Detail publikace

Cracks detection in Mg alloy by electro-ultrasonic spectroscopy

TOFEL, P. ŠIKULA, J. HÁJEK, K. TROJANOVÁ, Z. BUMBÁLEK, L.

Originální název

Cracks detection in Mg alloy by electro-ultrasonic spectroscopy

Typ

článek v časopise - ostatní, Jost

Jazyk

angličtina

Originální abstrakt

New non-destructive testing (NDT) method is based on the effect of the ultrasonic vibrations on the electron transport in samples with macroscopic defects as cracks or defect centers affecting electrical conductivity. On the frequency given by the subtraction of exciting frequencies new intermodulation signal appears. Its value is given by electric resistance modulation by the defects and un-homogeneities in the sample structure. In our experiment we used the ultrasonic actuator with frequency fU when the period of wave is longer than the dielectric relaxation time in analyzed sample. In this case the effects of electron bunching by ultrasonic wave are negligible. The ultrasonic wave length is much larger than the electrons mean free path and the wave period is much longer than the mean free time among the electrons collision with scattering centers and defects. Then the electron transport is described by the quasi-steady state transport equation in one-electron approximation. Because of the requirement of charge neutrality, no net AC electric current with the ultrasonic wave frequency fU can be carried by the wave. Similar situation exists for samples excited by standing ultrasonic waves. The electrical conductivity varies with time due to that the cracks geometry is changed with frequency of the ultrasonic vibration. The sample conductivity is affected mainly by the presence of cracks and defects boundaries perpendicular to the electric current density vector. In our experiment the amplitude of ultrasonic vibration is so low that no new cracks are generated and then the proposed testing method belongs to NDT.

Klíčová slova

NDT, spectroscopy, resistance change, crack geometry change

Autoři

TOFEL, P.; ŠIKULA, J.; HÁJEK, K.; TROJANOVÁ, Z.; BUMBÁLEK, L.

Rok RIV

2011

Vydáno

18. 1. 2011

Nakladatel

Trans Tech Publications

Místo

Switzerland

ISSN

1013-9826

Periodikum

Key Engineering Materials (print)

Ročník

465

Číslo

1

Stát

Švýcarská konfederace

Strany od

350

Strany do

353

Strany počet

4

BibTex

@article{BUT50237,
  author="Pavel {Tofel} and Josef {Šikula} and Karel {Hájek} and Zuzanka {Trojanová} and Leoš {Bumbálek}",
  title="Cracks detection in Mg alloy by electro-ultrasonic spectroscopy",
  journal="Key Engineering Materials (print)",
  year="2011",
  volume="465",
  number="1",
  pages="350--353",
  issn="1013-9826"
}