Capillarity driven motion of solid film wedges
- Northwestern Univ., Evanston, IL (United States)
A solid film freshly deposited on a substrate may form a non-equilibrium contact angle with the substrate, and will evolve. This morphological evolution near the contact line is investigated by studying the motion of a solid wedge on a substrate. The contact angle of the wedge changes at time t = 0 from the wedge angle {alpha} to the equilibrium contact angle {beta}, and its effects spread into the wedge via capillarity-driven surface diffusion. The film profiles at different times are found to be self-similar, with the length scale increasing as t{sup 1 4}. The self-similar film profile is determined numerically by a shooting method for {alpha} and {beta} between 0 and 180. In general, the authors find that the film remains a wedge when {alpha} = {beta}. For {alpha} < {beta}, the film retracts, whereas for {alpha} > {beta}, the film extends. For {alpha} = 90{degree}, the results describe the growth of grain-boundary grooves for arbitrary dihedral angles. For {beta} = 90{degree}, the solution also applies to a free-standing wedge, and the thin-wedge profiles agree qualitatively with those observed in transmission electron microscope specimens.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-95ER25241
- OSTI ID:
- 514664
- Journal Information:
- Acta Materialia, Vol. 45, Issue 6; Other Information: PBD: Jun 1997
- Country of Publication:
- United States
- Language:
- English
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