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 Au ₄₉Ag _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.