J. Phys. IV France 112 (2003) 457
Martensitic transformation induced by quenching or by plastic deformationI. Félix-Henry1, C. Dagbert1, L. Hyspecka2 and J. Galland1
1 École Centrale de Paris, Laboratory Corrosion, Embrittlement, Hydrogen, Grande Voie des Vignes, 92295 Châtenay-Malabry cedex, France
2 Technical University of Ostrava, 17 Listopadu 15, 70833 Ostrava-Poruba, Czech Republic
Nowadays the possibility to use the TRIP effect (Transformation Induced Plasticity) is stated not only for the high alloy steels but also for the low alloy steels. This effect is connected with the martensitic transformation, but not necessarily the strain induced martensitic transformation induced by deformation provokes the TRIP effect: decisive factors are the chemical composition, the stability of the austenite, its grain size, the particles geometry and their distribution, and also the temperature, amplitude and rate of deformation during the mechanical loading. The change of energy is compared between the creation of the quench and strain induced martensite with and without the TRIP effect. The molar enthalpy released during the creation of quench induced martensite in the continually cooled austenite of the alloy Fe-23.87wt %Ni-0.39wt %C, was calculated from DSC (differential scanning calorimeter) measurements. For this same material, the consumed work during tensile tests was determined at different temperatures. The temperatures interval was between Ms and Md. At each température, a volume traction of strain induced martensite was created and thé TRIP effect could occur, that is both extraordinary great elongation at high ultimate tensile strength and nearly no local deformation (no creation of a neck). This paper conclues with a discussion on the preferences and lacks in the use of TRIP effect in low alloy steels.
© EDP Sciences 2003