Influence of intercritical deformation on microstructure of TRIP steels containing Al

The influence of intercritical deformation on the microstructure development of a TRIP steel has been investigated by the use of deformation dilatometry, X-ray diffraction, and metallography. The austenite decomposition into ferrite and bainite during cooling from the intercritical annealing and the bainitic annealing have been investigated. A very distinct effect of plastic deformation on the microstructural development has been observed. Since the plastic deformation enhances the ferrite formation during cooling, the degree of deformation can be used to control the balance between allotriomorphic ferrite and bainitic ferrite in the eventual structure. In this paper a semi-quantitative phase map has been developed, showing the microstructural composition of the material as a function of the degree of plastic deformation. Using this map the influence of the intercritical deformation on the microstructure development can be followed. [PUBLICATION ABSTRACT]