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
On the effect of strain on peritectic reactions and transformations in Fe-Ni and Fe-Cu binary alloys
KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processteknologi.
2009 (engelsk)Inngår i: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 22, nr 1-4, s. 232-235Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Differential thermal analysis (DTA) experiments conducted on Fe-Ni and Fe-Cu alloys showed undercooling below the equilibrium peritectic temperatures, T-P. The intervals between the observed liquidus and peritectic temperatures were on average 11 degrees C and 8 degrees C larger than the intervals obtained from equilibrium phase diagrams of Fe-Ni and Fe-Cu respectively. The transformation from delta-Fe to gamma-Fe during the peritectic reaction is associated with density change and strain build up at the delta-Fe/gamma-Fe interface. Thermodynamic calculations showed that by introducing the strain energy at the delta-Fe/gamma-Fe interface, T-P dropped 9 K below its equilibrium value and the increase in the liquidus-to-peritectic temperature interval was in reasonable agreement with the experimental observations. The growth rate of gamma-Fe during a peritectic transformation was calculated based on the strain-induced undercooling in T-P and the results showed partial agreement with observations obtained from CSLM directional solidification experiments conducted earlier on Fe-Ni alloys.

sted, utgiver, år, opplag, sider
2009. Vol. 22, nr 1-4, s. 232-235
Emneord [en]
Peritectic reaction, Interface energy, Strain, Creep, Vacancy
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-10028DOI: 10.1179/136404609X367803ISI: 000268395500057Scopus ID: 2-s2.0-70350783810OAI: oai:DiVA.org:kth-10028DiVA, id: diva2:201453
Merknad
QC 20100803 2nd International Conference on Advances in Solidification Process, Graz, AUSTRIA, JUN 17-20, 2008Tilgjengelig fra: 2009-03-04 Laget: 2009-03-04 Sist oppdatert: 2017-12-13bibliografisk kontrollert
Inngår i avhandling
1. On Peritectic Reactions and Transformations and Hot Forming of Cast Structures
Åpne denne publikasjonen i ny fane eller vindu >>On Peritectic Reactions and Transformations and Hot Forming of Cast Structures
2009 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

This thesis deals with peritectic reactions and transformations that occur during the solidification of many alloys. Peritectics are believed to be a major cause of crack-formation in many steels, thus, good knowledge of the mechanisms by which these phenomena occur is essential for preventing such defects. The thesis also handles the behaviour of metals, in particular cast structures, during hot forming. Grain size and microstructure are of most importance in determining the strength, toughness and performance of a steel. For achieving enhanced mechanical and microstructural properties, good understanding of the phenomena occurring during hot forming is required.

Peritectic reactions and transformations were studied in Fe-base and steel alloys through differential thermal analysis (DTA) experiments and micrographic investigation of quenched DTA samples. The effect of the ferrite/austenite interface strain during the peritectic reaction on equilibrium conditions was thermodynamically analysed, and the results were related to temperature observations from DTA experiments conducted on Fe-base alloys and low-alloy steels. Massive transformations from ferrite to austenite were observed in the micrographs of a number of quenched low-alloy steel samples and it was proposed that these transformations are uncontrolled by diffusion, and occur in the solid state as a visco-plastic stress relief process. DTA study of an austenitic stainless steel indicated that the alloy can exhibit primary precipitations to either ferrite or austenite. A continuously-cast breakout shell of the steel was analyzed and it was suggested that the observed irregularities in growth were due to alternating precipitations of ferrite and austenite; parts of the shell with higher ratios of primary-precipitated ferrite shrink in volume at the peritectic temperature and experience reduced growths.

An experimental method for studying the behaviour of metals during hot forming developed, and hot compression tests were conducted on cast copper and ball-bearing steel samples. Flow stress curves were obtained at varying temperatures and strain rates, and the results showed good agreement with earlier observations reported in literature. Micrographic analysis of quenched samples revealed variations in grain size and a model was fitted to describe the grain size as a function of deformation temperature and strain.

Solidification growth during continuous casting of stainless steel and copper was numerically modelled. A varying heat transfer coefficient was proposed to approximate the experimentally measured growth irregularities in the continuously-cast stainless steel breakout shell. Solidification growth of pure copper was also modelled in the Southwire continuous casting process. Temperature measurements from the chill mould were used to approximate the temperature gradient and the heat extraction from the solidifying strand, and the results were used in a two-dimensional model of solidification.

 

 

sted, utgiver, år, opplag, sider
Stockholm: KTH, 2009. s. 34
Serie
Trita-MG, ISSN 1104-7127 ; 2009:02
Emneord
peritectic reactions, massive transformations, thermal analysis, Fe-base alloys, steels, growth irregularities, hot forming, compression testing, flow stress, grain size.
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-10006 (URN)978-91-7415-242-5 (ISBN)
Disputas
2009-03-27, F3, Lindstedtsvägen 26, KTH, 13:00 (engelsk)
Opponent
Veileder
Merknad
QC 20100803Tilgjengelig fra: 2009-03-04 Laget: 2009-03-02 Sist oppdatert: 2010-08-03bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Andre lenker

Forlagets fulltekstScopus

Søk i DiVA

Av forfatter/redaktør
Nassar, HaniFredriksson, Hasse
Av organisasjonen
I samme tidsskrift
International Journal of Cast Metals Research

Søk utenfor DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric

doi
urn-nbn
Totalt: 95 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