Direct observation of fracture in brittle materials in the SEM using a double torsion testing technique

Abstract

AbstractThis paper describes an in‐situ testing technique for obtaining greater understanding of fracture mechanisms in brittle materials through direct observation of controlled fracture. The technique utilises constant stress intensity double torsion (DT) specimens loaded inside the specimen chamber of a conventional scanning electron microscope. With this method the control of discrete crack advance is extremely good, comparable with the limit of resolution. Evidence of the DT in‐situ method's fine control capability is illustrated by fracture observations in mortar, cement paste and tungsten carbide‐cobalt.