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Fatigue resistance of dual-phase NiTi wires at different maximum strain amplitudes

2019; Elsevier BV; Volume: 125; Linguagem: Inglês

10.1016/j.ijfatigue.2019.03.040

1879-3452

Jéssica Dornelas Silva, Pedro Damas Resende, Paula Ribeiro Garcia, Natália Isabel de Azevedo Lopes, Leandro de Arruda Santos, Vicente Tadeu Lopes Buono,

Titanium Alloys Microstructure and Properties

Known by their functional shape memory and superelastic properties, aligned with an excellent biocompatibility, near equiatomic NiTi alloys are vastly used as biomaterials. In various applications, such as endodontic files and cardiovascular stents, NiTi components are subjected to aggressive fatigue conditions, making fatigue resistance and mechanisms relevant to the materiaĺs development. In this context, heat treatments can be a powerful tool to improve the fatigue life and efforts have been made to understand and predict the fatigue behavior of these alloys in different conditions. In this work, initially superelastic near equiatomic Ni-rich wires were heat-treated at 400 °C and 450 °C and the ε × Nf curve was obtained. Rotating-bending strain-controlled fatigue tests were performed at maximum strains varying from 1% to 5% at 37 °C. The results showed that both samples exhibited large fatigue resistance and similar fatigue behavior through the different maximum strains, and thus, treatments within the range of temperature from 400 °C to 450 °C are recommended to obtain NiTi components with high fatigue life for large maximum strain amplitudes.