Austenite stability and deformation behavior in a cold-rolled transformation-induced plasticity steel with medium manganese content. (1st February 2015)

• Record Type: Journal Article
• Authors: Cai, Z.H.; Ding, H.; Misra, R.D.K.; Ying, Z.Y.
• Is Part Of: Acta materialia. Volume 84(2015)
• Page Start: 229
• Page End: 236
• Publication Date: 2015-02-01
• Subjects: Austenite stability -- Discontinuous TRIP effect -- Mechanical properties -- Work hardening -- Manganese distribution; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2014.10.052
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: We elucidate here the impact of grain size and manganese concentration on the austenite stability and the deformation behavior of a cold-rolled transformation-induced plasticity (TRIP) steel with a nominal chemical composition of Fe–11Mn–4Al–0.2C (wt.%). Intercritical hardening at 770 °C led to a ferrite–austenite mixed microstructure, which was characterized by an excellent combination of ultimate tensile strength of 1007 MPa and total elongation of 65% and a three-stage work-hardening behavior. The grain size was a critical factor in governing the stability of austenite and the optimal grain size for maximum stability was observed to be ∼0.6 μm. The superior mechanical properties are attributed to the discontinuous TRIP effect and the cooperative deformation of ferrite, where the discontinuous effect is a consequence of the non-uniform distribution of manganese, which is responsible for introducing varying degrees of stability in the austenite phase.