Thermal grain boundary grooving with anisotropic surface free energies

2004 ◽  
Vol 52 (1) ◽  
pp. 107-116 ◽  
Author(s):  
W Zhang ◽  
P Sachenko ◽  
I Gladwell
Keyword(s):  
Grain Boundary ◽  
Free Energies ◽  
Anisotropic Surface

The Effect of Interfacial Free Energies on the Stability of Microlaminates

2000 ◽  
Vol 652 ◽  
Author(s):  
A. C. Lewis ◽  
A. B. Mann ◽  
D. van Heerden ◽  
D. Josell ◽  
T. P. Weihs
Keyword(s):  
Electron Microscopy ◽  
Grain Boundary ◽  
High Temperatures ◽  
Free Energies ◽  
Microstructural Stability ◽  
Creep Tests ◽  
Interfacial Energies ◽  
Transmission Electron ◽  
The Stability ◽  
Interfacial Free Energies

ABSTRACTLaminated composites with polycrystalline layers typically break down at high temperatures through grain boundary grooving and the pinch-off of individual layers. Such materials, when exposed to high temperatures, develop grooves where grain boundaries meet the interfaces between layers. The depths of the grooves are controlled by the ratios of grain boundary and interfacial free energies, γgb/γint. Depending on the dimensions of the grains, these grooves can extend through the entire layer, causing pinch-off at the grain boundary. This pinch-off destroys the layering and eventually leads to a gross coarsening of the microstructure. Because microstructural stability is critical to performance for most applications, the ability to understand and predict the stability of microlaminates is a necessary tool. An existing model of this capillarity-driven breakdown requires the interfacial free energies, γgb and γint, as input parameters. Both biaxial and uniaxial zero creep tests have been used in conjunction with transmission electron microscopy to measure these interfacial energies in Ag/Ni and Nb/Nb5Si3 microlaminates.

scholarly journals Optical Measurements of Water Lenses in Ice

1987 ◽  
Vol 33 (114) ◽  
pp. 159-161 ◽  
Author(s):  
M.E.R. Walford ◽  
D.W. Roberts ◽  
I. Hill
Keyword(s):  
Grain Boundary ◽  
Specific Surface ◽  
Dihedral Angle ◽  
Focal Length ◽  
Water System ◽  
Optical Measurements ◽  
Free Energies ◽  
Minor Revision ◽  
Experimental Values ◽  
Ice Water

AbstractThe dihedral angle of water at a grain boundary in ice is found, by measuring the optical focal length of lenticular water inclusions, to be 33.6 ± 0.7°. The new result leads to only minor revision of published experimental values of specific surface free energies in the ice–water system (Ketcham and Hobbs, 1969).

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