EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Diverse pathways of {332}<113>β mechanical twinning and stress induced martensitic transformation (BCC-Orthorhombic) were studied in a metastable beta Ti-12Mo alloy, which presents Transformation Induced Plasticity (TRIP) / Twinning Induced Plasticity effect. This work aims to clarify the pathways involved in primary and secondary transformations under external tensile stress, such as the hierarchal transformations in {332}<113>β twin and the twinning-detwinning processes of stress-induced α″ martensite (SIMα″). The grain resolved transformations were traced by in-situ EBSD (Electron backscatter diffraction) mapping and in-situ TEM (Transmission electron microscope) observation under tensile loading and unloading conditions. Observations of unprecedented pathways between {332}<113>β twinning and SIMα″ are achieved by transformation partition mapping via in-situ EBSD statistic coupled with Schmid factor analysis. At finer length scales under in-situ TEM observations, the nucleation behaviors, growth kinetics and the reversible internal transformations are further investigated of both {332}<113>β twinning and SIMα″.