Thermoplastic deformation and micro/nano-replication of an Au-based bulk metallic glass in the supercooled liquid region

Abstract

In this paper, we reported the thermoplastic deformation and micro/nano forming ability of a Au49Ag5.5Pd2.3Cu26.9Si16.3 bulk metallic glass (BMG) in the supercooled liquid region (SCLR) at strain rates ranging from 1×10–4 to 3×10–2s−1. It is found that the deformation behavior of Au-based BMG has strong dependences on strain rate and temperature applied. The strain-rate sensitivity value, obtained by the strain-rate change method, approaches an unity (Newtonian flow) at low strain rates of 10–4s−1, but it decreases with increasing strain rate to ∼0.3 (non-Newtonian flow) at 10–2s−1. The homogeneous flow behavior is observed from the compressive test results. As the result of homogeneous flow, the deformability with a high compressive strain of ∼97% is achieved. The excellent micro/nano-patterning obtained at 430K is also demonstrated for imprinted stripes with a feature size of ∼156nm, signifying the good formability of this alloy in SCLR.