"the cost of titanium will drop by a factor of two to five"
Steel is easy to weld (depends on type, but generally)
Aluminum is harder
Titanium is even harder. It reacts with nitrogen.
Steel is relatively easy to machine
Aluminum can be even easier.
Titanium is very hard.
Sounds like there might be some roadblocks on wide spread adoption of titanium still, even if the raw material gets cheaper.
The SR-71 was largely constructed out of titanium since the whole airframe heated up to high temperatures in high speed flight.
The maintenance facilities had welding stations that had nitrogenless atmospheres under a "bubble".
>Steel is relatively easy to machine Aluminum can be even easier.
Mechanical engineer here. This depends heavily on the alloy you're dealing with. Many Aluminum alloys are so soft that they'll actually melt and subsequently bond to the tool surface when they're being cut/ground/sanded/etc.
Also Aluminum tends to have a very low shear strength which means it won't hold a thread the way most steels will - this is why you typically see rivets in aircraft skin.
As I discovered the first time I tried to machine an aluminum extrusion. I was used to 6061 alloys that machined very well dry, but this "hardware-store grade" extrusion softened enough to weld itself to a nice Niagara endmill, ruining it :-(
Steel is easy to weld (depends on type, but generally) Aluminum is harder Titanium is even harder. It reacts with nitrogen.
Steel is relatively easy to machine Aluminum can be even easier. Titanium is very hard.
Sounds like there might be some roadblocks on wide spread adoption of titanium still, even if the raw material gets cheaper.
The SR-71 was largely constructed out of titanium since the whole airframe heated up to high temperatures in high speed flight. The maintenance facilities had welding stations that had nitrogenless atmospheres under a "bubble".