On website of the Office US patents found an interesting document filed by Apple.
What did they come up with
The patent talks about that in future «apple» titanium cases may appear in products, as it describes a way to solve the problem of the unaesthetic appearance of such material.
So, anodized aluminum, which is now used in MacBook laptop cases are not durable enough. Have there is no titanium problem, but products from him «aesthetically unattractive».
But Apple has found a solution: with using etching and chemical process, the titanium case can be given a normal appearance.
IN the documentation also says that hulls from of this material is suitable for MacBook laptops, iPad tablets, iPhone smartphones and
Source: Patently Apple