Temperature-induced anomalous brittle-to-ductile transition of bulk metallic glasses

We report an anomalous brittle-to-ductile transition (BTDT) in Au-based bulk metallic glasses (BMGs). Despite of brittle failure without noticeable plastic strain under uniaxial compression at room temperature, the Au-based BMGs exhibit remarkable plasticity at cryogenic temperatures, which is opposite to the BTDT in crystalline materials. This anomalous transition originates from the strong temperature dependence of the fundamental deformation units, viz. shear transformation zones, giving rise to both superior plasticity and high strength of BMGs for low-temperature applications. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3669508]