Publications by Iva Tkalcec Vâju

Book of Abstracts from the 20th International Conference on Internal Friction and Mechanical Spectroscopy (ICIFMS20)

Daniele Mari, Iva Tkalcec Vâju, Lucas Eric Jacques Degeneve

Trans Tech Publications Ltd2025

MECHANICAL SPECTROSCOPY OF ORDERED BINARY Au-Cu

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju

We have studied a binary Au-Cu single crystal by mechanical spectroscopy. Upon very slow cooling from high temperatures, additional relaxation peaks arise at lower frequencies in isothermal spectra after the disappearing of the Zener peak below 665 K due t ...

Polska Akad Nauk, Polish Acad Sciences, Inst Metall & Mater Sci Pas2015

Grain boundary relaxation in yellow gold bi-crystals

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju, Ann-Kathrin Audren

The mechanical loss spectrum of a yellow gold bi-crystal is presented and analyzed in detail. The relaxation strength is monitored as a function of several geometrical parameters such as sample width, length and thickness. It is found that the relaxation s ...

Elsevier2015

GRAIN BOUNDARY RELAXATION IN Bi-CRYSTALS: MECHANICAL SPECTROSCOPY AND MOLECULAR DYNAMICS SIMULATIONS

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju, Ann-Kathrin Audren

Different Au-Ag-Cu samples have been studied by mechanical spectroscopy. Both polycrystals and bi-crystals show a relaxation peak at 800 K, accompanied by an elastic modulus change. Since this peak is absent in single crystals it is related to the presence ...

Polska Akad Nauk, Polish Acad Sciences, Inst Metall & Mater Sci Pas2015

Theoretical modelling of grain boundary anelastic relaxations

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju, Ann-Kathrin Audren

Grain boundary stress relaxation in Au polycrystals and single crystals has been studied by mechanical spectroscopy. A relaxation peak related to grain boundaries is observed at 620 K. Molecular dynamics simulations on Au are performed in order to illustra ...

Pergamon-Elsevier Science Ltd2014

Recrystallization and grain boundary formation in an 18-carat gold alloy studied by mechanical spectroscopy

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju, Ann-Kathrin Audren

Heavily deformed 18-carat yellow gold samples show a recrystallization peak at 700 K during the first heating. The mechanical loss spectrum of polycrystals shows a relaxation peak at about 780 K, which is absent in single crystals made from the same alloy. ...

Trans Tech Publications Ltd2013

New In-Pd mechanical loss peak in ternary gold alloys

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju, Ann-Kathrin Audren

A point defect relaxation peak has been observed in a ternary 18-carat gold alloy with the composition Au62.5Pd32.5In5. It shows a Curie Weiss dependence on the temperature, as is commonly observed for a Zener peak. However, the peak is absent in the binar ...

Pergamon-Elsevier Science Ltd2013

Grain boundary formation stages in a deformed yellow gold single crystal studied by mechanical spectroscopy

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju, Ann-Kathrin Audren

A monocrystalline 18-carat yellow gold sample is deformed stepwise from 2% to 12% at room temperature. The mechanical loss spectrum is recorded and analysed. At low deformations the exponential high temperature background increases. At a critical deformati ...

Elsevier Science Sa2013

Grain boundary relaxation and grain growth in 18-carat yellow gold alloy

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju, Ann-Kathrin Audren

A high-temperature anelastic relaxation peak in the mechanical loss spectrum of 18-carat yellow gold polycrystals is analysed and interpreted as due to grain boundary sliding accommodated predominantly by elastic deformation of the grains. The characterist ...

2012

Investigation of hydrogen storage in carbon nanotube-magnesium matrix composites

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju

Magnesium (Mg) and magnesium nickel (Mg-23.5 wt%Ni) reinforced with multiwalled carbon nanotubes (CNTs) were processed by powder metallurgy and then charged with hydrogen by annealing at 620 K under a pressure of 0.4 MPa of hydrogen. Mechanical spectroscop ...

2009

Mechanical spectroscopy of 18-carat AuCuPd white gold alloys

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju, John Hennig

The mechanical loss and dynamic modulus temperature spectra of two 18-carat white gold alloys, Au58%Cu24%Pd18% without (grade A) and with alloying additions (grade B), were measured in the 400-1000 K temperature range. A peak interpreted as a Zener relaxat ...

2009

Tempering effects on three martensitic carbon steels studied by mechanical spectroscopy

Robert Schaller, Daniele Mari, Iva Tkalcec Vâju

Tempering effects have been studied in three martensitic carbon steels by mechanical spectroscopy. The mechanical-loss spectra present a relaxation peak similar to the Snoek-Koster peak in ferrite. The peak amplitude decreases upon tempering, indicating a ...

2008