Originally Posted by grumpus

It would be interesting, but you can cool with dry ice or liquid nitrogen, or those pipe freezers that plumbers use on water pipes - the challenge would be to maintain a steady heat gradient while welding, as you can't chill the weld pool. But I suspect it's not a weldable alloy anyway.

Indeed - whether steel or aluminium, good forged ends are remarkably tough. OTOH early bonded frames tended to be rather flexy and make worrying noises.