THE INFLUENCE OF ACTIVATION PREPROCESSING OF B₄C AND SiC POWDERS MIXED WITH Al ON THE PHASE COMPOSITION, STRUCTURE, AND PROPERTIES OF HOT-PRESSED COMPOSITES

Abstract

The paper examines how the conditions of activation preprocessing (dry and wet grinding) of В₄С–Al and SiС–Al powder mixtures in a planetary-ball mill influence the formation of phases in the mixtures and the phase composition, structure, and mechanical properties of the associated hot-pressed materials. It is shown that dry grinding, unlike the conventional powder charge preparation method, induces the mechanical synthesis of new phases in the В₄С–Al powder mixture along with its mechanical activation. The formation of new phases in the SiС–Al powder mixture does not depend on the conditions of activation preprocessing. Secondary phases form in the hot pressing of the В₄С–Al and SiС–Al powder mixtures. The structure and micromechanical characteristics of the materials indicate that dry grinding of the В₄С–Al and SiС–Al powder mixtures has a greater activation effect on the hot-pressing densification process, structural uniformity, phase composition, and mechanical properties compared to the conventional powder charge preparation method.