FRACOGLACE

Controlled crystallization in glass leads to meso-structured materials denominated glass-ceramics (GC), which consist of nano/microcrystals dispersed in a residual glass. GC take advantage of beneficial ceramic and glass properties and have numerous applications, e.g., medical implants, cell phone displays. However, the susceptibility of GC to stress corrosion cracking (SCC) has been scarcely studied. This phenomenon is highly dependent on the relative humidity and temperature, and on material parameters (chemical composition and microstructure) and can severely restrict GC´s uses due to crack propagation and fracture under (apparently) harmless stresses. The project’s objective is to understand the link between the GC structure and fracture properties (SCC to dynamic fracture) by bringing together experts from different fields. Groups concern UFSCar in Brazil (experts in GC development, fabrication and characterization and computer simulation), IPR Rennes University (experts in sample shaping, mechanical testing, molecular and multiscale simulation), and CEA-Saclay (experts in SCC, fracture and statistical analysis). The project includes three principal axes: 1/ Sample fabrication and nanostructural and rheological characterization: Techniques includes AFM, Raman, SEM. 2/ Fracture behaviour: This work will establish the full SCC curve in controlled environment from the static fatigue limit to the fracture toughness. Additional statistical tools (stochastic modelling, fractal analysis) aid in analysing fracture surfaces. Experimental data will be supplemented by simulations at different scales, providing insights on the mechanically induced nanostructural changes. 3/ The dataset obtained in axes 1 and 2 will be used to rationalize the relationships between structure, and mechanical, fracture and SCC properties of GC. This collaboration will include frequent exchanges between both countries and the involved students will greatly benefit from the different expertise.