Non-destructive evaluation of thermal diffusivity distributions of functionally graded materials by photothermal radiometry

Y. Nagasaka, T. Sato, T. Ushiku

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

We have developed a new apparatus to evaluate thermal duffusivity and thermal effusivity distributions of functionally graded materials (FGMs) by photothermal radiometry (PTR). Since this method is applicable to the low modulation frequency range down to 1 mHz, it is suitable for the measurement of thermally thick samples such as FGMs. We have solved heat conduction equations for a multi-layered model applicable to the present PTR measurement. The effects on the phase lag measurement caused by three-dimensional heat in the low frequency range have also been analysed. For solving the inverse problem of extracting thermophysical properties from phase lag versus frequency data, we have proposed an analytical method in which the distribution of thermal diffusivity is approximated by an exponential function. The distributions of thermal diffusivity and thermal effusivity have been determined for a four-layered Ni/ZrO2 FGM at room temperature.

Original languageEnglish
Pages (from-to)2081-2088
Number of pages8
JournalMeasurement Science and Technology
Volume12
Issue number12
DOIs
Publication statusPublished - 2001 Dec

Keywords

  • Functionally graded materials
  • Multi-layered three-dimensional model
  • Non-destructive evaluation
  • Photothermal radiometry
  • Thermal depth profile
  • Thermal diffusivity

ASJC Scopus subject areas

  • Instrumentation
  • Engineering (miscellaneous)
  • Applied Mathematics

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