In situ XRD study of the graphite surface layer formation during thermal cycling of cast iron

F. M. Braz Fernandas; Rui J. C. Silva; Angela Gomes

In situ XRD study of the graphite surface layer formation during thermal cycling of cast iron

F. M. Braz Fernandas, Rui J. C. Silva, Angela Gomes

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

Abstract

During service, parts made of spheroidal graphite (SG) cast iron may be submitted to temperature cycling. It is experimentally known that the growth of graphite can not be explained by the volume diffusion of carbon. Recent results obtained for the desaturation of the austenite in a SG cast iron confirmed the existence of a significant difference between the experiment and the theoretical predictions based on the volume diffusion of carbon. According to stress state calculations, one possible explanation for this discrepancy could rely on the existence of a strong hydrostatic component gradient close to the austenite / graphite interface that would act as a barrier for the carbon diffusion across this interface. However, this discrepancy seems not to be present in the case of the carbon diffusion to the free surface of the material when cycled under vacuum. In situ high temperature XRD has been used to follow the growth of the graphite layers on the free surface of the samples during cycling between 800 and 950°C. The results of these XRD tests are compared to previous results concerning the volume diffusion of carbon during graphitization.

Original language	English
Title of host publication	Advanced Materials Forum II: Proceedings of the II International Materials Symposium: Materials 2003 and XI Encontro da Sociedade Portuguesa de Materiais, 2003 ATERIAIS
Editors	R. Martins, E. Fortunato, I. Ferreira, C. Dias
Publisher	Trans Tech Publications
Pages	326-329
Number of pages	4
Publication status	Published - 29 Jul 2004
Event	Advanced Materials Forum II: Proceedings of the II International Materials Symposium: Materials 2003 and XI Encontro da Sociedade Portugesa de Materials, 2003 ATERIAIS - Caparica, Portugal Duration: 14 Apr 2003 → 16 Apr 2003

Publication series

Name	Materials Science Forum
Publisher	Trans Tech Publications Ltd
Volume	455-456
ISSN (Print)	0255-5476

Conference

Conference	Advanced Materials Forum II: Proceedings of the II International Materials Symposium: Materials 2003 and XI Encontro da Sociedade Portugesa de Materials, 2003 ATERIAIS
Country/Territory	Portugal
City	Caparica
Period	14/04/03 → 16/04/03

Keywords

Cast iron
Graphitization
Metals characterization
X-ray diffraction

Cite this

Fernandas, F. M. B., Silva, R. J. C., & Gomes, A. (2004). In situ XRD study of the graphite surface layer formation during thermal cycling of cast iron. In R. Martins, E. Fortunato, I. Ferreira, & C. Dias (Eds.), Advanced Materials Forum II: Proceedings of the II International Materials Symposium: Materials 2003 and XI Encontro da Sociedade Portuguesa de Materiais, 2003 ATERIAIS (pp. 326-329). (Materials Science Forum; Vol. 455-456). Trans Tech Publications.

Fernandas, F. M. Braz ; Silva, Rui J. C. ; Gomes, Angela. / In situ XRD study of the graphite surface layer formation during thermal cycling of cast iron. Advanced Materials Forum II: Proceedings of the II International Materials Symposium: Materials 2003 and XI Encontro da Sociedade Portuguesa de Materiais, 2003 ATERIAIS. editor / R. Martins ; E. Fortunato ; I. Ferreira ; C. Dias. Trans Tech Publications, 2004. pp. 326-329 (Materials Science Forum).

