Hierarchical simulation of plastic deformation and fracture of complexly alloyed brass

Abstract

The paper deals with simulating plastic deformation and fracture of the constituents of complexly alloyed brass in upsetting under the plane strain state in view of their geometry, mechanical properties and the stress state during deformation. The peculiarities of the formation of a net of localised strain bands are discussed. It is demonstrated that brass deformation is mainly due to the malleable matrix and that it is brittle silicide particles that fail. Stress non-uniformity in silicides has been detected with the presence of both tensile and compressive normal stress areas in them. Stress stiffness coefficient distribution functions have been constructed, and a relationship between the ultimate strains of brittle silicide particles in the soft phase and the stress stiffness coefficient has been defined. The dependence has been used to simulate damage accumulation in the silicides before fracture during upsetting under plane strain. The probability of silicide fracture under deformation is shown to be reducible due to the use of stress states offering a high level of macroscopic compressive stresses – high enough to minimise zones with prevailing tensile stresses in the silicides.