Role of vacancies in coprecipitation of δ′ – and S–phasesin Al–Li–Cu–Mg alloys
1986; Maney Publishing; Volume: 2; Issue: 4 Linguagem: Inglês
10.1179/026708386790328777
ISSN1743-2847
AutoresP.J. Gregson, H. M. Flower, C. N. J. Tite, A. K. Mukhopadhyay,
Tópico(s)Microstructure and mechanical properties
ResumoAbstractAbstractPrecipitation reactions in a series of Al–Li–Cu–Mg alloys, encompassing the composition ranges of the commercial Lital A and Lital B materials, have been studied to determine the role of solute and vacancy concentrations on homogeneous S-phase (Al2CuMg) precipitation. Homogeneous precipitation of S-phase only occurs when a critical combination of free vacancy and copper and magnesium supersaturation is achieved. Lithium reduces the free-vacancy concentration by strong binding between vacancies and lithium atoms or atom clusters. Precipitation of δ′ (Al3 Li) releases the bound vacancies and thereby promotes S-phase formation and, in extreme cases, vacancy condensation, producing dislocation loops.MST/350
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