Stress-assisted isothermal martensitic transformation: Application to TRIP steels

Abstract

Low-temperature plastic flow in TRIP steels has been found to be controlled by stress-assisted isothermal martensitic transformation. For these conditions, the thermodynamics and kinetic theory of martensitic transformations leads directly to constitutive relations predicting the dependence of flow stress on temperature, strain, strain-rate, and stress-state, consistent with the observed behavior of TRIP steels. Guidelines are obtained for the control of temperature sensitivity, tr-e curve shape, and stress-state effects to achieve novel mechanical properties.

More Complete Theory for the Calculation of the Martensite–Start Temperature in Steels

“…33) The influence of stress per se is expressed via a mechanical driving force 12) which supplements the chemical component, and has been estimated on the basis of the shape deformation of martensite as: 34) = 0.86σ for uniaxial tension = 0.58σ for uniaxial compression ..... (1) where the driving force is in J mol -1 and the stress in MPa. Such calculations can in fact be done for arbitrary stress tensors, 35) but most experiments are done in uniaxial mode.…”

Metastable Ferrous Austenite - Consequences on Fracture and Tribology

“…However, some undesirable consequences, most notably inhompgeneous yielding and extreme temperature sensitivity have hampered the practical development and application of the high-strength TRIP steels (22,23). In the optimum temperature range only a small amount of adiabatic heating is required to drastically alter the shape of stress-strain curve with an attendant serious loss of uniform ductility.…”

Texture analysis of deformation induced martensite in an AISI 301L stainless steel: microtexture and macrotexture aspects

“…The amount of martensite depends on processing parameters such as stress state of the material, temperature and rate of deformation. The steel composition and stacking fault energy can also exert great influence [1][2][3][4][5][6][7] . When shear stress is applied at temperatures near M s , displacive transformation (martensitic transformation) mode is activated.…”