|About this Abstract
||2020 TMS Annual Meeting & Exhibition
||Advanced High Strength Steels IV
||Measurement and Prediction of the Transformation Strain in High Strength Steels
||Francesco Maresca, Efthymios Polatidis, Miroslav Smid, Helena Van Swygenhoven, William Curtin
|On-Site Speaker (Planned)
Despite the critical importance, the transformation strain, which controls ductility and toughness in multiphase martensitic steels with metastable austenite, has never been measured in any alloy and has never been connected to underlying material properties. Here, we measure the transformation strain in a Fe-Ni-Mn alloy by combining state-of-the-art high-resolution digital image correlation, electron backscattered diffraction, scanning electron microscopy, and neutron diffraction. The experiments can be interpreted using a new parameter-free theory for the martensitic transformation. The predicted transformation strain agrees with the measurements, simultaneously demonstrating the method and validating the theory. Theory predicts that increasing the face-centered-cubic to body-centered-cubic lattice parameter ratio increases the transformation strain magnitude substantially. This new correlation is demonstrated using data on existing steels. These results establish a new broad design principle for tough alloys: control of the lattice parameter ratio by alloying. This provides a new path for development of even tougher advanced high-strength steels.
||Planned: Supplemental Proceedings volume