Change search
ReferencesLink to record
Permanent link

Direct link
Eutectoids with cementite as the major constituent in Fe-C-M alloys
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.ORCID iD: 0000-0002-7656-9733
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
2016 (English)In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 103, 280-289 p.Article in journal (Refereed) PublishedText
Abstract [en]

The addition of a third element to hypereutectoid Fe-C alloys may cause inclusions of a minor constituent in the precipitate of cementite from austenite even if the initial austenite is supersaturated only with cementite. Cementite will often become the major constituent of this kind of microstructure. For Fe-C-Cu alloys this has been explained as the result of precipitation from supersaturated cementite. An alternative mechanism could be that the mixture of cementite and a minor constituent forms by simultaneous and cooperative growth of the two phases, i.e., by a reaction that may be regarded as eutectoid. This mechanism has already been applied to explain the occurrence of eutectoid colonies with cementite as the major constituent and a minor constituent for which there was no supersaturation initially. This phenomenon has been observed in hypereutectoid ternary Fe-C alloys with Al, Mn or Si. The necessary requirements on the ordinary isothermal phase diagram are now examined with a graphical method based on the slopes of tie-lines. It predicts the phenomenon in all cases where it has been observed, including Fe-C-Cu and not in the Fe-C-Ni and Fe-C-Cr systems where it has not been observed. The requirements become more evident when the calculated phase equilibria are plotted as an isothermal phase diagram with the alloy content as a function of the carbon activity instead of carbon content. Finally, a comparison is made with bainite in Fe-C alloys where ferrite is the major and cementite the minor constituent. The same two explanations have been proposed for that case.

Place, publisher, year, edition, pages
Elsevier, 2016. Vol. 103, 280-289 p.
Keyword [en]
Hypereutectoid steels, Cementite precipitate, Cooperative growth, Porous cementite, Orthopearlite, Divergent pearlite, Bainite
National Category
Metallurgy and Metallic Materials
Identifiers
URN: urn:nbn:se:kth:diva-181436DOI: 10.1016/j.actamat.2015.09.008ISI: 000367630500028ScopusID: 2-s2.0-84945305124OAI: oai:DiVA.org:kth-181436DiVA: diva2:900514
Funder
VINNOVA, 2012-02892
Note

QC 20160204. QC 20160205

Available from: 2016-02-04 Created: 2016-02-02 Last updated: 2016-02-05Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Borgenstam, AnnikaHillert, Mats
By organisation
Physical Metallurgy
In the same journal
Acta Materialia
Metallurgy and Metallic Materials

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 42 hits
ReferencesLink to record
Permanent link

Direct link