Evaluation of two-step transformation in Ni-rich titanium-nickel alloys using thermal and internal friction analyses

ABSTRACT The use of Ti-Ni memory alloys covers several fields of application such as medicine, dentistry, actuators, sensors among others. Because of the thermomechanical behavior of these materials, they are an object of continuous studies and their properties are related to the occurrence of therm...

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Bibliographic Details
Published in:	Matéria Vol. 24; no. 3
Main Authors:	Virgolino, Fillipe Stephany de Souza, Santos, Tiago Felipe de Abreu, Oliveira, Carlos Augusto Nascimento, Gonzalez, Cezar Henrique, Sousa, Guilherme Gadelha de, Vilela, José Mário Carneiro, Andrade, Margareth Spangler
Format:	Journal Article
Language:	English
Published:	Laboratório de Hidrogênio, Coppe - Universidade Federal do Rio de Janeiro; em cooperação com a Associação Brasileira do Hidrogênio, ABH2 2019
Subjects:	CONSTRUCTION & BUILDING TECHNOLOGY MATERIALS SCIENCE, MULTIDISCIPLINARY METALLURGY & METALLURGICAL ENGINEERING calorimetry Ti-Ni shape-memory effect internal friction dilatometry
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Summary:	ABSTRACT The use of Ti-Ni memory alloys covers several fields of application such as medicine, dentistry, actuators, sensors among others. Because of the thermomechanical behavior of these materials, they are an object of continuous studies and their properties are related to the occurrence of thermoelastic martensitic phase transformations. The thermal analyzes were performed using dilatometry and differential scanning calorimetry to determine the temperatures that occurred transformations during the cooling and heating, as well as to evaluate the influence of the thermal treatments performed by dilatometry. The thermomechanical behavior was also evaluated by the internal friction that measured behavior damping considering the structural and microstructural changes. The calorimetry measurements indicated suppression of the R phase through decomposition of precipitates of Ti3N4after the thermal treatments, that were corroborated by dilatometry and microhardness. This phase was also studied by the technique of internal friction, which showed that the mechanical damping coefficient increased as a function of temperature, due to the movement of the defects induced by tension.
ISSN:	1517-7076 1517-7076
DOI:	10.1590/s1517-707620190003.0766