YIELD BEHAVIOUR OF COLD COMPACTED COMPOSITE POWDERS

Abstract A triaxial test rig is used to study the axisymmetric cold compaction behaviour of powder composites comprising aluminium with silicon carbide reinforcement, and lead shot with steel reinforcement. Under hydrostatic loading the pressure–density response shows an increase in strength with increasing volume fraction of reinforcement. For a given volume fraction of inclusions, the compaction pressure to achieve a given relative density increases with diminishing size of reinforcement. The yield surfaces are measured after isostatic and closed-die compaction; it is found that the shape depends upon the deformation path, with greatest hardening along the loading direction. The effect of reinforcement on the overall shape of the yield surface is found to be minor.

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