Fabrication of Artificial Delamination Flaw Specimens and an Application of Active Thermography

Abstract

Combination of heterogeneous materials is an essential technique for performance improvement in many fields. But sometimes planer voids or delamination may exist at the interface between the coating and the base material or in the coating itself. In order to detect these voids, thermography measurement is a promising method because it has less material restrictions. We fabricated three types of measurement specimens which had different sizes and locations of pseudo-voids and attempted to detect the voids by active thermography with both large-area heating by a halogen lamp and localized heating with a fiber laser. In addition, we discuss the fabrication of the pseudo-void specimens using 3-D printing and the characterization of the sizes and the depths of the voids using active thermography. The difference between the peak temperature near the void and that in the non-void region indicates the potential for identification of the size or depth of the void.