나노압입시험을 이용한 벌크 비정질 합금의 상온 크립 거동 연구

Abstract

Unlike their crystalline counterparts, bulk metallic glasses (BMGs) have often exhibited time-dependent deformation (creep) at room temperature. A possible tool for analyzing this interesting behavior of BMGs (whose available sample size is still very limited) is instrumented indentation test. In this study, we attempted to systematically explore the room-temperature creep behavior of Cu-Zr binary BMGs via nanoindentation experiments. During nanoindentation creep test, the load was increased up to the peak load of 50 mN under various loading rate (0.1 to 2.5 mN/s) and then hold for 400s. Results are discussed in terms of the influences of free volume and loading rate on the time-dependent behavior and the viscoelastic (and possibly viscoplastic) properties of the BMGs.