Used for thousands of years for its exceptional malleability, castability and corrosion resistance, copper and its alloys are easily processed with ESF. Thanks to a wide variety of commercial powders available with a large spectrum of particle sizes and compositions, electro-sinter-forged copper alloys and composites can be an inter- esting alternative, or a breakthrough innovation, compared to common cast, forged and machined products.
Typical sintered materials may be:
- Nano-crystalline copper
- Oxyde dispersion strengthened (ODS) copper
- Copper-graphite composites
- Copper-diamond composites
- Bronze-diamond composites
High purity, dense, hard copper with an average crystallite size of 20-40 nm was produced with ball milled dendiritic powders followed by capacitor discharge sintering. Exceptional hardness values beyond 180 HV0,5 with a conductivity of 79% IACS (1,33*10^-8 Ohm/m) have been obtained in the not yet optimized system. The material presents a yield strength of 450 MPa and could plastically compressed to a strain over 40% before fracture.
Fig.1 – XRD spectra of as received Cu powders and ball milled powders.
Fig.2 – TEM image of nanocrystalline discharge sintered copper
Fig.3 – TEM image of nanocrystalline discharge sintered copper at higher magnification
Fig. 4 – Stress-strain compression curve for nanocrystalline discharge sintered copper
