Modeling and experimental determination of physical properties of Gex-Gay-Se1-x-y chalcogenide glasses I: Structure and mechanical properties

Abstract A series of ten Ge x Ga y Se 1-x-y glasses within the topological constraint regime of r > = 2.3 to 2.8 were processed for physical property testing to compare measured to calculated property values enabling further understanding of structure-related mechanical property evolution. Average bond energies were calculated for each glass to elucidate structure and property relationships. Raman analysis was performed to correlate the topological constraint theory to experimentally determined structural units. Young's modulus and Vickers hardness, respectively, were shown to increase with increasing coordination number from 14.42 GPa and 911 MPa at r > = 2.4 to 29.44 GPa and 2295 MPa at r > = 2.8. Poisson’s ratio decreased linearly with increasing coordination number from 0.2996 at r > = 2.4 for Ge 0.15 Ga 0.05 Se 0.85 to 0.2477 at r > = 2.8 for Ge 0.25 Ga 0.15 Se 0.60 . These properties indicate a strong dependence on the topological network of the glass, in which continued crosslinking and interconnectivity lead to a direct increase or decrease of the respective mechanical property. It was found that theoretical values were in good agreement with measured experiment values, elucidating the impact of the energy required to propagate a crack tip or alter bond lengths and atom positions.