INVESTIGATION ON DEFORMATION MODE DEPENDENCE OF STRAIN-INDUCED MARTENSITIC-TRANSFORMATION IN TRIP STEELS AND MODELING OF TRANSFORMATION KINETICS

TRIP steel possesses favorable mechanical properties such as high stre ngth, ductility and toughness and is frequently employed as structural material. To obtain the expected mechanical properties of TRIP steels through cold-working conditions, prediction and control of the materi al characteristics during the deformation processes are indispensable. Here, to evaluate such macroscopic characteristics as the stress-stra in relationship and the average volume fraction of the overall specime n and such microscopic characteristics as shape, orientation and perio dicity of the martensitic particles, uniaxial tension and compression tests, including SEM observation, for 304 austenitic stainless steels have been carried out under various environmental temperature conditio ns. On the basis of the experimental results, the deformation mode dep endence of martensitic transformation and deformation behavior of TRIP steels are discussed. Finally, a deformation-mode-dependent transform ation kinetics model is presented. (C) 1997 Published by Elsevier Scie nce Ltd.