AVENGERS (1963) #66

Long absent members Iron Man and Thor rejoin the Avengers after personal leave. The team must destroy an Adamantium cylinder created by mad scientist Myron MacLain. The unbreakable metal, Adamantium, makes it first appearance in this comic. The Avengers lend SHIELD a hand by testing out the strength of this new metal. It seems that even the powers of the Avengers isn’t enough to break this unbelievable material. Mysteriously, the Vision disappears during the testing.…