Effect of Spun Velocities and Composition on the R‒phase and Thermomechanical Behavior in Ti‒Ni Ribbons Electrically Heated

AUTOR(ES)

Cuellar, Enrique López, Mendoza, Esaú Nuñez, Araújo, Carlos José De, Walle, Beatriz Cristina López, Otubo, Jorge, Gonzalez, Cezar

FONTE

Mat. Res.

DATA DE PUBLICAÇÃO

08/04/2016

RESUMO

This work deals with structural, electrical and mechanical characterization of Ti‒50.13Ni and Ti‒49.62Ni (at.%) shape memory alloys (SMAs) fabricated at different circumferential wheel velocities. The effect of wheel velocity, chemical composition and heat treatments are investigated. The characterization of crystallographic phases of the Ti‒Ni ribbons was carried out using X-ray diffraction. Electrical resistance variations as function of temperature (∆R/R %) were analyzed using a non-commercial technique, which consists in a thermal-adjustable bath apparatus revealing the temperatures of B2→R→B19´ two stage transformation, whereby the presence of R‒phase can be definitively confirmed. The Stress-Assisted Two-Way Memory Effect was measured by an own designed apparatus with an Linear Variable Differential Transformer captor and a current controlled heating, and results indicate that the as-spun condition, promotes the Stress-Assisted Two-Way Memory Effect. On the other hand, increments in Ni content tend to decrease transformation temperatures and high wheel velocities help to the R‒phase formation.

Documentos Relacionados

• Heat treatments and thermomechanical cycling influences on the R-phase in Ti-Ni shape memory alloys
• Effect of Spun Velocities and Composition on the Microstructure and Transformation Temperatures of TiNi Shape Memory Ribbons
• Electro-thermomechanical characterization of Ti-Ni shape memory alloy thin wires
• Thermomechanical Analysis on Ti-Ni Shape Memory Helical Springs Under Cyclic Tensile Loads
• Analysis of the transformations temperatures of helicoidal Ti-Ni actuators using computational numerical methods