Orientation dependence of Ge diffusion along symmetrical [111] tilt grain boundaries in Al
- Univ. Muenster (Germany). Inst. fuer Metallforschung
- RWTH Aachen (Germany). Inst. fuer Metallkunde und Metallphysik
Grain boundary diffusion of Ge was measured in a series of Al bicrystals with symmetrical near {Sigma} = 7, {Theta} = 38.2 (12{bar 3}) [111] tilt grain boundaries (GBs). The actual orientations of the bicrystals were precisely measured with a modified Kossel-technique. All three macroscopic parameters describing the orientation of the grains in the bicrystals were determined. The tilt angles {Theta} ranged from 34.15 to 41.41{degree}. GB diffusion measurements were performed parallel to the tilt axis in the type B kinetic regime in the temperature interval 518--680 K using the radiotracer {sup 71}Ge and the serial sectioning technique. A characteristic non-continuous dependence of the measured GB diffusion parameter s{delta}D{sub GB} on the tilt angle {Theta} was observed for all five investigated diffusion temperatures. The GB diffusion parameter reveals a distinct minimum at the orientation of the ideal {Sigma} = 7, {Theta} = 38.2{degree} (12{bar 3}) [111] boundary while the corresponding Arrhenius parameters (s{sub 0}{delta}D{sub GB}) and Q{sub GB} adopt a maximum. The orientation dependence of the GB diffusion is discussed in terms of the diffusion concept of CSL boundaries. Different from the previous GB diffusion investigation in near {Sigma} = 5, {Theta} = 36.9{degree} (310)[001] Cu tilt GBs, no specific influence of the furthermore determined orientation parameters (twist angle, second tilt angle), on the GB diffusion, is observed. This feature is discussed with respect to the particular dislocation network inherent in the present and previously investigated GBs.
- OSTI ID:
- 665190
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 15 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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