Mechanical behavior of bulk metallic glass prepared by copper mold casting with reversed pressure

The effect of applied reversed pressure on mechanical properties of bulk metallic glass (BMG) prepared by copper mold casting was investigated by quasi-static compression experiment and Weibull statistics. The BMG samples prepared by negative pressure casting exhibit higher strength and larger plasticity compared with those prepared by positive pressure casting. The applied reversed pressure plays a key role not only in the formation of cast defect at macro-scale but also for the distribution of free volume at micro-scale, which is responsible for the variable values of strength and plasticity, respectively. In copper mold casting process, negative pressure is also beneficial for reducing porosity content and homogeneous distribution of free volume, which in turn leads to the improvement of the reliability of BMGs. (C) 2016 Elsevier B.V. All rights reserved.