I think this might be what they are talking about. Brilliant video, the story just builds and builds and builds. https://youtu.be/K4yCXIZ32lk

Are there other gasses that could be used. E.g some of the noble gasses like argon or neon?

A few years ago the same thing happened to me. There was someone who wasn’t doing to good, on top of the station building on the next stop along throwing tiles and other things off. The operator got some replacement busses, that I couldn’t get as I had my bike. So I just sat there with someone else who could get on as they had their dog. For about 4-5 hours. Sucked allot as I was tired, the dog was cute though.

Metals are made of crystals, they usually defourm along the grain boundaries and fatigue cracks also grow along them. By eliminating those boundaries you reduce the chance for fatigue cracks and make the overall blade stronger.