PLASTIC-FLOW OF A TUNGSTEN-BASED COMPOSITE UNDER QUASI-STATIC COMPRESSION

A micromechanics study is carried out on the plastic flow of a tungsten ''heavy alloy'' under uniaxial compression. The alloy-composed of a continuous tungsten phase in a tungsten-nickel-iron ''matrix''-is modeled as a dual-phase composite, with the tungsten phase approximated by aligned, uniformly distributed and equal-sized particles. The stress-strain behavior of each phase is assumed to be power-law hardening of the Ramberg-Osgood type. Stress-strain curves of the composite under uniaxial compression are computed numerically using several cell models representing different tungsten particle shapes. It is found that the overall stress-strain behavior of the composite is essentially independent of the particle shape. However, the character of the local plastic deformation changes dramatically with the inclusion geometry. Two simple formulae are given that approximate the overall flow behavior of the composite in terms of the tungsten volume fraction and the behavior of the individual