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

In this paper, we reported the thermoplastic deformation and micro/nano forming ability of a Au₄₉Ag_5.5Pd_2.3Cu_26.9Si_16.3 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.