Phase field approach to multiple twinning and variant-variant transformations in martensite
Arunabha Mohan Roy (Iowa State University), Valery Levitas (Iowa State University)
Mechanics of Phase Transforming and Multifunctional Materials
Tue 2:40 - 4:00
CIT 219
In the paper, an advanced phase field approach to transformation between martensitic variants and multiple twinning in martensitic variants is developed which resolves numerous existing problems. Large strain and rotation formulation is developed, which is not based on simple shears along all numerous possible twinning systems. New set of the order parameters is chosen that allowed us to describe transformation between martensitic variants Tj and Ti and all twinnings between them with a single order parameter. This gave us an opportunity to develop a strict and well-controlled description of Tj-Ti transformations and multiple twinnings, including expressions for interface tension, completely similar to that for phase transformation from austenite to single martensitic variants. The finite element algorithm and procedure is developed and implemented in the COMSOL and applied to the solution of a number of examples of twinning and combined austenite-martensite and martensite-martensite phase transformations and nanostructure evolution for various complex loadings. Examples include nano-indentation and double indentation, as well as thermally induce martensitic phase transformation. Twin tips bending and splitting, as well as twins crossing are reproduced. A similar approach can be developed for electric and magnetic phase transformations.