Superlega a base nichel
Materiale a base nichel ad alta resistenza meccanica a caldo per sollecitazioni meccaniche e termiche estreme, come quelle nei motori aeronautici.
Nickel-based materials are tough and have high-temperature strength, but they're tricky to weld. The main danger is hot cracking because impurities like sulfur gather at the grain boundaries. With precipitation-hardening grades, there's also the risk of stress cracks during cooling or heat treatment. You need to have the sheets and wire absolutely clean, otherwise you'll get porosity and brittle spots. Use suitable shielding gas and a filler material that isn't crack-prone. Keep the heat low, weld without much weaving, and don't let the part get too hot between passes. After welding, depending on the alloy, you either just stress-relieve anneal or properly solution treat and age. Heat up and cool down slowly, otherwise the part will crack.