Surface Crack Detection of Aluminum Alloy Using Injected Direct Current-Magnetic Field Measurement Method

Area of Science:

• Materials Science
• Non-destructive Testing
• Electromagnetism

Background:

• Aluminum alloys are critical in various industries.
• Detecting cracks is essential for structural integrity.
• Existing nondestructive techniques have limitations in sensitivity.

Purpose of the Study:

• To investigate the effectiveness of Injected Direct Current-Magnetic Field Measurement (IDC-MFM) for crack evaluation in aluminum alloys.
• To establish the correlation between magnetic field signals and crack dimensions (width and depth).
• To validate simulation findings with experimental data.

Main Methods:

• Utilized finite element simulation to model the magnetic field behavior around defects.
• Employed experimental testing on aluminum alloy specimens with artificial cracks.
• Used a high-sensitivity tunnel magnetoresistance probe for magnetic field detection.

Main Results:

• Magnetic field intensity at defects increases with applied current.
• Peak-to-peak tangential magnetic field (ΔB) strongly correlates with crack width and depth.
• Experimental results align with simulation predictions.
• ΔB shows a nonlinear positive correlation with crack width and a linear positive correlation with crack depth.

Conclusions:

• IDC-MFM demonstrates high sensitivity for crack size detection in aluminum alloys.
• The technique provides a feasible method for quantitative crack evaluation.
• IDC-MFM offers a promising nondestructive approach for ensuring the integrity of aluminum alloy structures.