TY - GEN
T1 - Deformation microstructures in a two-phase stainless steel during large strain deformation
AU - Tsuzaki, Kaneaki
AU - Belyakov, Andrey
AU - Kimura, Yuuji
PY - 2006/12/1
Y1 - 2006/12/1
N2 - Deformation microstractures were studied in a two-phase (about 60% ferrite and 40% austenite) Fe - 27%Cr - 9%Ni stainless steel. Severe plastic working was carried out by rolling from 21.3×21.3 mm2 to 7.8×7.8 mm2 square bar followed by swaging from Ø7.0 to 0.6 mm rod at an ambient temperature, providing a total strain of 6.9. After a rapid increase in the hardness at an early deformation, the rate of the strain hardening gradually decreased to almost zero at large strains above 4. In other words, the hardness approached a saturation level, leading to an apparent steady-state deformation behaviour during cold working. The severe deformation resulted in the evolution of highly elongated (sub)grains aligned along the rolling/swaging axis with the final transverse (sub)grain size of about 0.1 μm and the fraction of high-angle (sub)boundaries above 60%. However, the kinetics of microstructure evolution in the two phases was different. In the ferrite phase, the transverse size of deformation (sub)grains gradually decreased during the processing and approached 0.1 μm at strains of about 6.0, while the transverse size of the austenite (sub)grains rapidly reduced to its final value of 0.1 μm after a relatively low strain about 1.0.
AB - Deformation microstractures were studied in a two-phase (about 60% ferrite and 40% austenite) Fe - 27%Cr - 9%Ni stainless steel. Severe plastic working was carried out by rolling from 21.3×21.3 mm2 to 7.8×7.8 mm2 square bar followed by swaging from Ø7.0 to 0.6 mm rod at an ambient temperature, providing a total strain of 6.9. After a rapid increase in the hardness at an early deformation, the rate of the strain hardening gradually decreased to almost zero at large strains above 4. In other words, the hardness approached a saturation level, leading to an apparent steady-state deformation behaviour during cold working. The severe deformation resulted in the evolution of highly elongated (sub)grains aligned along the rolling/swaging axis with the final transverse (sub)grain size of about 0.1 μm and the fraction of high-angle (sub)boundaries above 60%. However, the kinetics of microstructure evolution in the two phases was different. In the ferrite phase, the transverse size of deformation (sub)grains gradually decreased during the processing and approached 0.1 μm at strains of about 6.0, while the transverse size of the austenite (sub)grains rapidly reduced to its final value of 0.1 μm after a relatively low strain about 1.0.
UR - http://www.scopus.com/inward/record.url?scp=35248814256&partnerID=8YFLogxK
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M3 - Conference contribution
AN - SCOPUS:35248814256
SN - 0878499857
SN - 9780878499854
T3 - Materials Science Forum
SP - 305
EP - 310
BT - Nanomaterials by Severe Plastic Deformation, NanoSPD3 - Proceedings of the 3rd International Conference on Nanomaterials by Severe Plastics Deformation
T2 - 3rd International Conference on Nanomaterials by Severe Plastics Deformation, NanoSPD3
Y2 - 22 September 2005 through 26 September 2005
ER -