Functional properties of NiTi nanofilm/Kapton composite

Abstract

The aim of the paper was to study the one-way and two-way shape memory effects in the NiTi nanofilm/Kapton composite. 500 nm film of the Ni50Ti50 alloy was deposited to Kapton by flash evaporation. After deposition, the NiTi layer was amorphous and the sample was held at a temperature of 350 - 400 °C for two hours in vacuum to crystallize the NiTi layer. As deposited sample as well as samples after heat treatment were bent around the mandrel with various diameters at room temperature and subjected to heating – cooling – heating through a temperature range of the martensitic transformations. It was shown that as-deposited sample did not demonstrate the recoverable stain variation. At the same time, the heat treated sample demonstrated the one-way shape memory effect on heating and a maximum recoverable strain was found to be 2 %. The two-way shape memory effect was not observed on further cooling and heating.