Single-phase interdiffusion in Ni{sub 3}Al
- Kyoto Univ. (Japan). Dept. of Materials Science and Engineering
- Osaka Univ., Ibaraki (Japan). Inst. of Scientific and Industrial Research
Interdiffusion experiments have been made using single-phase diffusion couples of Ni{sub 3}Al over the temperature range from 1223 to 1473 K. The interdiffusion coefficient has been obtained from the concentration profiles measured by electron-probe microanalysis. The interdiffusion coefficient, {tilde D}, is 4--8 times larger than the tracer-diffusion coefficient of Ni, D{sup *}{sub Ni}, and increases with increasing Al concentration. For the stoichiometric composition, it is expressed as {tilde D} = 10{sup {minus}2.6{+-}0.7} exp({minus}305{+-}17 kJ/mol/RT) m{sup 2}/s. By applying the Darken-Manning equation, the diffusion coefficient of Al, D{sup *}{sub Al}, has been evaluated from {tilde D}, D{sup *}{sub Ni} reported in the literature and the thermodynamic factor evaluated from experimental data of the thermodynamic activity. The magnitude of D{sup *}{sub Al} thus estimated is smaller by a factor of 3--4 at 1400 K than that of D{sup *}{sub Ni} in the temperature range examined. For example, D{sup *}{sub Al} {approx} (0.25 {minus} 0.38)D{sup *}{sub Ni} at 1400 K.
- OSTI ID:
- 665192
- 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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