Cold compaction of iron powders: relations between powder morphology and mechanical properties. Part II. Bending tests: results and analysis

The purpose of this study is to determine the green strength of compacts made from iron powders and to understand how it correlates with pressure compaction and powder morphology. Two different types of powders have been tested by means of three-point bending (TPB) tests performed until fracture. In a classic approach, the obtained maximum loads are used to calculate a transverse green strength. In the compaction pressure range considered (from 100 to 290 MPa), relative densities between 48% and 71% are obtained and increased linearly together with compaction pressure. The compacts made of spongy-like particles give better green strengths than the compacts made of spherical particles. However, the global load/displacement response of the TPB tests cannot be explained by a symmetric behaviour in tension and in compression of the tested materials.