The tendency to reduce specimen size for fracture toughness characterization of structural materials is gaining a spectacular interest in particular for irradiated materials. Indeed, the miniaturized compact tension (mini-CT) with a size of 10×10×4.2 mm is becoming very popular. With such a small volume, a large number of mini-CT specimens can be extracted from broken Charpy impact specimens and therefore makes this geometry very attractive and consequently several round robin exercises are organized to qualify this geometry. SCK•CEN has gained a lot of experience since the first usage of this geometry more than a decade ago. This geometry was qualified and tested in both unirradiated as well as irradiated condition.
This paper overviews the SCK•CEN experience using the mini-CT geometry for fracture toughness characterization. In particular, it discusses the reliability of this geometry in comparison to large specimens such as the precracked Charpy and compares the advantages and limitations of such a geometry to derive some recommendations.