Production of nano-sized grains in powder metallurgy processed pure aluminum by equal channel angular densification (ECAD) and equal channel angular pressing (ECAP)

Abstract In this study, pure aluminum powders were turned into bulk material using equal channel angular densification (ECAD)/equal channel angular pressing (ECAP) and further deformed up to 16 passes at 100 °C. For comparison, pure aluminum powders were also compacted in a mold without ECAD/ECAP process at the same temperature. The microstructures were characterized using TEM for grain size and shape measurements. In general, the grains were finer in the specimens processed by ECAD/ECAP than in the compacted specimen without ECAD/ECAP process. The high density which is very close to the full density of pure aluminum (2.7 g × cm -3 ) was reached at the second pass of ECAD/ECAP. By the application of ECAD/ECAP process, severe plastic deformation enabled particles to be compacted into fully dense materials at much lower temperatures and shorter times, compared to the conventional sintering process. The ECAD/ECAP process was shown to provide an effective method for producing nano-sized grain and nearly full densification in aluminum powder.