FAST-forge − a new cost-effective hybrid processing route for consolidating titanium powder into near net shape forged components

Reducing the high cost of titanium to a level where it can compete with currently used commodity metals offers opportunities to many industries to exploit its excellent combination of properties to improve performance or reduce weight. The key to decreasing cost is to reduce the number of processing steps to go from ore to component, as well as material wastage from excessive machining. This paper describes a new solid-state hybrid manufacturing route, termed by the authors as FAST-forge, for converting titanium alloy powder into components with wrought properties in two steps; utilising field assisted sintering technology (FAST) to produce a shaped preform billet that is finished to near net shape by a one-step precision hot forge. The route has been demonstrated at the laboratory scale using Ti-6Al–4V hydride-dehydride powder by producing fully consolidated, microstructurally homogeneous, double truncated cone specimens directly through FAST, which were then upset forged at a range of temperatures and strain rates. The microstructural evolution and forging behaviour of the Ti-6Al–4V after FAST consolidation is similar to conventional melt, multi-step forged product. Break up of primary α at high strains was observed at 950°C and 0.01 s−1, 0.1 s−1, and 1 s−1. There is good agreement between finite element modelling of the hot forging and the experimental data, which will enable more complex shaped geometries to be produced via the proposed FAST-forge route in future. Such a route could be used to consolidate powder from a lower-cost alternative extraction method to become a disruptive technology that will enable a step-change in the economics of titanium components.