Publications by Ann-Kathrin Audren

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

Grain Boundary Relaxation in 18-carat Gold Alloys

Ann-Kathrin Audren

Grain boundaries (GBs) play an important role for the mechanical properties of metals. In addition to dislocation motion inside the grains, some metal alloys deform along the GBs at high temperatures. GBs can also be the cause of a brittle behaviour of som ...

EPFL2014

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

Generating mu and B mu in models with Dirac gauginos

Ann-Kathrin Audren

We consider the extension of the Minimal Supersymmetric Standard Model by Dirac masses for the gauginos. We study the possibility that the same singlet S that pairs up with the bino. to form a Dirac fermion, is used to generate it and Bit terms through its ...

Elsevier2011