Processo e caracterização de ligas Ti-Ni-Cu com efeito de memória de forma solidificadas rapidamente.

Abstract

Alloys with shape memory effect have immense potential for applications in robotics, automotive and aeronautics industry, medicine and in the production of miniaturized actuators. The aim of this study was to investigate, develop and manufacture materials with shape memory effect of Ti-Cu-Ni alloys in the form of micrometer tapes produced by Melt Spinning. The methodology used for the production of Ti-Cu-Ni alloys by fusion plasma (Plasma Skull Push-Pull), and manufacturing tapes used the technique of rapid solidification injection of liquid metal into the copper wheel speeds 38 and 50 m/s. alloy and Ti-Ni-Cu ribbons were characterization by: DSC, SMRT, XRD, SEM. Initially prismatic bars of Ti-Ni50-x-Cux (x = 3,4,5,6,7 at.Cu%) had been produced by plasma fusion. With the rapid solidification is obtained tapes with thicknesses between 30 to 45 µm with the variation of the speed of the wheel covers 38 and 50 m / s the melt spinning. XRD tests reveal the presence of the B19' in gross phase alloy melting temperature. The alloys showed phase transformations in single stage B2↔B19`. The transformation temperatures of the alloy Ti-Cu-Ni decrease with the increase of Cu. We conclude that the temperatures of martensitic transformation (Ms) of Ti-Ni-Cu ribbons decreases with decreasing grain size, and hysteresis values and enthalpy decreases when high rates of super-cooling are achieved in Melt Spinnig.