|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||High Performance Steels
||Deformable Plastic Strain-induced Epsilon-martensite in FeMnCo Alloys: A Pathway Towards Overcoming the Limits of Metastability
||Shaolou Wei, Cem Tasan
|On-Site Speaker (Planned)
In contrast to pseudo-elastic martensitic phases, typical BCT-martensite formed through plastic straining often exhibits brittle-like features, largely ascribed to the extensive defect density and the pronounced plastic accommodation in the vicinal parent phase. A somewhat intermediate situation occurs when epsilon-martensite is nucleated during plastic deformation: the similar atomic stacking sequence between HCP and FCC lattices enables more moderate interfacial mismatch, alleviating plastic accommodation. In light of this, we will show that through appropriate compositional design, highly deformable strain-induced epsilon-martensite can be achieved in ternary FeMnCo alloys. We will detail in this presentation: (1) the exploration of a sequential FCC-HCP-FCC martensitic transformation chain by plastic straining; (2) the understanding of an atomic shuffle-involved “twinning” in strain-induced epsilon-martensite; and (3) the atomistic procedures that accomplish “twinned” epsilon-martensite to final FCC transformation. Finally, a discussion towards the feasibility of multi-stage TRIP/TWIP metastability engineering will also be included.
||Phase Transformations, Characterization,