Technical Support

1. Morphological Image Features

Sheet-like Low-Reflection Region

In ultrasonic C-scan images, delamination defects usually appear as patchy or strip-shaped dark areas. Obvious contrast is formed by the acoustic impedance difference with surrounding normal regions.

The defect boundary is clear, and multiple connected regions may appear at different interfacial layers, presenting continuous low-reflection signal bands.

Phase Reversal Feature

A delamination interface (e.g., resin–air gap) causes a 180° phase reversal of the reflected wave. In color-coded images of scanning acoustic microscopes, delamination areas are prominently marked in red or bright colors.

2. Signal Response Characteristics

Attenuation or Disappearance of Backwall Echo

Delamination significantly absorbs and scatters ultrasonic energy, reducing or even completely eliminating backwall echoes, especially for large-area delaminations.

Correlation Between Defect Echo and Backwall Echo

When improving detection sensitivity, the amplitude of defect echoes in delaminated regions usually decays slower than the backwall echo, forming a distinct dynamic response difference.

3. Spatial Distribution Characteristics

Positional Relevance

Delaminations mostly occur at material bonding interfaces (such as interlayers of composite laminates) or process weak zones (e.g., riser ends of castings).

Delamination tends to extend inside the material, forming continuous abnormal signal bands parallel to the material surface.

Tomographic Scanning Performance

With multi-layer tomographic scanning (up to 50 layers) of the scanning acoustic microscope, the extension range of delamination at different depth sections can be observed, reconstructing the three-dimensional morphology of defects.

4. Technical Quantitative Parameters

Defect Area Ratio

The system automatically calculates the proportion of delaminated areas through phase analysis and image processing algorithms, outputting quantified percentage values (e.g., a defect ratio ≥5% indicates severe delamination).

Resolution and Boundary Accuracy

High-frequency probes (above 50 MHz) achieve micron-level resolution, clearly displaying burr-like or zigzag details at delamination edges, which helps determine the root cause, such as mechanical peeling or thermal stress cracking.

Summary

Delamination defects shall be comprehensively judged by combining morphology, signal response, spatial distribution and quantitative parameters. High-contrast phase reversal and backwall echo attenuation are the core identification features of delamination.