Cyclic deformation behavior of a transformation-induced plasticity-aided dual-phase steel

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 28; no. 12; pp. 2637 - 2644
• Main Authors: SUGIMOTO, K.-I, KOBAYASHI, M, YASUKI, S.-I
• Format: Journal Article
• Language: English
• Published: New York, NY Springer 01.12.1997; Springer Nature B.V
• Subjects: Applied sciences; Bainite; Cross-disciplinary physics: materials science; rheology; Dual phase steels; Elasticity and anelasticity; Elasticity and anelasticity, stress-strain relations; Exact sciences and technology; Ferrite; Martensite; Materials science; Metals. Metallurgy; Physics; Plastic deformation; Residual stress; Retained austenite; Strain hardening; Temperature; Treatment of materials and its effects on microstructure and properties; Phase transformations; Electron diffraction; Cyclic loads; Mechanical properties; Bainite; Plastic deformation; Experimental study; Softening; Stress-strain relations; Hardening; Retained austenite; Ferrite; Internal stresses; Austenite; Plasticity; Dual-phase steels; SEM; Steels; TEM; Mechanical hysteresis; Bainitic transformation
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-997-0020-y

Cyclic hardening-softening behavior of a TRIP-aided dual-phase (TDP) steel composed of a ferrite matrix and retained austenite plus bainite second phase was examined at temperatures ranging from 20 °C to 200 °C. An increment of the cyclic hardening was related to (1) a long-range internal stress due to the second phase and (2) the strain-induced transformation (SIT) behavior of the retained austenite, as follows. Large cyclic hardening, similar to a conventional ferrite-martensite dual-phase steel, appeared in the TDP steel deformed at 20 °C, where the SIT of the retained austenite occurred at an early stage. This was mainly caused by a large increase in strain-induced martensite content or strain-induced martensite hardening, with a small contribution of the internal stress. In this case, shear and expansion strains on the SIT considerably decreased the internal stress in the matrix. With increasing deformation temperature or retained austenite stability, the amount of cyclic hardening decreased with a significant decrease in plastic strain amplitude. This interesting cyclic behavior was principally ascribed to the internal stress, which was enhanced by stable and strain-hardened retained austenite particles.