On the calculation of deformation curves for two-phase cermets

Abstract

Analytical algorithms for the construction of tensile and compression stress-strain diagrams of two-phase cermets are proposed, which are based on the concept of mean stresses in the phase volume and physical equations of the theory of small elastoplastic strains. The deformation properties and strength of cermet are supposed to depend on such parameters of its microstructure as mean size and coefficient of variation of solid phase grain-size distribution, contiguity coefficient of solid phase grains, and mean thickness of the metal phase inter-layers. A numerical analysis of the characteristic parameters of deformation curves for WC-Co hard metals has been carried out over a wide range of cobalt concentration and carbide grain size. A good agreement between the theoretical values of ultimate tensile and compression strength and known experimental values has been established. The constructed model deformation curves for hard metals may be regarded as alternatives to the corresponding experimental curves of stress against relative change in specimen length.