The Green Strength of Die-Pressed Zinc Powder

A series of fractions of zinc powder were compacted over a pressure range 0-50 tonf in-2 (0-770MN m-2). Tensile strengths of the as-pressed compacts increased with compacting pressure, the increases continuing up to 50 tonf in-2• Strength levels were higher for equivalent·compacting pressures as particle size decreased. An inversion in strength level occurred in the coarse-to-intermediate fractions over an intermediate pressure range of 20-35 tonf in-2 (309-540 MN m-2), attributed to a process of particle fracturing, based upon the work-hardening rate and capacity of the zinc. It is considered that,. initially, strength is dependent upon interparticle contact involvement, but as pressure increases and interparticle contact maximizes, strength is probably more dependent on fundamental bonding forces of attraction than on contact area.