LIA FOOK, N. C. M.; http://lattes.cnpq.br/0435818189426991; LIA FOOK, Nathália Cristina Morais.
Résumé:
The Ni-Ti alloys have enabled the improvement in many projects from the traditional
engineering and from the medical and orthodontic areas with their unique properties of
superelasticity and shape memory effect. In recent decades, researches and analysis for
applying these alloys have become increasingly more specific, tending to studies on
micro and nano actuators targeting applications in medical and orthodontic devices and
in electromechanical microsystems. Thus, the welding processes have become important
allies by promoting the union between shape memory alloy actuators (SMA) with
similar and dissimilar ones, which is one way of increasing the useful applications of
available materials, especially biomaterials. In this context, this study aimed at analyzing
the corrosion resistance in the weld region obtained by autogenous TIG micro welding in
Ni-Ti superelastic wires with thermo-active Ni-Ti wires in a solution that simulates human
saliva. The welded wires also Soldiers wires also undergone heat treatment made based on a
factorial design 3. The characterization of the original and welded wires (with and
without heat treatment) was performed using differential scanning calorimetry (DSC)
and scanning electron microscopy (SEM) tests and also regarding its resistance to
corrosion. The results revealed that the TIG welding process used in this work generated
welds of excellent quality, showing a good resistance to corrosion in the electrolyte that
simulates human saliva. The experimental design used to investigate the influence of
temperature and time of heat treatment in corrosion results generated a great experiment
with temperature of 350 °C and time in the range of 20 to 40 minutes. These results
were confirmed by means of electrochemical impedance spectroscopy tests.
