The nature of the TRIP-effect in metastable austenitic steels

Abstract The TRIP-effect in metastable austenitic steels is caused by a moderate local martensitic transformation, influencing both the strain hardening and the damage behaviour. The main conditions of a marked TRIP-effect are a low flow stress in the undeformed state, a high strain hardening exponent, a continuous martensitic transformation up to about 20% and a high resistance to damage (e.g. crack formation and propagation). The martensite transformation starts in glide or shear bands and their intersections even at temperatures clearly above the conventional Md-temperatures, reducing the local stress concentrations and so preventing the onset of damage. Furthermore, high martensite content can be detected along the fracture path impeding the crack propagation by the transformation. To demonstrate the influence of damage on the TRIP-effect the deviations from the so-called Considere-criterion for maximum uniform elongation can be used.

[1]  D. P. Koistinen,et al.  A general equation prescribing the extent of the austenite-martensite transformation in pure iron-carbon alloys and plain carbon steels , 1959 .

[2]  G. W. Greenwood,et al.  The deformation of metals under small stresses during phase transformations , 1965, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[3]  Gregory B Olson,et al.  Kinetics of strain-induced martensitic nucleation , 1975 .

[4]  I. Tamura,et al.  Deformation-induced martensitic transformation and transformation-induced plasticity in steels , 1982 .

[5]  R. G. Stringfellow,et al.  A constitutive model for transformation plasticity accompanying strain-induced martensitic transformations in metastable austenitic steels , 1992 .

[6]  Franz Dieter Fischer,et al.  Transformation-Induced Plasticity (TRIP) , 1996 .

[7]  E. Werner,et al.  A new view on transformation induced plasticity (TRIP) , 2000 .

[8]  M. Cherkaoui,et al.  Mechanics of Materials Undergoing Martensitic Phase Change: A Micro-Macro Approach for Transformation Induced Plasticity , 2000 .

[9]  O. Bouaziz,et al.  Modelling of TWIP effect on work-hardening , 2001 .

[10]  F. Delannay,et al.  On the role of martensitic transformation on damage and cracking resistance in trip-assisted multiphase steels , 2001 .

[11]  U. Prahl,et al.  Micromechanical Damage Simulations of TRIP Steels , 2003 .

[12]  A. ADoefaa,et al.  ? ? ? ? f ? ? ? ? ? , 2003 .

[13]  U. Martin,et al.  On the Deformation Behaviour and Martensitic Transformations of Metastable Austenitic Steels , 2004 .

[14]  Arno Behrens,et al.  Theoretical and Experimental Damage Prediction in Cold and Semi-Hot Bulk Forming of Ductile Steels , 2005 .