Distribution of Substitutional Alloying Elements and Interstitial Impurities in In Situ Multicomponent Composites Based on the Nb–Si System

Abstract

The distribution of substitution alloying elements in the structure of hexagonal silicide Nb₅Si₃ of the γ-modification, which serves as a reinforcing phase of the composite, and in the Nb solid solution matrix of a high-temperature natural composite based on Nb–Si is studied. Studies were carried out on samples in a cast state and after homogenizing thermal treatment. A structural model of the γ-modification of silicide Nb₅Si₃ is constructed. On the basis of the crystal-chemical analysis of the structure of hexagonal silicide, possible causes of phase instability of the composite after thermal treatment are revealed.