2080 – 07 – Varieties of Nickel-Based Superalloys

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Nickel-based superalloys, like most super alloys, contain a variety of other metals. While all these different types of nickel-based super alloys are heat and corrosion resistant, the slightest change in composition can give an alloy a variety of different characteristics.

Nickel-chromium-based superalloys have excellent oxidation resistance in stressful environments. They have much better creep strength than steel. It’s key to remember, though, that nickel-chromium can be hard to machine because of quick work hardening.

After the initial machining, work hardening elastically deforms either the tool or the workpiece after each following pass. This means these superalloys need to be machined with a forceful, slow cut with a hard tool.

Incorporating more elements into these super alloys alters the properties of nickel-chromium-based superalloys — sometimes positively, sometimes negatively. When you add molybdenum to nickel-chromium alloys, they become more ductile and resistant to chemical damage. Adding cobalt to nickel-chromium emphasizes the alloys creep resistance and high rupture strength.