Mechanical properties and microstructures of low cost β titanium alloys for healthcare applications

Titanium alloys are the best choice of metallic materials for biomedical and healthcare applications due to the combination of their excellent mechanical properties and biocompatibility. However, the usage of titanium alloys is limited due to its high cost. In order to reduce their cost, two new titanium alloys, Ti-4.3Fe-7.1Cr (TFC alloy) and Ti-4.3Fe-7.1Cr-3.0Al (TFCA alloy), for healthcare goods such as wheelchairs have been recently developed using low cost ferro-chrom elements. The microstructure and mechanical properties of both alloys subjected to solution treatment in the beta field or thermomechanical treatment were investigated, and then evaluated for their potential to be used as wheelchair materials. The specific strength and fatigue ratio of TFC and TFCA alloys are much greater than those of the existing wheelchair materials. Unrecrystallized grains obtained in the alloys at low solution treatment temperature can be eliminated by increasing solution treatment temperature or by conducting thermomechanical treatment. The latter method is recommended because it also gives a better strength and ductility balance as a result, mainly, of grain refinement. However, TFCA alloy seems to have more potential to be used as wheelchair materials compared to TFC alloy because of its better workability and post thermomechanical treatment ductility.