What term describes metals that can return to their original shape after deformation when heated?

• A. Shape memory alloys
• B. Advanced metal alloys
• C. Shape memory plastics
• D. Thermochromic Materials

Answer: (A)

Shape memory alloys.

These metals exhibit a shape memory effect caused by a reversible phase transformation between martensite and austenite. At low temperatures the alloy is in martensite and can be deformed. When heated, it transforms to austenite and the lattice rearranges back to its original shape, restoring the initial configuration. This effect is what lets metals return to their pre-deformed shape after heating.

The other options don’t describe this metal-specific, temperature-triggered shape recovery: shape memory plastics refer to polymers, thermochromic materials change color with temperature, and “advanced metal alloys” is a vague term that doesn’t capture the shape-recovery behavior.