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Title: Influence of microstructure on the flow behavior of duplex stainless steels at high temperatures

Abstract

Three kinds of duplex stainless steel, with different ferrite-to-austenite ratios, were deformed in torsion over the temperature range 900 C to 1,200 C; the corresponding microstructural evolution was observed and correlated with the deformation conditions. The shapes of the high-temperature flow curves depend strongly on the volume fractions of the phases, the characteristics of the ferrite-austenite interface, and the active softening mechanism. At low volume fractions of austenite, the mechanical behavior is determined by the ferrite matrix and the flow curves are typical of materials that soften by continuous dynamic recrystallization. When the volume fraction of austenite is increased, coherent {gamma} particles distributed within the grains and at the grain boundaries hinder the deformation of the softer {alpha} matrix, increasing both the yield and the peak stress. These peaked flow curves are characterized by rapid work hardening followed by extensive flow softening; under these conditions, the hard austenite particles become aligned with the deformation direction after large strains. AT high volume fractions of austenite ({approximately}50%), the material tends to form a duplex structure, with the flow curves displaying extended work-hardening and work-softening regions; however, a drastic decrease is observed in ductility because of the dissimilar plastic behaviors of the twomore » phases.« less

Authors:
; ;
Publication Date:
Research Org.:
Univ. Federal de Sao Carlos (BR)
OSTI Identifier:
20075678
Alternate Identifier(s):
OSTI ID: 20075678
Resource Type:
Journal Article
Journal Name:
Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science
Additional Journal Information:
Journal Volume: 31; Journal Issue: 5; Other Information: PBD: May 2000; Journal ID: ISSN 1073-5623
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MICROSTRUCTURE; DEFORMATION; STAINLESS STEELS; TEMPERATURE RANGE 1000-4000 K; FERRITE; AUSTENITE; STRAIN HARDENING; CORRELATIONS

Citation Formats

Balancin, O., Hoffmann, W.A.M., and Jonas, J.J. Influence of microstructure on the flow behavior of duplex stainless steels at high temperatures. United States: N. p., 2000. Web. doi:10.1007/s11661-000-0254-4.
Balancin, O., Hoffmann, W.A.M., & Jonas, J.J. Influence of microstructure on the flow behavior of duplex stainless steels at high temperatures. United States. doi:10.1007/s11661-000-0254-4.
Balancin, O., Hoffmann, W.A.M., and Jonas, J.J. Mon . "Influence of microstructure on the flow behavior of duplex stainless steels at high temperatures". United States. doi:10.1007/s11661-000-0254-4.
@article{osti_20075678,
title = {Influence of microstructure on the flow behavior of duplex stainless steels at high temperatures},
author = {Balancin, O. and Hoffmann, W.A.M. and Jonas, J.J.},
abstractNote = {Three kinds of duplex stainless steel, with different ferrite-to-austenite ratios, were deformed in torsion over the temperature range 900 C to 1,200 C; the corresponding microstructural evolution was observed and correlated with the deformation conditions. The shapes of the high-temperature flow curves depend strongly on the volume fractions of the phases, the characteristics of the ferrite-austenite interface, and the active softening mechanism. At low volume fractions of austenite, the mechanical behavior is determined by the ferrite matrix and the flow curves are typical of materials that soften by continuous dynamic recrystallization. When the volume fraction of austenite is increased, coherent {gamma} particles distributed within the grains and at the grain boundaries hinder the deformation of the softer {alpha} matrix, increasing both the yield and the peak stress. These peaked flow curves are characterized by rapid work hardening followed by extensive flow softening; under these conditions, the hard austenite particles become aligned with the deformation direction after large strains. AT high volume fractions of austenite ({approximately}50%), the material tends to form a duplex structure, with the flow curves displaying extended work-hardening and work-softening regions; however, a drastic decrease is observed in ductility because of the dissimilar plastic behaviors of the two phases.},
doi = {10.1007/s11661-000-0254-4},
journal = {Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science},
issn = {1073-5623},
number = 5,
volume = 31,
place = {United States},
year = {2000},
month = {5}
}