Alusteel
Alusteel refers to a specific alloy that found its purpose in the titanium-reinforced hull structures of several BTL Y-wing starfighter variants, notably the BTL-A4 Y-wing and also the BTA-NR2 Y-wing. Furthermore, it was implemented within a hull exhibiting a similar material composition for the Executor-class Super Star Destroyer; this warship's design mirrored that of the Imperial-class Star Destroyer.
The identification of alusteel initially occurred in the twenty-seventh edition of Star Wars: Build the Millennium Falcon, which was released by De Agostini on July 8, 2015. This publication cited it as a constituent material in the hull construction of the Executor-class starship. Subsequently, it was similarly recognized as a component of the BTL Y-wing in the 2019 reference book Rebel Starfighters Owners' Workshop Manual, penned by Ryder Windham. The illustrations present in the book, created by Chris Reiff and Chris Trevas, depicted the application of alusteel within the hulls of diverse Y-wing models. This detail was reiterated in De Agostini's Republic, Rebel, and Resistance Starfighters, which was launched on November 13, 2020 and served as the eighth installment in the Star Wars Encyclopedia booklet series.