Scania

Purpose and goal

The main goal of the project was to study fatigue cracks in industrially relevant cast irons during mechanical loading using synchrotron radiation microtomography. Since it is difficult to realize a fatigue loading cycle at a synchrotron facility a sub-goal was to develop a lab-based method for the introduction of fatigue cracks.

Expected results and effects

In total, 140 3D-images were obtained, during five days of granted academic beamtime, at the Swedish beamline P21 at DESY in Hamburg. The studied specimens all had internal fatigue cracks which were introduced using the aforementioned method. These cracks were imaged during mechanical loading to be able to study their behaviour in terms of opening/closing and propagation in relation to the microstructure. This data deepens the understanding for fatigue cracks for this group of materials.

Planned approach and implementation

The project followed the original test plan. Test specimens were manufactured from industrially relevant raw material supplied by Scania and then subjected to fatigue loading to introduce fatigue cracks without rupturing the specimens. The behaviour of these cracks was then studied during mechanical loading at a synchrotron radiation facility (P21, DESY). A streamlined workflow has been developed allowing for new ways to understand fatigue-induced cracks in relation to the microstructure.