Publications de Robert Schaller

MECHANICAL SPECTROSCOPY OF ORDERED BINARY Au-Cu

Daniele Mari, Robert Schaller, 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

Daniele Mari, Robert Schaller, 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

Daniele Mari, Robert Schaller, 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

Applications Of Mechanical Spectroscopy To Industrial Materials

Robert Schaller

The paper is a review of original results, which were obtained by mechanical spectroscopy in the development of industrial materials, such as grey cast iron (damping capacity), aluminum alloys (recrystallization), nickel alloys (grain boundary embrittlemen ...

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

High/room temperature mechanical properties of 3Y-TZP/CNTs composites

Robert Schaller, Mehdi Mazaheri

Spark Plasma Sintering (SPS) method was practiced, in the current investigation, to obtain fully dense materials with an excellent dispersion of MWCNTs (Multi-walled Carbon Nanotubes) within the matrix. Scanning and transmission electron microscopy microgr ...

Elsevier Sci Ltd2014

Theoretical modelling of grain boundary anelastic relaxations

Daniele Mari, Robert Schaller, 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

Daniele Mari, Robert Schaller, 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

Daniele Mari, Robert Schaller, 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

Daniele Mari, Robert Schaller, 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

Daniele Mari, Robert Schaller, 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