Study of Crack Initiation of 15-15Ti Austenitic Steel in Liquid PbBi

The austenitic steel 15-15Ti is being considered as one of the candidate materials for internal structural components of future heavy liquid metal (HLM) nuclear systems. This work studies the steel compatibility with liquid PbBi. Constant extension rate tensile (CERT) tests of tapered specimens were used to study sensitivity to liquid metal embrittlement (LME) and crack initiation. The taper creates a variation of stress along the gauge length which allows the identification of the stress and strain for the crack appearance. Testing was performed in air and in PbBi with 10(-6) to 10(-12) wt % oxygen content at 300 degrees C. Post-test observation by scanning electron microscopy (SEM) highlighted the crack morphology. An evaluation of the environmental effect on the crack initiation is presented.