AVALIAÇÃO DO INTERVALO DE TRANSIÇÃO TÉRMICA DE LIGAS DE NÍQUEL-TITÂNIO TERMOATIVADAS

Abstract

The effect of shape memory Nickel-Titanium wire is related to its phase transition temperature. The objective of this study was to evaluate the range of thermal transition of seven strands of Nickel-Titanium term actives size 0,019" x 0,025", featuring the temperature Austenitic start (As), Austenitic final (Af), Martensite Start (Ms), Martensitic final (Mf) and the Rhombohedralphase (R and Rf), present. Wires Nitinol Termoativado (Aditek), NeoSentalloy F200 (GAC), ThermoPlus (Morelli), Copper NiTi 35 °C (Ormco), Flexy Thermal 35 °C (Orthometric) Superthermal Nickel Titanium Arches (Orthosource) and Heat Activated NiTi (Highland Metals) were evaluated using the method Differential Scanning Calorimetry (DSC). Graphics exothermic curves (martensite) and endothermic (austenite) were generated by the machine software, as well as the values of the thermal transition temperature and enthalpy of each reaction. The temperature of phase transformation and behavior of these transformations differ between trademarks tested, resulting in a variable shape memory effect.