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Mechanical Spectrometer (Internal Friction Machine)

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Internal_friction_machine.JPG

Contact details

Risanti, Doty Dr
Aerospace Engineering (LR), Fundamentals of Advanced Materials
Kluyverweg 1, 2629 HS Delft
Tel : +31 (0)15 27 88621
E-mail : d.d.risanti@tudelft.nl
Website : Open website

General Information

Instrument:

Mechanical Spectrometer (Internal Friction Machine)

Location:

Reactor Institute Delft

Key words:

Spectroscopy, characterization, internal friction/damping, mechanical testing, defects in solids.

Measured quantity:

The internal friction is a measure of the mechanical energy dissipated by a solid when subjected to an external mechanical oscillating stress.

Main application:

This energy absorbed is directly related to the number and kind of mobile defects present inside the solid, so information about the microstructure of the material can be obtained in a non-destructive way.

Instrument specification

Mechanical spectroscopy, also known as internal friction, is a spectroscopic technique in which a mechanical oscillating stress (applied by torsioning) at a certain frequency is applied on a solid. The stress applied has to be below the elastic limit of the material. Under this condition, the deformation will be recovered upon release of the applied stress. Deformation is composed of two contributions; the elastic (linearly proportional to the applied stress with an instantaneous response) and an anelastic contribution (much lower in magnitude and showing delayed response, which is due to dissipative, i.e. frictional, losses in the material). The anelastic response is related to the motion of defects (dislocations, interstitials, vacancies… etc.) and results in dissipation of energy. The internal friction is a measure of the mechanical energy dissipated and depends on the frequency and temperature applied during the experiment. This energy absorbed is directly related to the number and kind of mobile defects present inside the solid, as well as to the characteristic motion that they undergo. Therefore, the measurement of internal friction can be used to obtain information about the microstructure of the material in a non-destructive way.

 

  • Temperature range: 100 - 1200 K

     

  • Strain amplitude range: 10-4 - 10-6

     

  • Frequency range: 0.1 – 10 Hz

     

  • Sample dimensions: (L x W x T) 58 x 4 x 1 mm3