The circular shield most associated with Captain America made its debut in Captain America Comics #2 (April 1941). A convex metal disc approximately 2.5 feet (0.76 m) in diameter, it is indestructible and has remained his most constant shield over the decades.
Again through retroactive continuity, it is established that the shield was presented to Rogers by President Franklin D. Roosevelt.[1] The shield is created by a fictional American metallurgist named Dr. Myron MacLain, who had been commissioned by the US government to create an indestructible armor material to aid the war effort. MacLain experiments with vibranium, an alien metal found only in Wakanda that has unique vibration absorption properties.
Captain America vol. 5, #5 (May 2005). Cover art by Steve Epting.During one of his experiments to fuse vibranium with an experimental iron alloy,[2] MacLain falls asleep and awakens to find the experiment a success. However, this is due to an unknown catalyst entering the process during his slumber, and he is unable to duplicate the result. The vibranium-iron alloy mix is then poured into a mold for a tank's upper hatch to create the disc shape and painted to become Captain America's symbol.
Rogers' indestructible shield was long referred to, even in continuity, as being composed of an adamantium-vibranium alloy. This contradicted earlier established continuity, as adamantium is only developed after Rogers is revived from suspended animation, during MacLain's later experiments to try and duplicate the material of the shield. Adamantium makes its first appearance in Marvel Comics in Avengers Vol. 1 #66, July 1969.
The adamantium-vibranium error first appears in the Captain America entry in the Official Handbook of the Marvel Universe (the composition of the shield is accurately described in the adamantium entry as "vibranium-iron") and was propagated in several subsequent stories by writers using the Handbook as a reference. An attempt to correct this was made in Captain America #303–304 (March–April 1985), which establishes that the shield is made of vibranium and an "experimental iron alloy", but that did not prevent the repetition of the "adamantium-vibranium" description over the years.
The vibranium in the shield is what absorbs virtually all of the kinetic impact from any blows that the shield receives, allowing it to withstand incredible amounts of force without injuring Rogers in the process. The vibranium is also a factor in the way Rogers throws his shield: he often uses it to ricochet around a room and strike various opponents with little loss of velocity in its forward movement after each impact.
When Rogers returns from suspended animation, Tony Stark "improves" the shield by incorporating electronic and magnetic components in it so that Rogers could even control it in flight. However, Rogers soon discards the additional components because he finds that it upsets the balance of the shield when thrown, which is Rogers' ultimate preference.
During his early years in the Avengers, when it is not firmly established that the discus-shaped shield is indestructible, the shield is destroyed or lost several times in the comics, to return with no explanation. It is eventually retconned that these are steel replicas, with the actual shield being borrowed by Stark for analysis and returned to Rogers later.[citation needed]
After Rogers' death, Stark takes over custody of the shield, with one replica on display in a museum, and another replica being buried with Rogers. The real one is kept by Stark to be used by the new Captain America, whenever they deem it appropriate to train a new one. After failing to find a S.H.I.E.L.D. agent capable of throwing it properly, Stark offers the shield to Clint Barton, who does manage to throw it but declines Stark's offer to become the new Captain America. The shield is subsequently stolen by the Winter Soldier, who did not want anyone else to carry the shield. Inevitably, in an effort to honor Rogers' last wishes, Stark offers to let the Winter Soldier (Bucky Barnes) keep the shield, and to serve as the new Captain America. Bucky accepts. This offer is made "off the books," and only the two of them, the Black Widow, and the Falcon, are aware of the situation.
Cap's shield has been damaged plenty of times.
