Effects of lubricants and compacting pressure on the processability and properties of aluminum P/M parts

Lubricants are generally admixed to metal powders to ease compaction and minimize the interaction between the tooling and the compact during ejection. The type and concentration of the lubricant have a significant impact on the processability and the characteristics of the material. While extensive work has been performed with iron-based mixes, relatively few studies have been published on the effects of lubricants and shaping conditions on the processing behavior and characteristics of aluminum (Al) components fabricated by powder metallurgy (P/M).

This paper presents the effects of the lubricant type (ethylene bisstearamide vs. polyethylene wax), the lubricant concentration (0.7–1.5 wt.%), as well as the compacting pressure (138–413 MPa) on the powder characteristics and the properties of press and sintered 2xxx series aluminum alloy specimens (AMB-2712). Compaction and ejection characteristics, surface finish, green density and strength, dimensional change during sintering, sintered density and mechanical properties are presented and discussed.