Dynastreem

From Tardis Wiki, the free Doctor Who reference

Dynastreem or Dynastream was a material used on Earth in the second half of the 20th century. It was believed undestructable, until the robot K1, built by professor Kettlewell, managed to disintegrate a safe made from it. (TV: Robot)

The Genetrix's balloon was made of dynastream. (PROSE: Sunset Over Venus)