Inversion methodology for ultrasonic characterization of polycrystals with clusters of preferentially oriented grains

Area of Science:

• Materials Science
• Mechanical Engineering
• Non-destructive Testing

Background:

• Titanium alloys are critical in aerospace but susceptible to cold dwell fatigue due to microtexture.
• Microtexture, characterized by crystallite orientation, significantly impacts component lifespan.
• Nondestructive characterization of microtexture is essential for reliable performance assessment.

Purpose of the Study:

• To develop an inverse ultrasonic methodology for quantifying microtexture region (MTR) parameters.
• To overcome the limitation of requiring prior knowledge of elastic constants for ultrasonic inversion.
• To enable nondestructive microtexture characterization for aerospace applications.

Main Methods:

• Utilized far field attenuation and backscattering models for ultrasonic wave interaction with microtexture.
• Employed directional ultrasonic measurements (backscattering, attenuation, velocity) for data acquisition.
• Developed an inversion technique requiring no prior information on material microstructure or phase elastic properties.

Main Results:

• Successfully quantified mean Microtexture Region (MTR) sizes, morphology, and elastic scattering factors.
• Demonstrated the inversion methodology through simulations.
• Achieved good agreement between ultrasonic inversion results and destructive Electron Backscatter Diffraction (EBSD) analysis.

Conclusions:

• The proposed inverse ultrasonic methodology provides a viable, nondestructive approach for microtexture characterization.
• This method eliminates the need for prior knowledge of elastic constants, making it applicable to engineering alloys.
• Accurate MTR parameter quantification supports improved fatigue life prediction and material design in aerospace.