Forensic in situ investigations, for example for aviation, maritime, road, or rail accidents would benefit from a method
that may allow to distinguish ductile from brittle fractures of metals - as material defects are one of the potential causes
of such accidents. Currently, the gold standard in material studies is represented by scanning electron microscopy
(SEM). However, SEM are large, lab-based systems, therefore in situ measurements are excluded. In addition, they are
expensive and time-consuming. We have approached this problem and propose the use of Optical Coherence
Tomography (OCT) in such investigations in order to overcome these disadvantages of SEM. In this respect, we
demonstrate the capability to perform such fracture analysis by obtaining the topography of metallic surfaces using OCT.
Different materials have been analyzed; in this presentation a sample of low soft carbon steel with the chemical
composition of C 0.2%, Mn 1.15%, S 0.04%, P 0.05 % and Fe for the rest has been considered. An in-house developed
Swept Source (SS) OCT system has been used, and height profiles have been generated for the sample surface. This
profile allowed for concluding that the carbon steel sample was subjected to a ductile fracture. A validation of the OCT
images obtained with a 10 microns resolution has been made with SEM images obtained with a 4 nm resolution.
Although the OCT resolution is much lower than the one of SEM, we thus demonstrate that it is sufficient in order to
obtain clear images of the grains of the metallic materials and thus to distinguish between ductile and brittle fractures.
This study analysis opens avenues for a range of applications, including: (i) to determine the causes that have generated
pipe ruptures, or structural failures of metallic bridges and buildings, as well as damages of machinery parts; (ii) to
optimize the design of various machinery; (iii) to obtain data regarding the structure of metallic alloys); (iv) to improve
the manufacturing technologies of metallic parts.