Characterization and Mechanical Behavior of Sintered Al-Mg Powders

Abstract

The resolution of the work is to relate the characterization and mechanical properties for argon atomized Al-1wt%Mg powders through and not through lubricant 1 wt% graphite. Pure nitrogen sintering was accomplished and the effect of sintering atmosphere for the mixed Al-1%Mg powder compacts was examined. One weight percent graphite was premixed with the powder as a lubricant for the first set samples. However, no graphite was used for the second set specimens. As a sintering aid, 1wt% Mg was enhanced for both group materials. Compaction of the specimens was achieved using a hand operated hydraulic press and a floating rectangular die. First set specimens were pressed to green densities of 92.5 and 93.5% by pressures of 440 and 495 MPa, respectively. In the second set (no graphite) samples, 94% green density was achieved using the similar compaction pressures. Sintering and de-lubrication ensured in a horizontal tube furnace with a high purity nitrogen atmosphere. Green & theoretical density increased with the increment of compaction pressure. Residual macro & micro porosity was present in all sintered samples under every sintering condition. Average sized pores and small interrelated micro-pores at grain boundaries were observable when lubricant was enhanced which reduced the sintered densities due to a wide burn off range leaving residual porosity.