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Updated: Aug 1, 2026
09:35
Applying Dynamic Strain on Thin Oxide Films Immobilized on a Pseudoelastic Nickel-Titanium Alloy
Published on: July 28, 2020
Wave propagation in an anisotropic nickel-based superalloy
1Department of Physics, University of the Witwatersrand, Johannesburg, South Africa. amulele@physnet.phys.wits.ac.za
Ultrasonics
|June 1, 2000
Summary
Elastic anisotropy significantly affects ultrasound wave behavior in nickel-based single crystals. This study quantizes these effects, aiding non-destructive testing of critical components.
Area of Science:
- Materials Science
- Acoustics
- Solid Mechanics
Background:
- Elastic anisotropy in single crystals leads to complex ultrasound wave propagation phenomena.
- Understanding these effects is crucial for accurate non-destructive evaluation (NDE) of advanced materials.
- Nickel-based single crystals are vital in high-temperature applications like gas turbine blades.
Purpose of the Study:
- To investigate the impact of elastic anisotropy on ultrasound propagation characteristics.
- To analyze direction-dependent wave speeds, beam steering, and mode conversion.
- To validate experimental measurements against theoretical predictions for NDE applications.
Main Methods:
- Utilized a 25 MHz focused ultrasound probe in a water immersion setup.
- Studied ultrasound propagation in a nickel-based single crystal component.
- Employed the stationary phase approximation to predict echo amplitude behavior.
Main Results:
- Observed direction-dependent acoustic wave speeds and significant beam steering.
- Identified specific crystallographic directions with strong transverse mode echoes due to zero Gaussian curvature of the slowness surface.
- Noted the vanishing of transverse mode echoes in other directions due to symmetry.
- Measured considerable variations in longitudinal mode echo amplitude with direction.
Conclusions:
- Experimental results show good agreement with theoretical calculations for echo arrival times and amplitudes.
- Elastic anisotropy profoundly influences ultrasound behavior in single crystals.
- The findings support the application of this ultrasound technique for inspecting gas turbine blades.
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