An Alternative Model for Investigating the Kinetics of Deformation-Induced Martensitic Transformation

Many austenitic stainless steels have a metastable austenite phase that transforms into α'-martensite during deformation at room and cryogenic temperatures. Given the significance of the deformation-induced martensitic transformation for strengthening, plasticity, and grain refinement, examining the kinetics of this transformation is an important issue. Accordingly, in the present work, an alternative kinetics model was introduced and verified by considering strain, deformation temperature, chemical composition, and strain rate as the main variables. This model was formulated as fα' / fsat = ۱/{۱+۱/(λε)m}, where fα' and fsat represent the volume fraction of α΄-martensite and its saturation value, respectively; ε is the equivalent strain, m was obtained as approximately ۳ for the effect of deformation temperature and strain rate on α'-martensite formation in AISI ۳۰۴ and AISI ۳۰۱LN stainless steels, and λ was found to be a reliable metastability parameter. In the proposed model, λ and m can be determined without the need for non-linear regression, which is a clear advantage compared to other models. The proposed model was benchmarked against the well-known Olson-Cohen model, highlighting its advantages and confirming that it can serve as a viable option for future research works on austenitic stainless steels, advanced high-strength steels, and high-entropy alloys.

کلیدواژه ها:

Metastable stainless steels ، Plastic deformation ، α' -martensite formation ، Austenite stability ، Phase transformation kinetics