Microstructure Evolution during Strain-Induced Transformation of Austenite in an Austempered Ductile Iron (ADI)

Abstract:

Microstructural evolution during the strain-induced phase transformation of austenite in an Austempered ductile iron (ADI) under various thermomechanical processing conditions is studied in the present study. An alloyed ductile iron is taken as the base material, and thermomechanical treatment is carried out on a Gleeble 3800 thermomechanical simulator coupled with dilatometry. The effect of deformation on the austempering process has been studied by microstructure characterization using optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The variations in retained austenite volume fraction and its carbon content with respect to different austempering times are analyzed to study the effect of strain-induced transformation of austenite. It has been observed that the thermomechanical treatment significantly influences the phase transformation kinetics during the austempering process. The thermomechanical treatment produced a martensite free ausferritic microstructure for all austempering times with a high volume fraction of carbon enriched retained austenite as compared to the conventional heat treatment.

• Periodical: Materials Science Forum (Volume 1016)
• Pages: 1199-1204
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1016.1199
• Online since: January 2021
• Authors: R. Raghavendran*, Anil Meena, Murugaiyan Amirthalingam
• Keywords: Austempered Ductile Iron, Gleeble 3800, Retained Austenite, Thermomechanical Treatment

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