A Unified Approach to Motion of Grain Boundaries, Relative Tangetial Translation along Grain Boundaries, and Grain Rotation

Published

October 16, 2008

Author(s)

John W. Cahn, J E. Taylor

Abstract

Four phenomena associated with grain boundary mechanics and motion are unified into a single theoretical formulation: normal motion of a grain boundary resulting from a shear stress applied tangetial to it [LEWP][Shv]; rigid sliding of one grain with respect to the other along a greased boundary; grain rotation to decrease misorientation driven by the reduction in the surface free energy per unit area, as in the model of [JAW]; and grain rotation which increases misorientation as seen in the molecular dynamics simulations of [SC].We postulate that almost any motion of an interface between two crystals, e.g., growth one grain into the other, can produce a tangetial motion of the two crystals relative to each other which, apart from possible additional stress-induced rigid sliding along the grain boundary, is proportional to the normal motion of the interface. Such translation for embedded cylindrical crystals produces a rotation. A phenomenological formulation in special cases and a closely related variational model incorporating all cases are proposed to determine the growth and translation or rotation. A more thorough exploration of this concept, including application to non-circular crystals, is being published elsewhere [TC2].

Citation

Acta Materialia

Pub Type

Journals

Keywords

grain boundary motion, grain rotation, shear, sliding

Citation

Cahn, J. and Taylor, J. (2008), A Unified Approach to Motion of Grain Boundaries, Relative Tangetial Translation along Grain Boundaries, and Grain Rotation, Acta Materialia (Accessed November 8, 2024)