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title = "In situ XRD study of the graphite surface layer formation during thermal cycling of cast iron",

abstract = "During service, parts made of spheroidal graphite (SG) cast iron may be submitted to temperature cycling. It is experimentally known that the growth of graphite can not be explained by the volume diffusion of carbon. Recent results obtained for the desaturation of the austenite in a SG cast iron confirmed the existence of a significant difference between the experiment and the theoretical predictions based on the volume diffusion of carbon. According to stress state calculations, one possible explanation for this discrepancy could rely on the existence of a strong hydrostatic component gradient close to the austenite / graphite interface that would act as a barrier for the carbon diffusion across this interface. However, this discrepancy seems not to be present in the case of the carbon diffusion to the free surface of the material when cycled under vacuum. In situ high temperature XRD has been used to follow the growth of the graphite layers on the free surface of the samples during cycling between 800 and 950°C. The results of these XRD tests are compared to previous results concerning the volume diffusion of carbon during graphitization.",

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Fernandas, FMB , Silva, RJC & Gomes, A 2004, In situ XRD study of the graphite surface layer formation during thermal cycling of cast iron. in R Martins, E Fortunato, I Ferreira & C Dias (eds), Advanced Materials Forum II: Proceedings of the II International Materials Symposium: Materials 2003 and XI Encontro da Sociedade Portuguesa de Materiais, 2003 ATERIAIS. Materials Science Forum, vol. 455-456, Trans Tech Publications, pp. 326-329, Advanced Materials Forum II: Proceedings of the II International Materials Symposium: Materials 2003 and XI Encontro da Sociedade Portugesa de Materials, 2003 ATERIAIS, Caparica, Portugal, 14/04/03.

In situ XRD study of the graphite surface layer formation during thermal cycling of cast iron. / Fernandas, F. M. Braz ; Silva, Rui J. C.; Gomes, Angela.
Advanced Materials Forum II: Proceedings of the II International Materials Symposium: Materials 2003 and XI Encontro da Sociedade Portuguesa de Materiais, 2003 ATERIAIS. ed. / R. Martins; E. Fortunato; I. Ferreira; C. Dias. Trans Tech Publications, 2004. p. 326-329 (Materials Science Forum; Vol. 455-456).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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N2 - During service, parts made of spheroidal graphite (SG) cast iron may be submitted to temperature cycling. It is experimentally known that the growth of graphite can not be explained by the volume diffusion of carbon. Recent results obtained for the desaturation of the austenite in a SG cast iron confirmed the existence of a significant difference between the experiment and the theoretical predictions based on the volume diffusion of carbon. According to stress state calculations, one possible explanation for this discrepancy could rely on the existence of a strong hydrostatic component gradient close to the austenite / graphite interface that would act as a barrier for the carbon diffusion across this interface. However, this discrepancy seems not to be present in the case of the carbon diffusion to the free surface of the material when cycled under vacuum. In situ high temperature XRD has been used to follow the growth of the graphite layers on the free surface of the samples during cycling between 800 and 950°C. The results of these XRD tests are compared to previous results concerning the volume diffusion of carbon during graphitization.

AB - During service, parts made of spheroidal graphite (SG) cast iron may be submitted to temperature cycling. It is experimentally known that the growth of graphite can not be explained by the volume diffusion of carbon. Recent results obtained for the desaturation of the austenite in a SG cast iron confirmed the existence of a significant difference between the experiment and the theoretical predictions based on the volume diffusion of carbon. According to stress state calculations, one possible explanation for this discrepancy could rely on the existence of a strong hydrostatic component gradient close to the austenite / graphite interface that would act as a barrier for the carbon diffusion across this interface. However, this discrepancy seems not to be present in the case of the carbon diffusion to the free surface of the material when cycled under vacuum. In situ high temperature XRD has been used to follow the growth of the graphite layers on the free surface of the samples during cycling between 800 and 950°C. The results of these XRD tests are compared to previous results concerning the volume diffusion of carbon during graphitization.

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ER -

Fernandas FMB , Silva RJC, Gomes A. In situ XRD study of the graphite surface layer formation during thermal cycling of cast iron. In Martins R, Fortunato E, Ferreira I, Dias C, editors, Advanced Materials Forum II: Proceedings of the II International Materials Symposium: Materials 2003 and XI Encontro da Sociedade Portuguesa de Materiais, 2003 ATERIAIS. Trans Tech Publications. 2004. p. 326-329. (Materials Science Forum).

In situ XRD study of the graphite surface layer formation during thermal cycling of cast iron

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