Mechanical properties of CaO-MgO-Al2O3-SiO2 glass-ceramics

Abstract

During the candidate's masters studies, new opaque and colored-transparent glass-ceramics of the MgO-Al2O3-SiO2 system were developed. At that time, only the hardness and indentation fracture toughness were measured by Vickers hardness test. Following these results, for his PhD project, two main objectives were proposed: the first is to reformulate the studied glasses to obtain colorless-transparent glass-ceramics. The second objective is to correlate changes in the mechanical properties with the nano or microstructure. The parent glass reformulation and synthesis as well as sample heat treatments will be carried out at the Vitreous Materials Laboratory (LaMaV) of the Federal University of São Carlos. The mechanical properties to be investigated, elastic moduli, toughness and hardness of the glass-ceramics produced by different heat-treatments, which lead to different microstructures, will take place at the Laboratory of Applied Mechanics (LARMAUR) of the University of Rennes 1. There, the elastic moduli will be measured, at room temperature, using the ultra-sound echography technique and at high temperatures, by mechanic resonance of plaques and disks. Toughness will be measured by the chevron-notch fracture test, and hardness will be determined by using Vickers test. It is also proposed to measure the glass viscosity via indentation, coupled to the measurement of elastic modulus at different temperatures. At the end, the work is expected to contribute to the knowledge of the crystallization mechanisms, to elucidate the phase nucleation order, and the contribution to each phase to the mechanical properties of the resulting glass-ceramics. (AU)