Author(s)

M. Goken, H. Vehoff & P. Neumann

Abstract

The scanning probe microscopy has great advantages over other high- resolutional techniques like transmission electron microscopy in that no exten- sive specimen preparation, such as thinning, is required. This is important for examinations of crack tips, since thin film effects obscure the deformation be- havior of cracks. For the first time, the concurrent processes of crack tip blunt- ing by dislocation emission and unstable crack propagation were studied sys- tematically with the atomic force microscope (AFM). Brittle cracks were initi- ated in NiAl single crystals. NiAl serves as a model alloy for the mechanical behavior of intermetallic compounds. A small bending device was constructed in which the specimens were loaded stepwise

Keywords