Superelastic Nitinol wire & shape memory Nitinol wire are both types of nickel-titanium alloy wire, but they have different properties and used in different ways. Superelastic Nitinol wire exhibits a property known as superelasticity, which allows it to recover its shape after being deformed by a small amount, and return to its original shape when the stress is removed. It does not require any external thermal energy to change its shape. Shape memory Nitinol wire, on the other hand, exhibits a property known as shape memory, which allows it to return to a specific, pre-programmed shape after being deformed, but it requires external thermal energy, such as heating, to change its shape.