Determination of the stress-strain state when examining the limiting plasticity of porous parts

Workability studies on cold upsetting of sintered copper alloy preforms

“…Pokorska 12 determined the apparent yield stress for P/M materials by considering three kinds of materials include iron, copper and aluminum. The deformability of sintered materials was evaluated 13 on the basis of the limiting plasticity diagrams, characterizing the variation of the strain of the material to fracture in relation to the parameter of the stress state. Aubertin and Li 14 proposed a multi-axial yield criterion that can be applicable to variety of materials and loading state, its main advantage is explicitly porosity dependent.…”