Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5436186 | Acta Materialia | 2017 | 13 Pages |
The Al-Ag system is thought to be a well-understood model system used to study diffusional phase transformations in alloys. Here we report the existence of a new precipitate phase, ζ, in this classical system using scanning transmission electron microscopy (STEM). The ζ phase has a modulated structure composed of alternating bilayers enriched in Al or Ag. Our in situ annealing experiments reveal that the ζ phase is an intermediate precipitate phase between GP zones and γâ². First-principles calculations show that ζ is a local energy minimum state formed during Ag clustering in Al. The layered structure of ζ is analogous to the well-known Ag segregation at the precipitate-matrix interfaces when Ag is microalloyed in various aluminium alloys.
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