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DAMREG Sintesi della relazione

Project ID: 320506
Finanziato nell'ambito di: FP7-IDEAS-ERC
Paese: France

Mid-Term Report Summary - DAMREG (Pushing the Frontier of Brittlness Damage Resistant Glasses)

The ERC program "DAMREG" is aimed at identifying new routes to reduce the brittleness of glass and at developing innovative glass-based materials offering a better damage resistance as well as multifunctional couplings. What we think the major achievements are as the project is reaching its mid-term is listed below:
- A unique mechanical testing machine, equipped with a piezoelectric actuator with a 5 nm displacement precision over a 2 cm displacement range, and with a load cell (1000 N) exhibiting a stiffness of 6.7 MN/m and a high sensitivity camera (1.2 e- read noise/25,000:1 dynamic), was completed. This apparatus is characterized by a very small compliance (i.e. the elastic energy stored in the machine upon testing is very limited) which is ideal to investigate crack extension and fracture in brittle materials.
- A transparent mechanoluminescent glass-particulate composite, emitting a chiefly green light under mechanical loading, was successfully synthesized and a constitutive law was proposed for the mechano-optical coupling which proved to result in a remarkable fit of the experimental data even for complex loading cycles. (Appl. Phys. Lett., 107, 151906 (2015))
- Transparent glasses were synthesized in the sodium- and barium-titanium-silicate system which exhibit a better resistance toward surface damage in comparison to standard soda-lime-silica glasses thanks to a suitable combination of mechanical properties (especially Young's modulus, Poisson's ratio, hardness and toughness). (J. Non-Cryst. Sol., 429, 129-142 (3015))
- A large batch (few cm long) of a transparent glass-ceramic with a composition close to the one of the fresnoite crystalline phase was obtained. This glass-ceramic shows improved mechanical properties and a great potential for mechano-electrical coupling.
- A surface damage map was proposed which allows for the prediction of the expected microcracking pattern (indentation crack type) and for the search for composition favoring the limitation of the residual stresses acting as a driving force for cracking. (Acta Mat., 61 5949-5965 (2013), Compte Rendus Mécanique of the Académie des Sciences, 342 46-51 (2014), and Phil. Trans. R. Soc. A, 373, 20140140 (2015))

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