Structural relationship between one-dimensional crystals of Guinier-Preston-Bagaryatsky zones in Al-Cu-Mg alloys

Highlights: → This work identifies and fully describes a new type of 1D-crystalof the GPB zone family based on high-resolution Scanning TransmissionElectron Microscopy. → The observations enable to generalize the relationship between the1D crystals of GPB zones. → Ab-initio calculations show that the newly identified 1D-crystalhas a formation energy that is comparable to the larger GPB zonescrystals. -- The crystal structure of Guinier-Preston-Bagaryatsky (GPB) zones in Al-Cu-Mg alloys is unique, consisting of agglomerated one-dimensional (1D) crystals. This work identifies and fully describes a new type of 1D crystal of the GPB zone family based on high-resolution scanning transmission electron microscopy. The observation enables the structural relationship between the possible 1D crystals to be generalized. Ab initio calculations show that the newly identified 1D crystal has a formation energy that is comparable to larger types, and much more favorable than face-centered-cubic-based models.