...and if you believe that, I've got a bridge for sale. Titanium is many things but soft it is not. It can also be alloyed with many other metals for specific purposes. One thing it definitely is though is expensive which is most likely the reason for Apple to look for alternatives. That is actually is possible to use titanium to create form-stable notebooks can be seen by e.g. the many Thinkpads which sport titanium lids and frames. I have yet to see one of these warped or bent. This is partly due to the boxy - and with that, strong - form factor but the material plays a big role as well.