Forging of ultrafine grained commercial purity titanium orthopaedic implants

The increasing demand for advanced orthopaedic implants increases healthcare spending worldwide. One possible way of limiting this cost is through replacing titanium alloy Ti-6Al-4V ELI, often used for orthopaedic implants, with pure titanium, which is cheaper and more biocompatible. However, pure titanium is not strong enough to be used in such applications. The solution is to increase its strength by refining its grain structure by severe plastic deformation. This paper describes an attempt to produce ultrafine grained commercial purity titanium grade 2 and characterise its deformation behaviour and structure evolution in subsequent uniaxial compression testing. The final material is then forged into a scaled-down femoral stem. After forging, the femoral stem had lower tensile strength than Ti-6Al-4V ELI but identical high cycle fatigue strength. The proposed approach enables cost reduction realised through cheaper material, dramatically reduced forging temperature, longer tool life and avoiding chemical etching after forging.