Chromium Manganese and Molybdenum are not exotic but I think may be hard to source in Japan. I think the discussion is a bit off target, I have seen 4 warbirds undercarriage fail, all because they didnt lock out. I cannot imagine a landing hard enough to bend or snap the steel in a leg without the whole of the rest A/C being a write off, like the passenger plane that landed really hard and punched the undercart struts straight through the wing.