbon. At a raised temperature of between 1095 and 1347 °C, the diffusion of silicon in iron is described by D = 0.44 * exp(200.83/(R*T)) [22], which results in a diffusion length of max. 4 mm in 1939 days.…”

Section: Change Of Microstructure By Diffusion Processesmentioning

confidence: 99%

Long-term heat treatment of collector bars for aluminium electrolysis: impact on microstructure and electrical properties

et al. 2020

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In order to identify possible optimizations regarding the electrical energy efficiency of an aluminium electrolysis cell, the impact of service temperature on microstructure and electrical properties of the cell cathode was investigated. The investigations include experiments regarding the chemical composition, especially the content of carbon, the electrical conductivity and the microstructure at selected positions. Thermodynamic calculations were used to estimate local service temperatures and explain phase transformations and formations. It was found that due to the increased service temperature diffusion processes of carbon took place to a particular extent between cast iron and collector bar. As a result, the carbon content in the collector bar changed from 0.06 to 1.05–1.4 wt%, while in the cast iron a reduction from 3.47 to < 1.50 wt% took place. These processes led to isothermal phase transformations and formations, that changed the matrix of the collector bar from austenitic with low content of ferrite to an austenitic matrix accompanied by precipitation of secondary, predominantly allotriomorphic cementite at service temperature. It was then shown that this has a negative effect on collector bar and decreases the electrical conductivity by up to 26 %. It was also discovered that graphite spheroidization within the grey cast iron has a positive effect on its electrical conductivity, which has increased by 52 %. The results provide the basis to gain an understanding of the carbon diffusion related processes within the cathode of an electrolysis cell and reveal further potential to increase the energy efficiency of primary aluminium production.

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Diffusion of Silicon in Iron

Cited by 19 publications

References 1 publication

Comparative Effects of Thermal Treatments on the Shape Memory Phenomenon of Fe-Mn-Si and Fe-Mn-Cr-Ni-Si Steels

Comparative Effects of Thermal Treatments on the Shape Memory Phenomenon of Fe-Mn-Si and Fe-Mn-Cr-Ni-Si Steels

Thermodynamic, Kinetic, and Microstructure Data for Modeling Solidification of Fe-Al-Mn-Si-C Alloys

Long-term heat treatment of collector bars for aluminium electrolysis: impact on microstructure and electrical properties

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