|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Advanced High-strength Steels
||About the Origins and the Effects of Internal Stresses in Retained Austenite of Q&P Steels
||Sébastien Y.P. Allain, Steve Gaudez, Guillaume Geandier, Jean-Christophe Hell, Samy Aoued, Mohamed Gouné, Michel Soler, Frédéric Danoix, Angéline Poulon
|On-Site Speaker (Planned)
||Sébastien Y.P. Allain
We have investigated and explained the origin of internal stresses in the retained austenite of a Q&P TRIP steel inherited from the thermal treatment.
Austenite undergoes first compressive hydrostatic stresses after the primary martensitic transformation. During reheating and final cooling, additional stresses are induced due to thermal eigenstrains due to the difference of coefficients of thermal expansion (CTE) between martensite and austenite. Micromechanical approaches are developed to model both contributions and adjusted on High Energy X-Ray Diffraction (HEXRD) in situ experiments. These measurements of internal stresses are highly sensitive to the choice of the coefficient of thermal expansion of the phases and possible plastic relaxation processes during partitioning. The final hydrostatic internal stresses in austenite of Q&P steels are key factors controlling the stability of this phase vs. a strain induced transformation at room temperature, which has been investigated by tensile experiments followed also by in situ HEXRD.
||Planned: Supplemental Proceedings volume