The deformation characteristics and the strengthening contribution of high purity AlLi alloys are studied under monotonic as well as under cyclic loading conditions on single‐ and polycrystalline specimens. The L12 ordered δ′ (Al3Li) precipitates are sheared by paired dislocations in underaged specimens and are by‐passed by Orowan looping when the particle diameter becomes larger than about 50 nm. Extended planar dislocation arrays are observed on isolated slip planes in underaged single crystals in consequence of local glide plane softening. The strengthening of the alloy can be described by the theory of order strengthening in the underaged condition. Good agreement between theory and experimental results obtained from both cyclic and monotonic testing can be reached by assuming a specific antiphase boundary energy of 165 mJ/m2 for the (111) planes.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics