Influence of Scandium Alloying during Metal Smelting on the Mechanism of High-Temperature Deformation of Candidate Nickel Alloys for Reactor Engineering

The results of materials investigation including metallographic and fractographic comparative analyses of the physical properties and structure of deformed nickel alloys with a known composition (with and without scandium) are presented. Based on structure analysis data and their comparison with data of short-term mechanical tests of the alloys at 750°C, a mechanism of high-temperature alloy fracture has been discovered. Recommendations ate given for using alloys with a scandium microaddition as structural materials intended for the manufacture and application of products operating in the temperature range 600–800°C. The advisability of using scandium-containing KhN62M-VI nickel alloy is confirmed by its higher mechanical performance and also by the fact that it is not prone to brittle fracture in tests carried out at 20 and 750°C.