Title

STUDY OF Ti₃₂Zr₁₈Ni₅₀ ALLOY THROUGH INTERNAL FRICTION AND ELASTIC MODULUS

STUDY OF Ti₃₂Zr₁₈Ni₅₀ ALLOY THROUGH INTERNAL FRICTION AND ELASTIC MODULUS

Authorship

COLORADO, HENRY; SALVA, HORACIO; CHAVES, CÉSAR; VÉLEZ, JUAN; GHILARDUCCI, ADA

COLORADO, HENRY

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SALVA, HORACIO

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CHAVES, CÉSAR

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VÉLEZ, JUAN

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GHILARDUCCI, ADA

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DOI

10.5151/2594-5327-2856

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Abstract

Internal Friction (IF) and shear modulus (G) measurements were carried out in a Ti₃₂Zr₁₈Ni₅₀ alloy to study the effect of martensitic transformation on hydrogenation properties. The temperatures of martensitic transformation (Ms and Mf) and austenitic transformation (As and Af) were determined. The results were compared to those obtained by Electrical Resistivity (ER) and Differential Scanning Calorimetry (DSC) techniques. The measurements of internal friction were performed in a sub-resonant torsion pendulum and in vibrant sheet equipment. The experiments showed two peaks of internal friction, one associated to dislocations relaxation (P1) and the other to phase transformations (P2). The microstructure characterization was done by Scanning Electron Microscopy (SEM). The phase (Ti, Zr)₂Ni was found preferably precipitated in grain boundaries. Some experiments were carried out in specimens with previous plastic strain (in torsion) and another set of samples was tested in a hydrogen atmosphere. With increasing plastic strain, the amplitude of the peak associated to dislocations decreased, which is suggested to be related to an increase of interaction of dislocations with anchorages. Hydrogen addition during the tests led to an increase in the temperature of maximum internal friction.

Internal Friction (IF) and shear modulus (G) measurements were carried out in a Ti₃₂Zr₁₈Ni₅₀ alloy to study the effect of martensitic transformation on hydrogenation properties. The temperatures of martensitic transformation (Ms and Mf) and austenitic transformation (As and Af) were determined. The results were compared to those obtained by Electrical Resistivity (ER) and Differential Scanning Calorimetry (DSC) techniques. The measurements of internal friction were performed in a sub-resonant torsion pendulum and in vibrant sheet equipment. The experiments showed two peaks of internal friction, one associated to dislocations relaxation (P1) and the other to phase transformations (P2). The microstructure characterization was done by Scanning Electron Microscopy (SEM). The phase (Ti, Zr)₂Ni was found preferably precipitated in grain boundaries. Some experiments were carried out in specimens with previous plastic strain (in torsion) and another set of samples was tested in a hydrogen atmosphere. With increasing plastic strain, the amplitude of the peak associated to dislocations decreased, which is suggested to be related to an increase of interaction of dislocations with anchorages. Hydrogen addition during the tests led to an increase in the temperature of maximum internal friction.

Keywords

Internal Friction, Inverted torsion pendulum, Shear modulus

Internal Friction, Inverted torsion pendulum, Shear modulus