Journal of Materials Science, Vol.29, No.15, 4022-4026, 1994
Interfacial Fracture-Toughness Measurement Using Indentation
Recent models have been developed for relating fracture toughness to indentation strengths for brittle monolithic materials. Thus, indentation may provide a simple and non-destructive means to measure fracture toughness. The indentation technique is further explored to evaluate the interfacial toughness in this work. When microindentations at loads ranging from 50 g to 4 kg were placed close to the interface of an aluminium/aluminum composite laminate, the interface stayed intact. In contrast, the interface of a niobium silicide/niobium laminate indented under similar conditions was found to debond, indicating a weaker interface. However, a Rockwell indenter at loads ranging from 60 to 150 kg were sufficient to debond the interfaces of two of the aluminum composite/aluminum laminates. Finally, the interfacial toughness is correlated to the indenter load and the delamination length along the interface. A power-law relationship was found between the load and the delamination length.