Meet basalt.
Basalt fiber, formed from lava rock, lasts for hundreds of years in steady state, regardless of temperature or environmental exposure. In almost every aspect, basalt fiber is superior in function to steel and other composites-4X the tensile strength, 6X lighter and 30% cheaper than galvanized steel, 50% lower cost than aluminum and 90+% lower cost than carbon fiber.
Since basalt is not a metal and is essentially rock, it is non-conductive and does not rust or corrode like steel. Moreover, basalt has a 74% lower carbon footprint than steel and is sustainable, environmentally friendly, and safe for humans.