Aging effects on the cyclic deformation mechanisms of a duplex stainless steel

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(96)00045-6· OSTI ID:415394

Llanes, L; Mateo, A; Iturgoyen, L; Anglada, M ^[1]

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1. Univ. Politecnica de Catalunya, Barcelona (Spain). Dept. de Ciencia de los Materiales e Ingenieria Metalurgica

Aging effects on the cyclic deformation mechanisms of an AISI-329 duplex stainless steel have been studied on the basis of the cyclic hardening-softening response, cyclic stress-strain curve and substructure evolution within the individual phases. The cyclic behavior of an unaged and two aged materials shows, in terms of plastic strain amplitude ({var_epsilon}{sub pl}), three well-defined stages. In the first regime, at low {var_epsilon}{sub pl}, no differences are observed among the response of the three materials as a consequence of the dominance of austenitic-like deformation mechanisms for all the materials. In the second regime, at intermediate {var_epsilon}{sub pl}, the cyclic behavior of unaged material is associated with a mixed austenitic/ferritic-like character, mainly due to plastic activity of both phases. On the other hand, the cyclic response of aged material within this intermediate {var_epsilon}{sub pl} range is rather correlated to austenitic-like cyclic deformation mechanisms because of the intrinsic brittleness of the ferritic matrix. A third regime, at relatively large {var_epsilon}{sub pl}, suggests a synergetic phenomenon of dislocation activity, deformation twinning and demodulation of spinodal microstructure in ferrite that enables this phase to sustain plastic deformation. Thus, in this {var_epsilon}{sub pl} interval, the observed mechanical and substructural behavior within ferrite may be considered as relatively associated with ferritic-like cyclic deformation mechanisms. Finally, based on the results presented, the prevalence of austenitic-like or ferritic-like cyclic deformation mechanisms, for a given plastic strain range, is discussed in terms of the different role played by the ferritic matrix in each material investigated, depending upon its embrittlement degree.

• OSTI ID: 415394
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 10 Vol. 44; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGING
AUSTENITE
DEFORMATION
DISLOCATIONS
EMBRITTLEMENT
FATIGUE
FERRITE
HARDENING
MICROSTRUCTURE
PLASTICITY
STAINLESS STEELS
STRAINS
STRESSES
TWINNING