Effect of Impurity Hydrogen on the Void Formation Prior to Fracture in Aluminum

The behavior of internal hydrogen during the deformation of Al specimens with two impurity H levels was studied by means of trace gas analysis during tensile testing and tritium autoradiography in the strained specimens. The reduction in the impurity H content increased the ductility and decreased the amount of H gas evolved on fracture. The tritium autoradiography revealed that most of the impurity H atoms in the specimen were brought to the intersection of the slip planes with the specimen surface, indicating H transport by moving dislocations.