Lithium diffusion in aluminum-lithium alloy 2090 clad with 7072

Autor: Papazian, J. M., Schulte, R. L.
Zdroj: Metallurgical and Materials Transactions A; January 1990, Vol. 21 Issue: 1 p39-43, 5p
Abstrakt: The loss of lithium during solution heat treatment of alloy 2090 clad with approximately 100 μm of 7072 was investigated. Lithium concentration profiles in the alloy were measured using a nuclear reaction analysis technique after samples had been subjected to various solution heat treatments. The results showed that the cladding-base metal interface provided no impediment to lithium diffusion and that the rate of lithium diffusion in the cladding was similar to its rate of diffusion in the base metal. A lithium-rich oxide was formed on the external surface, but the concentration profiles showed that the effective lithium concentration at the surface was near zero. Thus, lithium in the bulk experienced a maximum concentration gradient and diffused to the surface as rapidly as possible. Despite the absence of any lithium diffusion barrier in the cladding, the initial rate of lithium loss is much less than in bare material. The cladding provides effective protection from lithium loss, and the rate of loss in clad materials only approaches that of bare materials after approximately 4 hours.
Databáze: Supplemental Index