Process investigation and mechanical properties of electro sinter forged (ESF) titanium discs

Abstract

Classified as an electric current–assisted sintering (ECAS) process, electro sinter forging (ESF) represents a sintering process following the resistance heating approach. The powder is simultaneously compacted and heated in a closed-die setup. The heating is generated by the Joule effect from the electrical current. Near net shape components of conductive materials are made in the closed-die setup within a short process time (100–400 ms). The final relative density is an important quality measure for the sintered parts. In the present work, samples of commercially pure titanium are produced with up to 98% relative density by optimisation of the main process parameters, namely electrical current density, compaction pressure and sintering time. Metallographic observations revealed that porosities were mostly found at the perimeter of the sintered samples. Mechanical testing by μ-Vickers hardness test, uniaxial compression and indirect tensile tests showed improved properties of the material with increasing density. The achieved mechanical properties were compatible with the theoretical values for bulk titanium.