Dislocations in energetic materials. 2. Characterization of the growth-induced dislocation structure of pentaerythritol tetranitrate (PETN)

The predominant dislocation types in crystals of pentaerythritol tetranitrate (PETN) grown from solution have been observed and characterized using transmission X-ray topography. The dislocation characterization, carried out by contrast variations, was aided and simplified by comparison of observed dislocation line directions with those calculated from the theory of preferred line directions of Klapper [Habilitationsschrift (1975). RWTH, Aachen]. With few exceptions, the dislocations observed were induced during growth. Eight different types were identified comprising all possible Burgers vectors up to and including (111). Of these, one was pure edge, the remainder being of mixed character. The relative frequency of occurrence of the dislocation types is discussed, together with factors influencing dislocation contrast and characterization.