Deformation and strengthening of sintered ferrous material

Plastic deformation is an important process to improve performance and obtain final product for sintered powder materials. Sintered ferrous material is widely used in many engineering departments and its deformation characters are typical for most of sintered powder materials. The influential factors, such as deformation strengthening, instantaneous and initial relative densities etc., on following yield strength is studied; an approach to determine the plastic stress coefficient and hardening exponent is derived, based on yield criterion and strengthening laws of plastic deformation of sintered powder materials and uni-axial compression experiment of sintered ferrous cylinder specimens. A unified form of yield criterion function is obtained, in which initial and following yield of sintered ferrous material are expressed.