Orientation Relationships and Lattice Misfit between a Nb Matrix and γ-Silicide in a Nb–Si Composite

Resumo

Orientation relationships {110}_Nb||{100}γ and 〈111〉_Nb||〈001〉γ between the crystal lattices of the Nb solid solution and particles of γ-silicide Nb₅Si₃ were determined by transmission electron microscopy. The following two types of matching planes were found: {110}_Nb||{100}γ and {111}_Nb||{001}γ. The former planes form steps at an angle of 120°. The correctness of the calculated orientation relationships was confirmed and these relationships were compared with experimental electron diffraction patterns using methods of mathematical modeling, which enable one to obtain superimposed electron diffraction patterns of several phases and tilt the model crystal. An interface model in two sections was constructed. The morphology of the interface between the particle and the matrix was explained in terms of structural features. The lattice misfit between the matrix and γ-silicide was calculated.