Phase field modeling of Widmanstatten plate formation in Zr-2.5Nb material

Growth of Widmanstatten side-plates from pre-nucleated alpha in a matrix of beta is a diffusion controlled process. The phase-field approach is formulated for Widmanstatten side plate formation through beta-Zr (B.C.C) -> alpha-Zr (HCP) transformation in binary substitutional Zr-2.5Nb alloy. Using Gibbs energy functional and diffusional mobility, microstructural evolution of parallel side-plates from pre-nucleated alpha phase has been simulated. The highly anisotropic nature of Widmanstatten plate and the presence of thin interface at the parent-product interface make the task challenging for FEM analysis. Based on this model, an estimate on the range of temperature over which Widmanstatten parallel side-plates can form is estimated and the extent of anisotropy of surface free energy on the morphology of the plates is analyzed. (C) 2013 The Authors. Published by Elsevier B.V. Open access under CC BY-NC-ND license.