MPFEM investigation on densification and arch bridge structure during iron powder compaction with different powder shapes

Abstract This study addresses the underexplored evolution of the key arch bridge structures that affect powder compaction. A coupled qualitative and quantitative analysis of densification and deformation is conducted through 2D MPFEM simulations of uniaxially compressed pure iron powders with sphere, hexagon, and strip shapes. Results showed that powder densification was mainly divided into three stages: rapid consolidation (≤40 MPa), plastic deformation (40–460 MPa), and decelerated densification (460–600 MPa). The strip powder with a smaller aspect ratio achieved superior densification, evidenced by the highest relative density and coordination number evolution, along with the lowest final equivalent plastic strain (0.0943) among the morphologies studied. As the compaction pressure increased, the arch bridge structure initially increased and then fluctuated showed a fluctuating trend overall. The strength rose sharply initially before its growth rate diminished beyond 100 MPa. The bending angle transitioned from an upward trend to a fluctuating downward trend, and the direction angle of the arch bridge structure fluctuated around 90 ° . In addition, the strength of the sphere arch bridge structure was high, and the directional angle of the strip arch bridge structure was small. In summary, strip powder with a low aspect ratio offers notable benefits in enhancing compaction uniformity, lowering plastic strain, and alleviating arch bridge effects, thus furnishing valuable guidance for optimizing high-performance powder compaction processes.