Well it should be intuitive that alkali metals are quite active metals and while not nearly as so when alloyed with more benign metals there is still a concern. Friction stir welding was developed to seam weld Al/Li tanks for one of the X programs. Thats alot of trouble to go through, if it were weldable in conventional ways they would have done it. I would imagine a head would undergo unacceptable levels of oxidation. To look for further weight reduction in vehicles turn to other denser components. This kind of thing isn't warranted unless you are at the end of the weight reduction rope and costs (include processing) justify it.
To the point of the original post, keep in mind that a controlled atmosphere would be necessary to do any work of use. We are talking argon, dry nitrogen could react with the lithium. What's the application if I may ask? Sounds interesting.
Like Jselin wrote, there is more problems concerning al-li alloys because the alkali metal like lithium addition in alloy with Al, so Li gives all technical problems, like violent reactions with water, oxygen, hydrogen at temperatures bellow 5oo C, nytrogen and so on, that will take to controlled atmosphere ellaboration (like argon atmosphere or vacuum) of alloy.Also, the limited solubility of Li in Al (4.4%-5.2%theoretically)is another problem.Y read about some alloys al-li, with addition of Germanium, that partially grow the solubility of Li.After my recognition, there is some alloys for commercially use Al-Li, like russian 1441,or american 8081,and y think also that the alloy Weldalite solves partially the problem of welding these alloy. Y'm very interested in these alloys, so if You find something useful, plese notify. Best regards , Bogdan.
