A Study on Viscous Flow of the Zr-based Bulk Metallic Glass in an Undercooled Liquid State

Zr계 벌크 비정질 합금의 과냉 액상 영역에서의 점성 유동 현상 연구

In this present study, mechanical properties of the Zr-Ti-Cu-Ni-Be bulk metallic glass are characterized by compression test over a wide range of temperatures and strain rates. Three different types of deformation behavior have been identified as a result, viz., Newtonian viscous flow, non-Newtonian flow and brittle fracture without plastic deformation. A transition state theory is applicable fur the flow stress - strain rate curve that contains the transition from Newtonian to non-Newtonian flow. Based on the relationship between viscosity and strain rate within undercooled liquid state, we can easily obtain the experimental deformation map and suggest the boundaries among different deformation behavior of this alloy.