3D mapping of dislocations-crack tip interaction in SrTiO3 with DFXM

Dislocations (line defects) in functional ceramics are generating rapid research interest for both functional and mechanical properties. Despite of recent years’ development for dislocation engineering into various oxides, a major challenge remains: crack initiation and propagation even in dislocation-rich regions can occur unexpectedly and lead to fracture of the samples. To overcome this challenge and better understand dislocation-crack tip interaction in oxides, here we propose to use SrTiO3 as a model system to use DFXM (dark-field X-ray microscopy) for imaging dislocations around cracks. DFXM will provide critical 3D information at micro/mesoscale with high resolution (~100 nm). Our preliminary DFXM test on SrTiO3 suggests this is a promising route. Samples with 4 different dislocation densities at pre-induced cracks will be probed. The spatial distribution of dislocations and their strain fields will be measured to feed our developed dislocation-based fracture mechanics model.