Yield and compaction behavior of rapidly solidified Al–Si alloy powders

In order to obtain high quality products in powder metallurgy, it is important to control and understand the densification behavior of metal powders. The effect of the characters of powders on the compaction behavior was investigated in this study by using three types of Al–Si powders produced by gas atomization, centrifugal atomization and twin roll-pulverization. The shape of the powders was a major factor in the apparent or tap density, and the deformation resistance of the matrix of the powders was a major factor in compactibility. Hanʹs yield function ((2+R2)J′2+(1−R2)/3 J21=Y2R=R−RT/(1−RT)m Y20) for metal powders was simplified from the relationship based on the experimental results of copper powders. In spite of some assumptions, the calculated compaction curves using a new yield function was in accordance with the experimental results.