Skip to ContentSkip to Navigation
About usNews and EventsNews articles

Surface engineering: amorphous alloys and nanocrystallinity

13 June 2008

PhD ceremony: D.T.A. Matthews, 14.45 uur, Academiegebouw, Broerstraat 5, Groningen

Thesis: Surface engineering: amorphous alloys and nanocrystallinity

Promotor: prof. J.T. de Hosson

Faculty: Mathematics and Natural Sciences

 

This work encapsulates the production and properties of metallic amorphous and nanocrystalline alloys. Laser surface engineering has been proven to be a viable production method for developing thick amorphous coatings and their properties are shown to include high hardness, low friction and good wear resistance to both dry-sliding wear and, in the case of nanostructured coatings, abrasive wear.

Various mechanical tests have all been found to induce shear band formation, a characteristic feature of plastic deformation in amorphous alloys, and investigations have delved in to the further understanding of shear band formation in amorphous metallic alloys. Fundamental analysis of the volume of material involved in shear band formation and fracture of amorphous metallic alloys – the so-called liquid-like-layer – has been investigated by combined electron microscopy techniques to address some of the discrepancies in published data regarding this layer. A comparative study between the experimental value and theoretical value shows that theoretical analysis makes a gross overestimate of this layer since several assumptions do not hold true. Fracture does not take place instantaneously at the moment when the liquid like layer is at its maximum thickness and not all of the liquid like layer volume produces the characteristic veins associated with fracture of amorphous metallic alloys.

 

Last modified:15 September 2017 3.37 p.m.

More news

  • 23 April 2019

    From paperclip to patent

    How is it possible that an albatross doesn’t crash and die when it lands? And how come its large wings don’t break due to air resistance? That is what you would expect, according to the laws of aerodynamics. However, Professor Eize Stamhuis has discovered...

  • 17 April 2019

    Why lightning often strikes twice

    In contrast to popular belief, lightning often does strike twice, but the reason why a lightning channel is ‘reused’ has remained a mystery. Now, an international research team led by the University of Groningen has used the LOFAR radio telescope to...

  • 16 April 2019

    Still going strong after four decades

    On March 29th professor of Applied Physics Jeff de Hosson was offered a farewell symposium, a few months after his official retirement date near the close of 2018. ‘But 29 March was the 100th birthday of Jan Francken, my predecessor.’ Besides, De Hosson...