Compressibility of heterogeneous powder mixtures in rolling

Conclusions1.The relative density of composites consisting of a ductile matrix and brittle fillers whose yield stress exceeds that of the matrix is inversely proportional to the surface area of unit volume of the inclusion particles. The coefficient of proportionality is a structure-sensitive magnitude and depends on the volume fraction of the filler in the mixture, the shape and strength of its particles, and the isotropy of the mixture.2.The factor influencing the compressibility of composite materials most is, other things being equal, the strength of the inclusion particles. Rupture of filler particles creates a situation in which further densification of the mixture becomes possible.3.In the case of fillers whose strength characteristics are lower than those of the matrix, stress concentration may increase up to its critical value, which depends on the volume fraction of the filler and the external stress. Exceeding this critical value is accompanied by local stress relief, which results in strip rupture — spontaneous growth of a large crack.