Experimental and numerical study of the mechanical behavior and kinetics of the martensitic transformation in 304L TRIP steel: applied to folding

Abstract : In this paper, experimental and phenomenological modeling of the mechanical behavior and austenite-martensitic transformation after deformation in 304L TRIP steel is investigated. Mechanical behavior and the evolution of the microstructure after folding test were studied 25 A degrees C. Scanning electron microscopy (SEM), Vickers hardness measurements, and X-ray diffraction test were conducted in order to characterize the deformation response and microstructure evolution of 304L TRIP steel. The analysis results indicate that both the microstructure and mechanical properties of the 304L TRIP steel varied gradually during the tests, the later showed too that the most favorable way for the formation of martensite is tension. Secondly, a phenomenological constitutive model, developed by Iwamoto et al., was selected and modified to include the microstructure evolution (austenite to martensite) after deformation. The validity and the limitation of the simulations are checked against the experimentally established stress-strain relation and the evolution of martensite phase. The simulation results show that the volume fraction of martensite is proportional to the strain and it is very important in the tended zone than the compressed zone. The results above present a foundation for the folding control technology.