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Effect of Bake‐Hardening on the Structure‐Property Relationship of Multiphase Steels for the Automotive Industry
Author(s) -
Timokhina I.B.,
Hodgson P.D.,
Ringer S.P.,
Zheng R.K.,
Pereloma E.V.
Publication year - 2009
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.2374/sri08sp050
Subject(s) - trip steel , materials science , austenite , martensite , bainite , metallurgy , thermomechanical processing , microstructure , plasticity , dual phase steel , volume fraction , transmission electron microscopy , annealing (glass) , atom probe , strain hardening exponent , composite material , nanotechnology
The effect of a bake‐hardening (BH) treatment on the microstructure and mechanical properties has been studied in C‐Mn‐Si TRansformation Induced Plasticity (TRIP) and Dual Phase (DP) steels after: (i) thermomechanical processing (TMP) and (ii) intercritical annealing (IA). The steels were characterized using X‐ray diffraction, transmission electron microscopy (TEM) and three‐dimensional atom probe tomography (APT). All steels showed high BH response. However, the DP and TRIP steels after IA/BH showed the appearance of upper and lower yield points, while the stress‐strain behavior of the TRIP steel after TMP/BH was still continuous. This was due to the higher volume fraction of bainite and more stable retained austenite in the TMP/BH steel, the formation of plastic deformation zones with high dislocation density around the “as‐quenched” martensite and “TRIP” martensite in the IA/BH DP steel and IA/BH TRIP steel, respectively.