Effect of Rare-Earth Metals on Cast High-Temperature and Corrosion-Resistant Alloy Cleanliness and Service Properties

Abstract

It is shown that addition of rare earth metals to cast corrosion-resistant high-temperature alloys facilitates a reduction in harmful impurities (oxygen, nitrogen, sulphur) and substantially increases operating characteristics. The microstructure in cast condition and after complete heat treatment is typical of hightemperature nickel alloys. It is established that exceeding the optimum REM content leads to eutectic γ′-phase melting that may cause a reduction in operating properties. The introduction of waste, including substandard materials, during melting does not lead to a reduction in operating properties.