Energy relations in the compaction of binary powder mixtures

Conclusions

• 1. In the compaction of powder mixtures, energy absorption takes place as in the case of pure metals. Relative absorption at first increases, attains a maximum, and then falls off. At high degrees of densification, differential relative absorption becomes negative because of a marked strength loss experienced by materials being compacted.

• 2. Energy absorption is not an additive function of concentration. This finding is supported by a hypothesis postulating the formation of surface solid solutions in the contact zones of powders being compacted.

• 3. Additions of Fe, Cu, and Zn in Al lower energy absorption.

• 4. Additions of Al in Fe, Cu, and Zn increase energy absorption owing to the high absorptive capacity of Al.

• 5. The thickness of the surface solid-solution layers, as calculated from the drop in energy absorption, is of the order of 0.4μ.