Austenite Stability Effects on Tensile Behavior of Manganese-Enriched-Austenite Transformation-Induced Plasticity Steel

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 42; no. 12; pp. 3691 - 3702
• Main Authors: Gibbs, P. J., De Moor, E., Merwin, M. J., Clausen, B., Speer, J. G., Matlock, D. K.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.12.2011; Springer Nature B.V
• Subjects: Annealing; Austenite; Austenitic stainless steel; Characterization and Evaluation of Materials; Chemistry and Materials Science; Cold rolling; Enrichment; Manganese; Manganese steel; Materials Science; Metallic Materials; Nanotechnology; Plastics; Stability; Steels; Strain hardening; Structural Materials; Surfaces and Interfaces; Symposium: Austenite Formation and Decomposition IV; Tensile strength; Thin Films; Ferrite; Duplex Stainless Steel; Martensite; Shear Band; Austenite
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-011-0687-y

Manganese enrichment of austenite during prolonged intercritical annealing was used to produce a family of transformation-induced plasticity (TRIP) steels with varying retained austenite contents. Cold-rolled 0.1C-7.1Mn steel was annealed at incremental temperatures between 848 K and 948 K (575 °C and 675 °C) for 1 week to enrich austenite in manganese. The resulting microstructures are comprised of varying fractions of intercritical ferrite, martensite, and retained austenite. Tensile behavior is dependent on annealing temperature and ranged from a low strain-hardening “flat” curve to high strength and ductility conditions that display positive strain hardening over a range of strain levels. The mechanical stability of austenite was measured using in-situ neutron diffraction and was shown to depend significantly on annealing temperature. Variations in austenite stability between annealing conditions help explain the observed strain hardening behaviors.