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Tadd,
Most Alpha/Beta Titanium alloy have a relatively high work hardening exponent, but not as high as Austenitic Stainless steel.
It is this fator that means you have to take great care in the type and form of cutting tool used for machining. If not machined correctly they will easily gall or suffer other surface problems.
Shot peening is generally beneficial to the fatigue life of high strength titanium components but needs to be carried out with some degree of expertise and using the same parameters as you would for a steel may not be the best thing to do.
It is quite possible that careful shot peening may eliminate the slip band intrusions and extrusions that initiate fatigue cracks and effectively re-life the component but I would like to do a little more research before I am 100% confident that this is true.
Anodising, unfortunately isn't a great idea for components that suffer fatigue loading.
As with most hard surface layers anodising does reduce the fatigue life of a component even if only by a few percent.
Titanium is also quite good at picking up atomic hydrogen and if the voltages in the cell used for anodising aren't well controlled nascent hydrogen will enter the lattice and reduce the materials ductility and significantly increase notch sensitivity.
Using titanium for cranks is an altogether differnt issue. Although Titanium has good strength and low density its E and G Modulii are around 50% of a steel component. This means for a given forcing function (Inertia and Gas Torques) the deflection of a given crank would be about double that of steel and this may be a real issue.
The use of a bearing on a Titanium journal wouldn't be great either as the rubbing that inevitably occurs on starting and stopping would almost certainly cause damage.
It is common practice to coat Titanium Couplings that have to opearte with rubbing seals with Chromium Oxide but I just don't know how well this would work with a journal bearing.
I gusee a specialist company such as Poeton may have a view.
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