Ceramic materials can deform like metals and polymersErkka J. Frankberg’s doctoral dissertation explores the plastic deformation of ceramics at room temperature. While ceramics are attractive for many applications due to their superior resistance to heat, corrosion and wear, their brittleness is limiting their more widespread utilization.
A coffee mug falls and shatters to pieces on the floor, spilling the dark substance on my light coloured fluffy carpet. This is the familiar nature of ceramic bulk materials, such as aluminium oxide (Al2O3): brittleness and fracture on impact. In engineering, ceramics have many outstanding properties compared to metals and polymers, such as resistance to extreme heat, diffusion, corrosion and wear. In addition, ceramic materials exhibit a range of functional properties such as dielectricity, semiconductivity, photocatalysis, superconductivity, piezoelectricity and bioactivity. The main obstacle for the wider utilization of the superior capabilities of ceramics in engineering is the brittleness of these ionic and/or covalently bonded materials.
“At room temperature, ceramic materials have a very limited capability of deforming plastically and because of that, improving the fracture resistance of ceramics has been one of the primary scientific goals in materials science for decades”, says Frankberg, who will be defending his doctoral thesis at TUT.
Relatively cheap and abundantly available engineering ceramics, such as aluminium oxide, with room temperature plasticity would be a breakthrough in the field of engineering and materials science. In his doctoral dissertation, Erkka J. Frankberg demonstrates through a combination of experiments and atomistic simulations that amorphous aluminium oxide can deform plastically at rates similar to metals or polymers even at room temperature.
The result can be seen as a breakthrough and additional funding is applied actively to study the phenomena more broadly.
“The first results are applied to improve safety of nuclear energy”, says Frankberg who is currently researching the subject at Italian Institute of Technology.
In addition, the results could be used to improve for example mechanical resistance of batteries and electronics.
Frankberg selected aluminium oxide (Al2O3) as the study material for several reasons.
“First, it is normally extremely brittle in all common forms, and secondly it is a fundamentally important engineering material for the world: Oxygen (O) and Aluminium (Al) are the first and third most abundant elements in the Earth’s crust, making AlO derivatives extremely abundant.”
Public defence of a doctoral dissertation on Friday, 2 March
MSc (Tech) Erkka J. Frankberg’s doctoral dissertation in the field of materials science entitled ‘Plastic deformation of Amorphous Aluminium Oxide – Flow of inorganic glass at room temperature’ will be publicly examined at the Faculty of Engineering Sciences of Tampere University of Technology (TUT) in room K1702 in the Konetalo building (address: Korkeakoulunkatu 6, Tampere, Finland) at 12 noon on Friday, 2 March 2018.
The opponents will be Professors Jérôme Chevalier (Insititut National des Sciences Appliquées de Lyon, France) and Roman Nowak (Aalto University, Finland). Professor Erkki Levänen from the Laboratory of Materials Science at TUT will act as Chairman.
Erkka J. Frankberg (30) comes from Urjala, Finland, and works as researcher at the Italian Institute of Technology, Milan.
The dissertation is available online at: http://urn.fi/URN:ISBN:978-952-15-4108-7