Wapometal

Wapometal is a special kind of metal discovered by Wapol when he was turning garbage into toys during his mini-story, manufactured via his Baku Baku no Mi powers. It was this metal that turned him from a homeless bum into a very wealthy CEO of a toy company. His wapometal toys were so successful, the World Nobles granted him a new kingdom as a reward.

Franky used wapometal for his Iron Pirate Franky Shogun. It is a shape-memory alloy that can be restored to its preconfigured shapes, being used to create merger modes in the components of the Iron Pirate Franky Shogun.

Trivia

 * Though it isn't stated by name, the Vinsmoke Family Raid Suits are also said to be made from a shape-memory alloy, and like the Franky Shogun, have proven to be fire-resistant.