A determination of vacancy properties in AuNi solid solutions, via analysis of stress-induced and short range ordering kinetics
✍ Scribed by E. Balanzat; M. Halbwachs; J. Hillairet; C. Mairy; P. Guyot; J.P. Simon
- Publisher
- Elsevier Science
- Year
- 1983
- Weight
- 979 KB
- Volume
- 31
- Category
- Article
- ISSN
- 0001-6160
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✦ Synopsis
Vacancy properties were studied in an a-Au-30 at.% Ni solid solution, with use of electrical resistivity and mechanical after-effect measurements, for the monitoring of short-range and stress-induced ordering kinetics, respectively. Both thermodynamic& equilibrium concentrations and quenched-in super-saturations were considered for the vacancy defects. It is shown that, due to the inherent sensitivity of the methods used, valuable information about the vacancy parameters and related atomic mobility can be inferred from analysis of the ordering rate at low temperatures, that is in conditions of non~~iib~um for the a-phase. The respective activation energies for self-diffusion and vacancy migration which were derived from the rate temperature dependence are 1.85 and 1.10 eV, respectively. These values yield a consistent fit to the ordering pattern observed during quench and isochronal anneal cycIea. Information about vacancy sink densities and life-times was inferred also. The salient feature of the results is that, while the atom jump rate is not substantially modified by alloying, vacancy mobility is markedly slowed down; conversely the vacancy formation energy appears to be strongfy decreased. A Au-5 at.% Ni alloy for which the a-phase is stable at all temperatures was studied also. ' D.