Inhomogeneous to homogeneous transition in an Au-based metallic glass and its deformation maps

Transition from inhomogeneous to homogeneous deformation was characterized in an Au49Ag5.5Pd2.3Cu26.9Si16.3 metallic glass by compression of micro-scaled pillar samples and morphological observations of deformed specimens. In compression, the transition was revealed as the absence of flow serration in a stress–strain curve. Morphologically, it corresponds to the disappearance of localized shear band and the sample is uniformly deformed. The transition was found to be both temperature and strain rate dependent, and at a higher strain rate, it occurred at a higher temperature. The homogeneous deformation and, in particular the stress overshoot phenomenon, could be described by a shear transition zone model. Based on the current data, deformation maps were developed for the Au49Ag5.5Pd2.3Cu26.9Si16.3 metallic glass.