ON A NOVEL METHOD OF INCORPORATING AN INTERNAL STRUCTURE INTO GREEN POWDER METALLURGY COMPACTS USING DIE COMPACTION

Abstract

A novel method of producing die compacted powder metallurgy components with fully en-closed internal structures was developed. The physical characteristics of the compacts were evaluated by measuring bulk density, internal density gradients and compressive green strength. Additionally, a finite element simulation was developed to evaluate the compaction process of the internal structure compact. The internal structure compact displayed the anticipated lower bulk densities due to the less dense internal structure than a conventional powder metallurgy compact, however; higher local densities were found within the internal structure compact at all compaction pressures. Compressive green strength characteristics showed unique results where the strength in-creased up to 300 MPa compaction pressure, however; at 400 MPa there was a distinct plat-eau in green strength. This phenomenon was attributed to an increase in differential shear stress around the internal structure with a minimal increase in density from 300 MPa to 400 MPa.