The most common shape‑memory fibers are made from nickel‑titanium (Nitinol), a thermomechanical alloy. Other alloys such as copper–aluminium–silicon or steel–nickel can also exhibit SME, but they are less frequent in fiber form. Polymeric shape‑memory fibers are emerging; they rely on polymer networks that can be cross‑linked or incorporate shape‑memory polymers (SMPs). These materials can respond to heat, osmotic pressure, or even solar radiation.
The manufacturing process typically involves drawing the base metal or polymer into a fine filament, followed by heat‑treating to refine the grain structure. The fibers can be engineered in straight or pre‑deformed shapes, such as helices or zigzags. Reinforcement can be provided by embedding the fibers in a matrix, allowing the SME to be harnessed in composites or textiles.
Applications span several fields. In medical devices, shape‑memory fibers serve as actuators in stents, guidewires, and minimally invasive tools. In robotics, they are used as compliant, lightweight actuators capable of smooth motion. In aerospace and automotive engineering, shape‑memory fiber‑reinforced composites can adjust their geometry for aerodynamic performance or deployable structures. In consumer products, smart textiles with embedded shape‑memory fibers can adapt to body temperature or enable self‑retracting designs.