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Ansprechpartner

Dr.-Ing. Mario Walter

mario walter does-not-exist.kit edu

Telefon +49 721 608 23753

Beteiligte Mitarbeiter

Ralf Dahm

Investigations to the influence of strain gradients on the mechanical behaviour of metallic materials in small dimensions

Due to the development of materials structures and processes at micro and nano length-scales there is an increasing need to characterize materials in these dimensions in terms of deformation and fracture.

It is known that within small-scale dimensions the occurrence of strain gradients plays a crucial role, in particular for the deformation of metallic materials.

An efficient method to generate well defined multiaxial stress-strain fields are torsion experiments. Performed on thin wires with comparable microstructure and different diameters they allow non-restrictive studies of the influence of strain gradients on the mechanical behaviour of materials.

Within the scope of this project the mechanical behaviour of different metallic materials such as gold, copper, and aluminium under uniaxial and multiaxial load conditions will be investigated. For the experiments currently performed at room temperature (RT) a specifically developed test facility will be used.

Mikrotorsion Mikrotorsion2
measuring principle:
Ml = Mr = 0.5 Mt = 0.5 (F • a)
 

Experimental setup for tensile and/or torsion tests on thin wires
Experimental setup

 

The facility generally allows to perform:

  • monotonic and cyclic tensile tests
  • monotonic and cyclic torsion tests
  • combined tensile-torsion tests

on specimens with a diameter between 5 and 100 µm. High sensitivity actuators and sensors guarantee accurate measurements of individual parameters with highest resolutions.

 
 influence of strain rates on the deformation behaviour of gold wires under torsional load
Results from investigations on the influence of strain rates
on the deformation behaviour of gold wires under torsional load

 

 

Current sub-project(s):

Investigations to the hardening behaviour of small structures under loadings where strain gradients occur