Design and development of patterned shape memory alloy thin film

Abstract

The research studied focuses on the development of patterned CuAlNi SMA bimorph on prestrained Kapton polyimide substrates. A flexible substrate such as Kapton polyimide is appropriate for obtaining a two-way memory effect. Shape memory alloy was deposited on a 75μm thick Kapton polyimide substrate. A patterned structure was fabricated in a planar fully deposited bimorph by means of laser fabrication method. Using electrical actuation configuration through Joule heating, the displacement of distinct patterns was explored at different voltages and different frequencies ranging from 1V to 4V and 0.25Hz -0.50 Hz respectively. The forward movement was accomplished by shape memory alloy effect and the return movement was due to the impact of Kapton polyimide substrate. Comparison of distinct patterns with the planar fully deposited has been done. The maximum displacement of 4.10 mm was investigated in a Deltoid patterned bimorph at 3V. The Shape Recovery Ratio of distinctly patterned bimorph was also investigated. The Austenite start temperature As and Austenite finish temperature Af was found to be 233.2 and 234.5 in °C respectively. furthermore, the morphological, structural and thermal behavior of the SMA bimorph was investigated in detail.