Understanding the Effect of Uniaxial Tensile Strain on the Early Stages of Sensitization in AISI 304 Austenitic Stainless Steel

TL;DR

This study investigates how uniaxial tensile strain influences early-stage sensitization in AISI 304 stainless steel, revealing complex interactions between deformation, temperature, and microstructural transformations affecting corrosion resistance.

Contribution

It provides new insights into the competing mechanisms controlling sensitization in deformed stainless steel during early stages, emphasizing the role of deformation-induced martensites.

Findings

DOS varies non-monotonically with strain and temperature.

Deformation-induced martensites influence sensitization behavior.

Transformation to tempered martensites affects desensitization processes.

Abstract

In the present study, an attempt has been made to understand the effect of different competing mechanisms controlling the overall degree of sensitization (DOS) of deformed austenitic stainless steel at the early stage of sensitization. The Double Loop Electrochemical Potentiokinetic Reactivation (DL-EPR) studies were performed to characterize the Degree of Sensitization (DOS) as functions of pre-defined strain and sensitization temperature. X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used to explain the phenomena qualitatively. A non monotonous behaviour in the variation of DOS has been observed with deformation and sensitization temperature. The presence of Deformation Induced Martensites (DIM) and their transformation into tempered martensites (alpha + Fe3C) at higher temperatures was found to play major roles in controlling the overall sensitization and desensitization processes.