Shape Memory Alloy (Nitinol) has which property?

Shape Memory Alloy (Nitinol) has which property?

• A. Remembers its original shape and returns to it when heated
• B. Hardens permanently when heated
• C. Becomes more brittle with heat
• D. Loses shape when cooled

Answer: (A)

Shape memory behavior comes from a reversible phase change that lets the alloy revert to a remembered shape when heated. In Nitinol, at lower temperatures the material is in a martensite phase that can be easily deformed. When you heat it, it transforms to the austenite phase, which has the original, undeformed shape, and the material snaps back to that shape. This is why the statement about remembering its original shape and returning to it when heated is correct. The other options describe properties that don’t match how shape memory alloys actually behave (they don’t permanently harden with heat, don’t become more brittle with heat, and don’t lose shape simply by cooling).

Shape memory behavior comes from a reversible phase change that lets the alloy revert to a remembered shape when heated. In Nitinol, at lower temperatures the material is in a martensite phase that can be easily deformed. When you heat it, it transforms to the austenite phase, which has the original, undeformed shape, and the material snaps back to that shape. This is why the statement about remembering its original shape and returning to it when heated is correct. The other options describe properties that don’t match how shape memory alloys actually behave (they don’t permanently harden with heat, don’t become more brittle with heat, and don’t lose shape simply by cooling).