High pressure triaxial facility for powder compaction

A high pressure triaxial testing facility has been developed to investigate the compaction behaviour of powders. The facility can test cylindrical powder specimens up to hydrostatic pressures of 700 MPa and superimposed axial loads up to 1100 MPa, which are applied using two independent servo systems controlled by a computer. The deformation of the specimen and the loads are measured directly using devices placed in contact with the specimen in the pressure environment. This paper is concerned with the description of the system and presents preliminary test results for an iron based powder. Isostatic compaction, consolidated triaxial compaction, and simulated closed die compaction tests were performed. The specimens are compressed from a state of dense random packing of the particles to near full density. The results show good reproducibility. The behaviour of this powder shows similar trends to data published in the literature, however, differences in terms of dilatant behaviour were observed.