Alloy sensitivity and nature of deformation-induced phase transformation during sample preparation in Fe-Mn alloy

The present work investigates sample preparation-induced transformation in an Fe-Mn-based austenitic alloy. Mechanical polishing and electropolishing were carried out on the solution annealed alloy. Results show a near-complete austenitic structure γ (FCC) after electropolishing, whereas in the mechanically polished sample, along with γ-austenitic (FCC), ε-martensite (HCP), and α-martensite (BCC) were observed. These observations indicate that mechanical polishing of the samples led to deformation-induced martensitic transformation, resulting in sequential transformation to ε-martensite (HCP) and α-martensite (BCC). Stacking fault energy (SFE) and micro-strain calculated based on the XRD results were correlated with the critical shear stress requirements for the deformation-induced transformation. Based on this, insights are provided into the alloy susceptibility for such a transformation and the nature of the transformation.