High Temperature Nitriding Effect on Structure and Properties of Welded Nickel Superalloys

The study tested the effect of thermo-chemical treatment (high-temperature nitriding) on the structure and properties of sheet samples of welded nickel superalloys with different types of alloying: homogeneous (VZH98), aging (VZH159) and nitride dispersion-strengthened alloy (VZH171). Findings of the research show the positive effect of high-temperature nitriding on prolonged heat resistance at 1000°C for alloys VZH171 and VZH98, containing titanium. Specially selected ratio of VZH171 alloy components allows us to create a favorable microstructure throughout the entire thickness of the sample sheet in the process of thermo-chemical treatment. Finally, we found that formation of dispersed nitride particles in VZH171 alloy doubles microhardness, and soaking it at 1200 °C for 100 hours does not cause significant changes in the alloy structure.

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