We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Study of isothermal δ′ (AlLi) precipitation in an Al-Li alloy by thermoelectric power.
- Authors
Gutiérrez-Urrutia, I.
- Abstract
We study the isothermal δ′ (AlLi) precipitation kinetics in an Al-2.3 wt% Li-0.1 wt% Zr alloy by means of the measurement of the thermoelectric power (TEP) in the temperature range between 120 and 180 °C. We obtain that the nucleation-and-growth stage of δ′ precipitation reaction can be well described by the Johnson-Mehl-Avrami-Kolmogorov (JMAK) relation. This result suggests that the JMAK relation provides a good description of the impingement effect of growing δ′ precipitates where interactions mainly occur on neighbouring precipitates. The activation energy associated to the nucleation-and-growth stage calculated from the JMAK fit is 52 ± 1 kJ/mol. The small activation energy obtained is ascribed to the presence of a large amount of excess vacancies quenched-in from the ageing temperature, inherent to the experimental conditions of the measurement of the TEP, reducing the activation energy to a value close to the vacancy migration energy in aluminium (45-65 kJ/mol). The Avrami exponent of this stage ranges between 1.5 and 1.65. These kinetic parameters indicate that δ′ particles grow via a three-dimensional vacancy migration-controlled mechanism.
- Subjects
ALUMINUM alloys; THERMOELECTRICITY; TRANSMISSION electron microscopy; NUCLEATION; DYNAMICS
- Publication
Journal of Materials Science, 2011, Vol 46, Issue 9, p3144
- ISSN
0022-2461
- Publication type
Article
- DOI
10.1007/s10853-010-5195-8