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Modeling of ultrasonic nonlinearities for dislocation evolution in plastically deformed materials: Simulation and
Wujun Zhu1, Mingxi Deng2, Yanxun Xiang1
1Key Laboratory of Pressure Systems and Safety of MOE, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China.
Ultrasonics
|March 8, 2016
Summary
This study links ultrasonic wave nonlinearity to plastic deformation in martensite stainless steel. Increased plastic strain enhances acoustic nonlinearity, driven by evolving dislocation structures.
Area of Science:
- Materials Science
- Solid Mechanics
- Acoustics
Background:
- Understanding nonlinear ultrasonic wave propagation is crucial for assessing material damage.
- Plastic deformation significantly alters material properties, impacting wave behavior.
- Dislocation evolution is a key factor in material nonlinearity.
Purpose of the Study:
- To establish a nonlinear constitutive relationship for ultrasonic wave propagation in plastically damaged media.
- To investigate the influence of mixed dislocation evolution on acoustic nonlinearity.
- To validate simulation results with experimental data.
Main Methods:
- Developed a nonlinear constitutive model incorporating mixed dislocation evolution.
- Performed finite element simulations of longitudinal ultrasonic wave propagation.
- Conducted experimental measurements on plastically deformed martensite stainless steel (30Cr2Ni4MoV).
Main Results:
- Simulated and experimental results demonstrated a monotonic increase in the normalized acoustic nonlinearity parameter with plastic strain.
- Acoustic nonlinearity was found to correlate directly with plastic strain.
- Microscopic analysis confirmed dislocation density, length, type, and fraction as primary drivers of acoustic nonlinearity.
Conclusions:
- The proposed nonlinear constitutive relationship accurately predicts ultrasonic wave behavior in plastically deformed materials.
- Dislocation evolution is the primary mechanism responsible for acoustic nonlinearity changes during plastic loading.
- This research provides a foundation for using nonlinear ultrasonics to characterize plastic damage in metals.
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