Are there other sources for titanium if Putin decides to "counter-sanction" the U.S. and cut off exports?
China is a major global source of titanium, but it tends to consume what it produces. Then there's Ukraine, which produces titanium in Zaporizhzhya -- located between Russian-controlled Donetsk and Russian-reclaimed Crimea. U.S. and EU titanium users may want to cross Ukraine off their long-term supply list. U.S. titanium suppliers like RTI, Allegheny Technologies Inc. and TIMET may push to surge their production lines, but how quickly -- and how much -- is uncertain. But doesn't the U.S. Defense Department maintain a metals stockpile? It does. And between 1998 and 2005, the National Defense Stockpile sold off its titanium reserve -- from 34,800 metric tons down to zero. (Where did the proceeds go? By order of the U.S. Congress, the Pentagon was instructed to implement the "sale of titanium from the National Defense Stockpile and allocate funds to the establishment of the World War II Memorial.")
With the Pentagon's cupboard bare, Boeing and United Technologies have little choice but to bulk-buy titanium parts -- as long as their Russian supplier is willing to sell.
But what happens if Vladimir Putin decides it's time to escalate the sanctions war as he refuses to deescalate in Ukraine?

w 1923r. Boncz-Brujewicz ukończył prace nad 25 kilowatową lampą generacyjną o wodnym chłodzeniu anody; lampa ta posiadała na owe czasy największą moc w świecie, a budowa jej jest wzorem dla wszystkich cudzoziemskich firm lampowych aż po dzień dzisiejszy.

Należy jednak pamiętać że były to czasy konfrontacji.