Low frequency wave propagation in multiphase polycrystalline materials

Area of Science:

• Materials Science
• Acoustics
• Solid Mechanics

Background:

• Wave propagation in heterogeneous materials is complex.
• Polycrystalline materials with multiple phases present unique challenges.
• Understanding effective properties is crucial for material design.

Purpose of the Study:

• To investigate wave propagation in multiphase polycrystalline materials.
• To derive explicit expressions for effective wavenumbers, attenuation, and phase speeds at low frequencies.
• To determine the influence of grain size distribution on wave attenuation.

Main Methods:

• Utilized a generalized Foldy approach with an independent scattering approximation.
• Assumed orthotropic grains with random orientations for isotropic effective properties.
• Derived explicit analytical expressions for low-frequency wave parameters.

Main Results:

• Obtained explicit expressions for effective wavenumbers, attenuation, and phase speeds.
• Demonstrated that the third moment of the grain radius distribution governs attenuation.
• Provided numerical examples for duplex materials based on phase volume concentration.

Conclusions:

• The generalized Foldy approach provides accurate low-frequency wave propagation predictions.
• Grain size distribution significantly impacts wave attenuation, specifically its third moment.
• The study offers a framework for analyzing wave behavior in complex multiphase materials.