Determination of the creep crack initiation properties using pre-cracked small punch tests

The use of pre-cracked small punch creep test specimens (p-SPCT) is analyzed in this paper as an alternative method to obtain the Creep Crack Initiation (CCI) time in those cases where there is not enough material to use CT specimens. The material selected was an AZ31B magnesium alloy. The geometry of the specimens used was 10 × 10 mm square with a thickness of 0.5 mm. An initial crack-like notch was created in the SPT specimens by means of a laser micro-cutting technique. Conventional compact specimens (CT-20) were tested at T = 150 °C as a reference for CCI determination. The definition of an equivalent load for p-SPCT was seen to be a good methodology, and a λ parameter was defined to convert the p-SPCT to an equivalent C(T) load that produces the same CCI time. The influence of temperature and material on the λ parameter still remains to be investigated.