Y. Wang, The Ohio State University, Columbus, OH; R. Shi, N. Zhou, Ohio State University, Columbus, OH
The effect of local stress in a polycrystalline aggregate on variant selection during a ® b transformation in Ti-64 was investigated using quantitative 3D phase field models. The stress field in a single b phase polycrystalline sample under an external load was first calculated using a phase field microelasticity model developed for elastically anisotropic and inhomogeneous media. The local stress field was then imported into a phase field model of a ® b transformation where the effects of stress and grain boundary on variant selection during nucleation and growth of a phase were captured. The spatial distribution of different variants of the a phase was found to correlate strongly with the stress distribution in the polycrystalline sample. Under certain circumstances, certain variants may percolate through the entire sample. The work is supported by ONR under D 3-D program.
Summary: The effect of local stress in a polycrystalline aggregate on variant selection during ƒÑ „_ ƒÒ transformation in Ti-64 was investigated using quantitative 3D phase field models. The stress field in a single ƒÒ phase polycrystalline sample under an external load was first calculated using a phase field microelasticity model developed for elastically anisotropic and inhomogeneous media. The local stress field was then imported into a phase field model of ƒÑ „_ ƒÒ transformation where the effects of stress and grain boundary on variant selection during nucleation and growth of ƒÑ phase were captured. The spatial distribution of different variants of the ƒÑ phase was found to correlate strongly with the stress distribution in the polycrystalline sample. Under certain circumstances, certain variants may percolate through the entire sample. The work is supported by ONR under D 3-D program.
