Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
MECHANICAL BEHAVIOR OF Ni-Ti SMA HELICAL SPRINGS MANUFACTURED BY INVESTMENT CASTING
Submission Author:
jose joelson de melo santiago , PB , Brazil
Co-Authors:
Paulo César Sales da Silva, Jackson Simoes, Carlos Jose de Araujo, jose joelson de melo santiago
Presenter: Jackson Simoes
doi://10.26678/ABCM.COBEM2017.COB17-2902
Abstract
Shape Memory Alloys (SMA) are active metallic materials that have being increasingly studied because the potential applications due to their functional properties of recovering original shape by heating after pseudo plastic deformation. In this context, SMA helical springs can be used as actuators or sensors in several areas. Thus, this work aims to perform thermal and mechanical characterization of Ni-Ti SMA helical springs produced by investment casting process of induction melting followed by centrifugal casting (ICC). Thermal characterization of the springs was performed by Electrical Resistance as a function of Temperature (ERT), while the mechanical characterization in static and dynamic regimes was performed in an Instron Model E10000 machine. The results of thermal analysis by ERT showed that the helical Ni-Ti springs have phase transformation corresponding to the superelastic effect (SE) at room temperature (~25±2 °C). The reversible deformations under uniaxial tensile were of the order of 80% and the dynamic tests showed that the mechanical properties vary according to the frequency and deformation amplitude. At last, it was verified that the Ni-Ti SMA helical springs produced by IMC process present functional characteristics, which are suitable for superelastic applications such as springs manufactured by conventional processes.
Keywords
Shape Memory Alloys, investment casting, Nitinol, helical springs
