Captain America's shield is composed of an alloy of Adamantium-Vibranium & Thor's Mjölnir is forged with Enchanted Uru.


Captain America's shield is composed of an alloy of Adamantium-Vibranium & Thor's Mjölnir is forged with Enchanted Uru.


In the Marvel Canon, neither Mjölnir or Captain America's shield are "indestructible", as evidenced by their repeated destruction.
Captain America's shield, which is an Adamantium-Vibranium alloy has been broken five times in the history of comics. The Molecule Man once destroyed the shield (along with Mjolnir, Namor's indestructible armor, and the Silver Surfer's board) by unmaking them on the molecular level. Klaw and Dr. Doom (both amped by the power of The Beyonder) damaged the shield on separate occasions. Thanos, wielding the Infinity Gauntlet, effortlessly shattered the shield with a backhand.
King Thor's Eyebeams cut through Captain America's shield in the Alternate Universe comic "All Star Superman Vs Odin Force Thor".

The Destroyer cut Mjolnir in half in 'Mighty Thor Vs The Destroyer'
