Modelling and simulation of carbides in alpha-Fe alloys from first principles: alloying elements, diffusion and nucleation
Description
Low alloys steels are mainly made of iron and carbon, with additional alloying elements in low quantities. In these materials, secondary phases enriched in carbon - namely carbides - can appear. The formation of carbides can drastically change mechanical properties of steels. It may for example promote the appearance of cracks. In particular, the presence of carbides in ferritic steels used in the nuclear industry can raise some safety concerns. Cementite (Fe3C) and the Mo2C molybdenum carbide are two very common carbides in steels. The goal of this thesis is to investigate properties of these two carbides via modelling and computer simulations. Various methods are useful to investigate atomic-scale properties that are difficult to access experimentally. This way, we studied carbon diffusion in cementite and compared with indirect experimental data. We also quantified effects of alloying elements on cementite and Mo2C properties. Comparisons are made with experimental data available at this time. In addition, we developed a modelling approach in order to investigate the precipitation of cementite. (author)
Abstract (French)
Les aciers faiblement allies sont principalement constitues de fer et de carbone, avec quelques elements d'alliage supplementaires en faible quantite. Dans ces materiaux, des phases secondaires enrichies en carbone - des carbures - peuvent apparaitre. La formation de carbures peut modifier radicalement les proprietes mecaniques des aciers. Elle peut par exemple favoriser l'apparition de fissures. En particulier, la presence de certains carbures dans les aciers ferritiques utilises dans l'industrie nucleaire pourrait conduire a leur fragilisation. La cementite (Fe3C) et le carbure de molybdene Mo2C sont deux carbures frequents dans les aciers. L'objectif de cette these est d'etudier les proprietes de ces deux carbures en utilisant la modelisation et des simulations numeriques. Ces methodes permettent d'aborder des donnees inaccessibles experimentalement. Ainsi, nous avons etudie la diffusion du carbone dans la cementite et compare nos resultats avec des donnees experimentales indirectes. Nous avons egalement quantifie les effets des elements d'alliage sur les proprietes de la cementite et du Mo2C. De plus, nous avons developpe une strategie de modelisation afin d'etudier la precipitation de la cementite. (auteur)
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Additional details
Additional titles
- Original title (English)
- Modelisation des proprietes des carbures dans les alliages de fer-alpha a partir de premiers principes: elements d'alliage, diffusion et germination
Publishing Information
- Imprint Pagination
- 129 p.
- Report number
- FRCEA-TH--13846
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 53029555
- Subject category
- S36: MATERIALS SCIENCE;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- CARBON; CEMENTITE; COMPUTERIZED SIMULATION; CRACKS; DIFFUSION; LOW ALLOY STEELS; MECHANICAL PROPERTIES; MOLYBDENUM CARBIDES; PRECIPITATION
- Descriptors DEC
- ALLOYS; CARBIDES; CARBON ADDITIONS; CARBON COMPOUNDS; ELEMENTS; INTERMETALLIC COMPOUNDS; IRON ALLOYS; IRON BASE ALLOYS; IRON CARBIDES; IRON COMPOUNDS; MOLYBDENUM COMPOUNDS; NONMETALS; REFRACTORY METAL COMPOUNDS; SEPARATION PROCESSES; SIMULATION; STEELS; TRANSITION ELEMENT ALLOYS; TRANSITION ELEMENT COMPOUNDS
Optional Information
- Notes
- 221 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses