Imaging textural variation in the acoustoelastic coefficient of aluminum using surface acoustic waves

R. Ellwood, T. Stratoudaki, S. D. Sharples, M. Clark, M. G. Somekh

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Much interest has arisen in nonlinear acoustic techniques because of their reported sensitivity to variations in residual stress, fatigue life, and creep damage when compared to traditional linear ultrasonic techniques. However, there is also evidence that the nonlinear acoustic properties are also sensitive to material microstructure. As many industrially relevant materials have a polycrystalline structure, this could potentially complicate the monitoring of material processes when using nonlinear acoustics. Variations in the nonlinear acoustoelastic coefficient on the same length scale as the microstructure of a polycrystalline sample of aluminum are investigated in this paper. This is achieved by the development of a measurement protocol that allows imaging of the acoustoelastic response of a material across a samples surface at the same time as imaging the microstructure. The development, validation, and limitations of this technique are discussed. The nonlinear acoustic response is found to vary spatially by a large factor (>20) between different grains. A relationship is observed when the spatial variation of the acoustoelastic coefficient is compared to the variation in material microstructure.

Original languageEnglish
Pages (from-to)2811-2819
Number of pages9
JournalJournal of the Acoustical Society of America
Volume138
Issue number5
DOIs
Publication statusPublished - 30 Nov 2015
Externally publishedYes

Keywords

  • nonlinear acoustic techniques
  • polycrystalline structure
  • acoustoelastic coefficient
  • microstructure
  • aluminum
  • acoustoelastic response
  • imaging

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