Caracterização de uma fita de Ti45Ni48Cu7 com efeito de memória de forma para aplicação em uma microválvula.

Abstract

In this work is presented the characterization of Ti45Ni48Cu7 alloy with shape memory effect to be used in a microvalve to fluid control by Joule effect. To this purpose, it was obtained a portion fused mass with controlled rates of 45%Ti48%Ni7%Cu weight was transformed into ribbons by melt spinning process at a speed of 38 m/s. The ribbons obtained were subjected to thermal relaxation process in order to promote the elimination of internal defects. Then, to obtain the phase transformation temperatures and the energy enthalpy, the ribbons were submitted to Differential Scanning Calorimetry (DSC). Following, the dynamic mechanical analysis (DMA) test was done to record the percentage increase in the modulus of elasticity of the ribbon submitted to different temperatures. By submission of the ribbon to a thermal bath it was possible to plot the electrical resistance versus the pattern desired temperature and thus the ribbon to be used in the microvalve theorized by Bellouard was chosen. To demonstrate experimentally that this tape would be able to work normally in the product for which it was theoretically suggested, an experimental electrical resistivity versus temperature graph was plotted. Additionally, from the three-dimensional design and the 3D and internal microvalve geometry, a computer simulation based on static structure CFX tool with the ANSYS® Workbench V14 were performed and displayed, enabling the visualization of the Newtonian fluid movement within the microvalve.