Characterization of Zinc Powder Compactions: Factors Affecting Mechanical Properties and Analytical Powder Metallurgy Models

In this study, the effectiveness of analytical models which attempt to predict the density of unsintered powder metallurgy (PM) compacts as a function of consolidation pressure is investigated. These models do not incorporate the nonuniform densification of powder compacts and may insufficiently describe the pressure/densification process. Fabrication of uniform and nonuniform Zinc (Zn) tablets is conducted to assess the validity of the pressure/density model developed by Quadrini et al. (Quadrini and Squeo, 2008, “Density Measurement of Powder Metallurgy Compacts by Means of Small Indentation,” J. Manuf. Sci. Eng., 130(3), pp. 0345031–0345034). Different tablet properties were obtained by varying the compaction pressure and fabrication protocol. Density gradients within Zn tablets result in a spatial dependence of Vickers microhardness (HV) throughout the fabricated specimen. As a result, micro-indentation testing is used extensively in this study as a characterization tool to evaluate the degree of nonuniformity in fabricated Zn tablets. Scanning electron microscopy (SEM) is also employed to verify tablet density by visual examination of surface porosity as compaction pressure is varied and sintering is applied.