Thoery of Plasticity for Porous Metals

Abstract

The basic equations are proposed for plastic deformation of porous metals such as sintered metal powders or metal powder compacts. The porous metal is assumed to be made up of a homogeneous metallic material and unformly distributed pores. The following equations are obtained from the Levy-Mises equatioins, (dε1-dε2)/(σ1-σ2)=(dε2-dε3)/(σ2-σ3)=(dε3-dε1)/(σ3-σ1)=(3fdευ)/(2σm/f)=(3dεeq)/(2γσeq) where γ is the relative density of the porous metal, f a function of γ, the subscripts 1, 2 and 3 represent the principal directions, σm=(σ1+σ2+σ3)/3 and dευ=dε1+dε2+dε3. The theory shows a good agreement with the experimental results for sintered copper powder compacts.