Dislocations and plastic deformation in molybdenum disilicide

A composite of MoSi2 (reinforced with SiC whiskers) has been deformed at high temperatures and the resulting dislocation substructure studied by means of transmission electron microscopy (TEM). Classical g · b analysis of the dislocations in the MoSi2 matrix has shown that the Burgers vectors are left-angle 100 right-angle, left-angle 110 right-angle, and 1/2 left-angle 111 right-angle which are the shortest lattice vectors in the body-centered tetragonal lattice. Trace analysis showed that there are numerous possible slip planes for each of the determined slip directions. This result suggests that various operative slip systems can contribute to the deformation, depending on the orientation of the particular grain with respect to the stress state