A preliminary study of the ductile‐brittle transition under impact conditions in material from an octahedrite

Charpy impact specimens prepared from a piece of the octahedrite Henbury have been tested at 195° and 300°K in a pendulum hammer machine. The energies absorbed during fracture were 5.0 ft lb (6.9×104 dyn cm) and 20.0 ft lb (2.8×105 dyn cm), respectively. Thus the specimen tested at the lower temperature was almost totally brittle, while that tested at the higher temperature exhibited significant ductility. These results provide preliminary verification of a recent prediction (Johnson and Remo, 1974) that material from octahedrites should exhibit a ductile-brittle transition, with the transition to brittleness occurring, under impact conditions, at about 200°K.