Microstructural stability of stressed lamellar and fiber composites
- Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering
- Lehigh Univ., Bethlehem, PA (United States). Dept. of Materials Science and Engineering
Microstructural stability can be modified by the presence of internal or applied stresses. The authors employ a linear stability analysis to examine the effect of stresses on the interface diffusion controlled morphological stability of lamellar (plate-like) and fibrous (rod-like phase) eutectic microstructures. These stresses can be either due to misfit strains and or externally applied loads. For misfitting plates, the nominally flat plate-matrix interface is unstable with respect to the growth of perturbations with wavelengths greater than a critical wavelength, provided that the plates are elastically stiffer than the surrounding matrix. In contrast, for stresses generated by externally applied loads, the flat plate-matrix interface is always unstable as long as the plate modulus and the matrix modulus are different. In addition, the present analysis shows that misfit strains can either counteract or enhance the destabilizing influence of applied loads, depending on the elastic properties of the plate and the matrix and the volume fraction of the two phases. For misfitting rods, the nominally cylindrical rod-matrix interface in an isotropic matrix is unstable with or without elastic effects. However, the elastic effects can decrease (increase) the maximally unstable wavelength over that predicted by curvature effects along provided that the rods are elastically stiffer (softer) than the surrounding matrix. Stresses generated by externally applied loads, on the other hand, always lead to a decrease in the instability wavelength compared with the Rayleigh instability wavelength. Stability diagrams are presented which identify the material properties and operating conditions required to maintain a stable interface in these eutectic microstructures.
- Sponsoring Organization:
- Department of the Air Force, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
- OSTI ID:
- 524531
- Journal Information:
- Acta Materialia, Vol. 45, Issue 7; Other Information: PBD: Jul 1997
- Country of Publication:
- United States
- Language:
- English
Similar Records
Multilayer film stability
Surface and defect morphologies in anisotropic elastic and piezoelectric solids