Elastic-Viscoplasticity Modeling Of The Thermo-Mechanical Behaviour Of Chalcogenide Glass For Aspheric Lens Molding

Chalcogenide glass (ChG), as an alternative material in place of single-crystal germanium, is increasingly used in thermal imaging, night vision and infrared guidance systems owing to their excellent formability through precision glass moulding (PGM). The deformation mechanisms of these glasses at the molding temperature involve elasticity, plasticity, and viscous flow, which call for a new theoretical model to assist the design of PGM processes. This paper investigates the thermo-mechanical properties of Ge22Se58As20 at the temperature above its softening point and establishes a new elastic-viscoplasticity model to describe its thermo-mechanical behaviours.