Influence of Particle Size on the Phenomena Responsible for Densification during Uniaxial Cold Compaction

摘要

In this work the behaviour of austenitic stainless steel powder column during uniaxial coldcompaction was investigated; experiments were carried out in a hydraulic press, using powdermixtures with different particle size. The powders were compacted to the same green density;moreover, compaction tests at intermediate forces were carried out, and the data continuouslyrecorded by the press in terms of force and displacement of the axes were analysed, allowing todistinguish the contribution of the reversible phenomena (elastic deformation of powders and tools)and of the irreversible phenomena (rearrangement and plastic deformation of the powders). Ananalytical model describing the trend of reversible and irreversible displacements versus the appliedforce was proposed. The influence of particle size on the resistance to rearrangement, elasticdeformation and plastic deformation was therefore experimentally determined. The results areimplemented into a knowledge base data, to be used as a design tool for PM structural parts.