Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Study of precipitation in martensitic Fe-C-Cr alloys during tempering: Experiments and modelling
KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Metallografi.ORCID-id: 0000-0003-4825-7430
2015 (engelsk)Licentiatavhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Understanding the precipitation reaction is very important since precipitation hardening is one of the most effective strengthening mechanisms in metallic alloys. In martensitic steels, a tempering heat treatment is often performed. During tempering various new phases are precipitated and the spatial and temporal evolution of these precipitates strongly influences the properties of the steel, such as strength/ductility, creep, fatigue and hot corrosion resistance. Therefore, the possibility of quantitative modelling of the precipitation process will provide many opportunities for advanced materials and process design and optimization as well as service life assessments. The Fe-C-Cr system forms the basis for tool steels and is consequently used in many applications such as e.g. metal forming operations. They are characterized by a high hardness and good toughness, even at elevated temperatures.In the present work, the as-quenched martensitic microstructures of four Fe-C-Cr alloys with varying Cr and C contents were characterized by Light Optical Microscopy (LOM) and Electron Microscopy. The effects of Cr and C on the morphology of martensite were investigated. It was found that Cr addition had a similar effect as C on the martensitic morphology and on the ratio of high-angle grain boundary (HAGB) to low-angle grain boundary (LAGB). However, the micro-hardness was unaffected by the Cr addition whilst it was strongly influenced by the C addition.In addition, a quantitative experimental characterization of the precipitates formed during tempering of the martensite was performed. The Langer-Schwartz theory combined with the Kampmann-Wagner-Numerical (KWN) method, as implemented in the software TC-PRISMA, was used to predict the precipitation of carbides after tempering in one of the model alloys: Fe-0.15C-4.0Cr (mass%). The microstructure characterization of the as-quenched material provided vital input parameters for the modelling work and a comparison was made between the modelling predictions and the experimental results. The effect of parameters such as dislocation density, grain size and interfacial energy on the precipitation of carbides was discussed.

sted, utgiver, år, opplag, sider
Stockholm: KTH Royal Institute of Technology, 2015. , s. xi, 34
Emneord [en]
Fe-C-Cr alloy, Microstructure, Precipitates, Tempering of martensite, Electron microscopy, Modelling.
HSV kategori
Forskningsprogram
Teknisk materialvetenskap
Identifikatorer
URN: urn:nbn:se:kth:diva-176430ISBN: 978-91-7595-756-2 (tryckt)OAI: oai:DiVA.org:kth-176430DiVA, id: diva2:866846
Presentation
2015-12-04, Kuben N111, Brinellvägen 23, Stockholm, 13:00 (engelsk)
Opponent
Veileder
Merknad

QC 20151105

Tilgjengelig fra: 2015-11-05 Laget: 2015-11-03 Sist oppdatert: 2015-11-10bibliografisk kontrollert
Delarbeid
1. Microstructure of Martensite in Fe-C-Cr and its Implications for Modelling of Carbide Precipitation during Tempering
Åpne denne publikasjonen i ny fane eller vindu >>Microstructure of Martensite in Fe-C-Cr and its Implications for Modelling of Carbide Precipitation during Tempering
Vise andre…
2014 (engelsk)Inngår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 54, nr 11, s. 2649-2656Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The microstructure of as-quenched martensite in four Fe-C-Cr alloys (0.15C-1Cr, 0.15C-4Cr, 1C-1Cr, 1C-4Cr, mass%) has been investigated. Moreover, the microstructures served as input for setting up modeling of carbide precipitation during tempering of martensite. The modelling was conducted using the Langer-Schwartz approach and the software TC-PRISMA, which retrieves thermodynamic data from the Thermo-Calc databank. It was found that the martensite in the low carbon steels is predominantly lath martensite with units arranged parallel to each other. On the other hand, the plate martensite dominates the microstructure in the high carbon steels. The ratio of high-angle to low-angle grain boundaries was found to increase with increasing Cr in the low carbon steels, which indicates that Cr has a similar effect as C on the lath martensite microstructure, however, the micro-hardness remained unaffected by the addition of Cr. Finally, the precipitation modeling clearly demonstrates the importance of proper definition of the initial microstructure for predictive modelling. Parameters such as dislocation density and frequency of high-angle grain boundaries have a drastic effect on e.g. the mean size of carbides.

Emneord
steels, martensite, microstructure, precipitation, electron microscopy, modeling
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-158349 (URN)10.2355/isijinternational.54.2649 (DOI)000345485100030 ()2-s2.0-84917739189 (Scopus ID)
Merknad

QC 20150121

Tilgjengelig fra: 2015-01-21 Laget: 2015-01-07 Sist oppdatert: 2018-08-21bibliografisk kontrollert
2. Quantitative modeling and experimental verification of carbide precipitation in a martesnsitic Fe-0,16 wt.%C-4.0 wt.%Cr alloy
Åpne denne publikasjonen i ny fane eller vindu >>Quantitative modeling and experimental verification of carbide precipitation in a martesnsitic Fe-0,16 wt.%C-4.0 wt.%Cr alloy
Vise andre…
(engelsk)Manuskript (preprint) (Annet vitenskapelig)
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-176470 (URN)
Merknad

QS 2015

Tilgjengelig fra: 2015-11-05 Laget: 2015-11-05 Sist oppdatert: 2015-11-10bibliografisk kontrollert

Open Access i DiVA

Thesis(1926 kB)783 nedlastinger
Filinformasjon
Fil FULLTEXT01.pdfFilstørrelse 1926 kBChecksum SHA-512
628f748acce32a7df03c3d1f51c7ddcb6bc97a6e40e3081c937b944d7db0e99e56bf528ca9870e3ec38a427b75bbb28d0eb64009497a6048df005259dd79036e
Type fulltextMimetype application/pdf

Personposter BETA

Hou, Ziyong

Søk i DiVA

Av forfatter/redaktør
Hou, Ziyong
Av organisasjonen

Søk utenfor DiVA

GoogleGoogle Scholar
Totalt: 783 nedlastinger
Antall nedlastinger er summen av alle nedlastinger av alle fulltekster. Det kan for eksempel være tidligere versjoner som er ikke lenger tilgjengelige

isbn
urn-nbn

Altmetric

isbn
urn-nbn
Totalt: 865 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf