EFFECT OF SOLUBILIZATION ON THE MECHANICAL PROPERTIES OF NITI TUBES
COSTA, T. F.1; MUTERLLE, P. V.1; Arthur Pinheiro Barcelos1
1 UNB
doi:10.20906/CPS/CILAMCE2017-0391
Resumo
NiTi alloy presents particular properties: they can recover large deformations by temperature variation (memory effect) or by discharge (pseudoelastic effect). Due to these properties, this alloy presents itself promising at structures control. This paper examines the influence of martensite solubilizations on mechanical properties of NiTi alloy (55%w.p. Ni and 45%w.p. Ti). To obtain the properties of the alloy was used Vickers microhardness test, Differential Scanning Calorimetry (DSC), X-Ray Diffraction and Tensile Test according to ASTM F-2516. First, the results of the DSC as received NiTi tubes confirmed the presence of the martensitic phase at room temperature. Then the specimens were heat treated at 500°C for 60 minutes and water cooled at room temperature. After treatment, the martensitic transformation temperatures decreased and only austenitic phase was present at room temperature. The heat treatment reduced 22.6% the value of microhardness. On tensile tests it was observed that the specimen treated obtained 1% of residual deformation.
Palavras-chave: NiTi; Shape memory alloy; Pseudoelastic; Solubilized martensite; Phase Transformation