Non-Destructive Micro Crack Detection in Modern Materials

摘要

For the purpose of nondestructive crack detection X-ray refraction is applied. Micro cracks are essential indicators for fatigue and degradation. The physics of refractive crack detection is based on the scattering of x-rays at the phase boundaries of different materials or gaps. The sensitivity for cracks is nearly independent of the crack width and it is independent from the spatial (scanning) resolution of the system, because the integral scattering intensity is a measure of the total crack density in a certain material. Due to topographic measurements (i.e. two-directional scanning of the sample) and high resolution x-ray refraction tomography, the spatial distribution of cracks is also detectable. In addition, the measurement of crack orientation can be performed with high accuracy. Even the correlation between crack density and mechanical parameters is possible. Mainly materials of low absorption like polymers, ceramics or composites are investigated.