Abstract
The martensitic and reverse transformation temperatures of TiNi shape memory alloy (SMA) are directly related to its bending rigidity. In this study, we developed a new fabrication process that combines powder metallurgy and plastic working to obtain a functionally graded TiNi SMA stripe that varies in bending rigidity from high to low along the stripe axis. First, a multilayered TiNi green compact in which the Ti-Ni compositions varied layer by layer was sintered using a spark plasma sintering process; the compact was then hot and cold rolled into stripes. We investigated the functionally graded properties of the local deformation properties of the resulting rolled thin stripes. Using stripes that already exhibit functionally graded properties, we observed that the transformation temperatures of hot- and cold-rolled TiNi SMA stripes are also functionally graded. As a result, the deformation behaviors of the rolled stripes differ depending on the Ni content at a given position.
