The UK’s Defence Science and Technology Laboratory (Dstl) has developed a new process for producing titanium working with the University of Sheffield. This reduces the currently 40 stage process to only two steps and is expected to half the cost.
Titanium has a similar strength to steel but is half the weight. It doesn’t suffer from fatigue issues, which can cause aluminum to suddenly and catastrophically fail, and it is highly resistant to corrosion. It also has far better damage tolerance to carbon fiber. For all these reasons it is widely used in aircraft and spacecraft. A typical use is in aircraft undercarriage which is in many ways similar to a bicycle frame is its material requirements. However, at around ten times the cost of high-quality steel, titanium is currently reserved for only the most exotic bicycle frames and components.
The process, referred to as FAST-forge, consolidates titanium alloy powders into components. These only require machining for highly toleranced features (“near net shape”) and have mechanical properties similar to forged components. Field assisted sintering technology (FAST) is used to melt the powdered material forming a shaped billet, at this stage, it does not have the required complexity of geometry for many components and its ‘grain structure’ means that it is not as strong as a high-quality titanium component. However, the billet can then be hot forged in a single step to give a near net shape component with the required mechanical properties.
A number of new manufacturing technologies are currently becoming available which look set to enable lower cost use of more exotic materials as well as low volume and bespoke designs. For example 3D printing in titanium and in carbon fiber. Put this together with the coming graphene reinforced composites and we can expect bikes to be getting considerably lighter over the next few years