Particle Deformation During Cold Isostatic Pressing of Metal Powders

Abstract

A series of mono-size −125 + 106 um metal powders of differing hardnesses and work-hardening capacities were isostatically compacted over a pressure range 0–770 MPa (0–50 tonf in⁻²). Particle plastic deformation commenced rapidly in all powders where densification is at first governed by the yield stress of the material and later by its work-hardening capacity and hardness. Powders of high work-hardening capacity and low hardness densified more efficiently and vice versa. Plastic deformation occurred more homogeneously in spherical powders the geometry of which progressively changed to that of an ideal dodecahedron. In the more irregular powders particle deformation occurred more intensely at surface irregularities, which led to a less homogeneous form of particle flattening.