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Spatial evolution of broadband Rayleigh waves indicative of material state
Seyed Hamidreza Afzalimir1, Maryam Ghodousi1, Cliff J Lissenden1
1Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, 16802, PA, USA.
Ultrasonics
|April 1, 2025
Summary
Laser ultrasound monitors metal additive manufacturing by analyzing V-shaped waveforms. This technique sensitively detects microstructural changes from thermal aging in Inconel718, offering insights into material properties.
Area of Science:
- Materials Science
- Non-Destructive Evaluation
- Acoustics
Background:
- Laser ultrasound is suitable for monitoring metal additive manufacturing.
- Material nonlinearity affects Rayleigh waveforms, impacting nondestructive evaluation.
- Assessing microstructure is crucial for material performance.
Purpose of the Study:
- To characterize the spatial evolution of pulse laser-generated V-shaped waveforms.
- To investigate the sensitivity of waveform steepness to microstructural changes in Inconel718.
- To evaluate laser ultrasound as a tool for assessing thermally aged materials.
Main Methods:
- Generated broadband V-shaped waveforms using a pulse laser.
- Characterized waveform spatial evolution using a steepness parameter.
- Documented microstructural changes (precipitates) via X-ray diffraction.
- Compared waveform steepness in thermally aged and unaged Inconel718 samples.
Main Results:
- Thermal aging of Inconel718 caused precipitation of multiple phases (γ', γ'').
- These precipitates increased material nonlinearity.
- Waveform steepness showed significant sensitivity to the material state after thermal aging.
Conclusions:
- Laser-generated ultrasound can effectively monitor microstructural evolution in metal additive manufacturing.
- The steepness parameter of V-shaped waveforms is a sensitive indicator of material nonlinearity and microstructure.
- This technique offers potential for unique insights into material microstructure and mechanical properties.
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