Different from round wires, the nitinol flat wire has a rectangular cross-section. Depends on the shape, it can also be called belts, or rectangular wire.
An experimental investigation on performance of NiTi-based shape memory alloy 4D printed actuators for bending application
Automated shape-transformable self-solar-tracking tessellated crystalline Si solar cells using in-situ shape-memory-alloy actuation
Nitinol Innovation - Kellogg's Research Labs (Technical Intro Slide)
Nitinol Wire Forming and Manipulation for Custom Components Meeting Customer Requirements
Structure, wettability, corrosion and biocompatibility of nitinol treated by alkaline hydrothermal and hydrophobic functionalization for cardiovascular applications - ScienceDirect
Nitinol Wire (Shape Memory, Superelastic Alloy)
Kellogg's Research Labs, High Temp 180°F (80°C), 0.020 (0.5mm) Shape Memory Nitinol wire, 5 feet : : Electronics
Technical Articles - Kellogg's Research Labs
.com: Kellogg's Research Labs, Standard Temp 115°F (45°C), 0.010 (0.25mm) Shape Memory Nitinol Wire, 5 feet : Industrial & Scientific