Future Trends on Displacive Stress and Strain Induced Transformations in Steels

Abstract

Displacive stress and strain induced transformations are those transformations that occur when the formation of martensite or bainitic ferrite is promoted by the application of stress or strain. These transformations have been shown to be one of the mechanisms by which the mechanical properties of a microstructure can be improved, as they lead to a better ductility and strength by the transformation induced plasticity effect. This review aims to summarize the fundamental knowledge about them, both in fully austenitic or in multiphase structures, pointing out the issues that—according to the authors’ opinion—need further research. Knowing the mechanisms that govern the stress and strain induced transformation could enable to optimize the thermomechanical treatments and improve the final microstructure properties.

Modelling the stability and transformation kinetics of retained austenite in steels

“…There is no consensus in the role of stress and strain in deformation-induced transformations [51,85,86,88,100]. Further work is needed to elucidate the influence of stress and strain on martensite transformation [56]. The transformation rate parameter in models should have some physical meaning.…”

“…For a deeper review on the theory of deformation-induced martensitic transformations, the reader is directed to the work of Eres-Castellanos et al [56]. The authors also performed thermodynamics-based calculations of the critical temperatures for deformation-induced martensitic and bainitic transformations in an ausformed steel [57].…”

Microstructural Evolution in a 0.09% Niobium Low Carbon Steel during Controlled Hot Deformation

“…The first observations of the dynamic transformation were reported in the patent registered in the 1980s [1], who performed large deformations in common C-Mn steels at approximately the Ar 3 temperature and then rapidly quenched, the final microstructure consisted of 70% or more of equiaxed ferrite grains with a size of 4 µm or less. In later works [2][3][4][5][6][7][8], the dynamic transformation was also observed at temperatures above the Ae 3 in plain carbon steels, the combination of large strains and multiple passes conducted to ultrafine grains of ferrite of around 2 µm. Extensive research has been carried out after the pioneering work of Yada and co-workers and numerous papers have been published mainly in the last two decades.…”

A critical review on deformation-induced transformation kinetics of austenitic stainless steels

“…6,14,15,[30][31][32][33][34] and emphasize on the importance of austenite stability in tailoring the mechanical properties of the steels. Castellanos et al 35 reviewed various thermomechanical routes to carry out the stress and strain-induced transformation in single phase fully austenitic steels and in multiphase microstructures. Authors discussed the importance of stacking fault energy (SFE) and different sequences of microstructural changes taking place during deformation-induced transformation.…”