Electroimpact compaction of pm components

Abstract

An explosive cartridge gun was used to accelerate a cylindrical impacter to a velocity of 120 m s−1 on to a powder specimen contained in a thick walled cylindrical die. The impacter also acted as a short circuit switch to discharge stored high voltage (up to 10 kV) electrical energy through the powder during the impact. In this way, relatively high density and tougher powder metallurgy components were obtained as compared with those from electrical discharge or impact processes applied individually. These compacts exhibited mechanical interlocking as a result of impact as well as interparticle welding due to electrical discharge. The steel impacters were partially insulated to vary the duration between the instant of electrical discharge and that of maximum compressive force. The best compact was found to be produced when the electrical energy was discharged at the instant just before maximum dynamic compaction pressure occurred. PM/0426. © 1987 Maney Publishing.