| Issue |
J. Phys. Colloques
Volume 49, Number C5, Octobre 1988
Interface Science and Engineering '87An International Conference on the Structure and Properties of Internal Interfaces |
|
|---|---|---|
| Page(s) | C5-769 - C5-779 | |
| DOI | https://doi.org/10.1051/jphyscol:1988596 | |
An International Conference on the Structure and Properties of Internal Interfaces
J. Phys. Colloques 49 (1988) C5-769-C5-779
DOI: 10.1051/jphyscol:1988596
MEASUREMENTS OF THE ELASTIC CONSTANTS, THE SPECIFIC HEAT AND THE ENTROPY OF GRAIN BOUNDARIES BY MEANS OF ULTRA-FINE GRAINED MATERIALS
D. KORN1, A. MORSCH2, R. BIRRINGER1, W. ARNOLD2 et H. GLEITER11 Universität des Saarlandes, FB 12.1, Bau 2, D-6600 Saarbrücken, F.R.G.
2 Fraunhofer Institut für Zerstörungsfreie Prüfverfahren, Universität des Saarlandes, Bau 37, D-6600 Saarbrücken, F.R.G.
Abstract
Measurements of the elastic constants, the specific heat and the entropy of grain boundaries have been performed by utilizing ultra-fine grained materials (Pd, 6nm grain size ; Mg, 12 nm grain size ; CaF2, 7 nm grain size) about 30 to 50 vol% of which consist of grain boundaries. The results obtained suggest that (1) The interatomic potentials in grain boundaries in metals differ from the lattice potentials. Hence, the application of lattice potentials for computer simulation of boundary structures in metals may be of limited physical relevance. (2) Boundary entropy effects are significant for the interfacial structure above half the absolute melting temperature. (3) Metastable boundary structures with enhanced boundary entropies exist. The entropy enhancement may be several times the entropy of an equilibrated interface in the same material.