Coarsening of the δ′ phase in aluminium-lithium alloys

• Published in: Philosophical magazine. A, Physics of condensed matter. Defects and mechanical properties Vol. 79; no. 4; pp. 859 - 872
• Main Authors: Noble, B., Bray, S. E.
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis Group 01.04.1999; Taylor and Francis
• ISSN: 0141-8610; 1460-6992
• DOI: 10.1080/01418619908210336

Transmission electron microscopy has been used to measure the size of the δ′ phase, and electrical resistivity to determine lithium concentration in the matrix, during coarsening of the δ′ phase. Application of the Lifshitz-Slyozov-Wagner theory of particle coarsening has enabled independent calculation of the δ′-α interface energy γ and the effective diffusivity D eff of lithium in aluminium during δ′ coarsening. For an alloy containing 7.6 at.% Li, γ is found to be 0.045 J m −2 and D eff at a temperature T is defined by the equation Increasing the lithium concentration of the alloy to 9.8 at.% had little effect on the activation energy of δ′ coarsening but it reduced the value of the pre-exponential factor.