Constitutive Modeling of Single Crystal TRIP Steel Based on Transformation - Crystal Plasticity Theory and Computational Simulation of Its Transformation and Deformation Behavior by Cellular Automata Approach
Takeshi IWAMOTO, Toshiyuki SAWA and Shinji KUBO
Abstract:Due to the strain-induced martensitic transformation (SIMT), the strength, ductility and toughness of TRIP steel are enhanced. TRIP steel possesses such favorable macroscopic mechanical properties as a result of the appropriate combination between this SIMT behavior and the deformation behaviors of the austenitic and martensitic phases at a scale of crystal grain. Recently, a texture evolution by martensitic transformation is being focused on and it is possible that the control of such favorable mechanical properties of TRIP steels will be realized by the control of the texture evolution by SIMT. Therefore, not only the appropriate constitutive model at the scale of a single crystal but also a suitable model for a formation of a microstructure are necessary to predict this transformation texture evolution. Here, the constitutive equation for a single crystal TRIP steel including transformation strain on each variant is formulated based on the continuum crystal plasticity theory. Then, the deformation behavior with patterning process of martensitic phase is simulated under plane strain condition by introducing formulated constitutive equation to FEM with cellular automata approach. Key Words:Computational mechanics, FEM, Constitutive equation, TRIP steel, Strain-induced martensitic transformation, Crystal plasticity, Cellular automata, Pattern formation