Unprecedented ultra high-speed recording to track explosions and crack propagation

Fuses are used as essential safety devices in electronics to overcome short circuits, overloading or device failure,  allowing to remove power from faulty systems.  operation of fuses  involves phenomena that are still not fully understood in the scientific community, as fuse breakdown typically takes place on timescales much less than a millisecond inside an opaque medium.  These phenomena take place when material is ejected because of the release of high energy densities transformed rapidly into heat and kinetic energy. Fuses employ a ceramic case which is opaque to visible light, so hard X-ray imaging is necessary to visualize the melting and vaporization of the metal fuse strip during electric arc ignition. 

A team of scientists from the ESRF, together with the international fuse company Mersen, has managed to record exactly what happens in the fuse as it explodes using the new technique. They recorded a time series of X-ray radiographs during electric arc ignition of the fuse operation. The images reveal the melting of the silver metal strip and the appearance of plasma around the metal strip due to its partial vaporization at high temperature. “This results show how important what happens in a microsecond is. Before this experiment we could only do post-mortem observations, so we are very excited about these new possibilities”, explains Jean-Louis Gelet, R&D Senior-Engineer from Mersen.

The research possibilities of this new development are many: “We can now study systems like extreme loading of materials leading to failure and many fast processes in advanced manufacturing which we couldn’t study before. This technique advances the use of  fastest and most performing camera you can find now in the world to seeing the invisible using X-rays” , explains Margie Olbinado, post-doctoral researcher at the ESRF and author of the paper where the new technique is described.

“This technique just arrives in time for the EBS project of the ESRF. With the new storage ring, more dense objects can be studied at higher spatial resolution: unique opportunities for beamline ID19. This means that failure if more complex devices are accessible, but also crack propagation driven by explosives: an important aspect for the mining industry.” 

The fuse as it explodes. Credits: M. Olbinado.

References:

Olbinado, M. et al, Optics Express, Vol. 25, Issue 12, pp. 13857-13871 (2017).

Gelet J-L et al, Proc. of COSYS-DC 2017 - International Conference on Components and SYStems for DC Grid, March 2017, Grenoble, France
Gelet J-L et al, 13eme edition du Colloque sur les Arcs Electriques (CAE XIII) - 3eme Workshop Arcs et Contacts Electriques (ACE 2017).

 

Top image: The fuse as it breaks. Credits: M. Olbinado