Nonlinear dynamic instability in brittle fracture of GaAs

Abstract

The process of brittle fracture in gallium arsenide was investigated to clarify the relation between the dynamics of crack propagation and the observed structure on the fracture surface with time-sensitive and structure-sensitive methods. Within the full range of length scales, i.e., spanning eight orders of magnitude from angstrom units to centimeters, the fracture surface was characterized with a manifold of structure-sensitive methods comprising optical microscopy, profilometry, atomic force microscopy, and scanning tunneling microscopy. We found that it is possible to predict the local atomic-scale microstructure of a fracture surface from the knowledge of the global macrostructure. The investigation of the fracture kinetics showed that the crack propagation process is characterized by three distinct velocity ranges. The present experimental results on structure and kinetics are consistently interpreted within the framework of a nonlinear dynamic instability in crack propagation.