Effect of initial microstructure on superplasticity in ultrafine grained 18Cr-9Ni stainless steel

Toshihiro Tsuchiyma, Yoshikazu Nakamura, Hideyuki Hidaka, Setsuo Takaki

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Ultrafine grained austenitic structure was obtained in 18Cr-9Ni stainless steel by thermomechanical treatment using reversion from deformation-induced martensite. The superplastic deformation behavior was investigated at 923 K for the steels containing various amounts of retained martensite particles in the initial structure before tensile testing. The retained martensite was effective for suppressing grain growth of austenite and necessary for the superplasticity although it was thermodinamically unstable phase and gradually decreased its volume fraction with superplastic deformation. Therefore, the superplastic elongation was strongly dependent on the initial volume fraction of the retained martensite. The total superplastic elongation was enlarged with increasing the initial amount of martensite, and the maximum elongation of about 270% was obtained when the volume fraction was controlled to be around 10 vol%. However, the increase in elongation was leveled off in the range above 15 vol% martensite. The effect of the retained martensite on the superplasticiy was discussed in connection with the changes in volume fraction of the martensite, austenite grain size and deformation mechanism.

Original languageEnglish
Pages (from-to)2259-2263
Number of pages5
JournalMaterials Transactions
Volume45
Issue number7
DOIs
Publication statusPublished - Jan 1 2004

Fingerprint

superplasticity
Superplasticity
Stainless Steel
martensite
Martensite
stainless steels
Stainless steel
microstructure
Microstructure
elongation
Elongation
Volume fraction
Superplastic deformation
austenite
Austenite
thermomechanical treatment
Thermomechanical treatment
Ultrafine
Steel
Tensile testing

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Effect of initial microstructure on superplasticity in ultrafine grained 18Cr-9Ni stainless steel. / Tsuchiyma, Toshihiro; Nakamura, Yoshikazu; Hidaka, Hideyuki; Takaki, Setsuo.

In: Materials Transactions, Vol. 45, No. 7, 01.01.2004, p. 2259-2263.

Research output: Contribution to journalArticle

Tsuchiyma, Toshihiro ; Nakamura, Yoshikazu ; Hidaka, Hideyuki ; Takaki, Setsuo. / Effect of initial microstructure on superplasticity in ultrafine grained 18Cr-9Ni stainless steel. In: Materials Transactions. 2004 ; Vol. 45, No. 7. pp. 2259-2263.
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