Nickel addition alloys
Technology for receiving nickel addition alloys (nickel - 20-25%yttrium, nickel - 20-25%lanthanum) to produce super heat-resistant alloys used for aircraft of 5th generation is developed. Technology includes component alloying in arc furnace having inexpensive tungsten electrode and cooper water-cooled mold in argon atmosphere. Technology allows producing high homogeneity alloys having minimum liquation inhomogeneity, as well as minimum contamination during the process of melting. Addition alloy is introduced into heat-resistant alloy on the basis of 0,2% of rare-earth metal (REM). While using addition alloy, REM assimilability is increased by 40%. Rare-earth metal introduction provides low content of impurities (oxygen, nitrogen and sulfur) in heat-resistant alloy due to full and stable assimilability of REMs, which are effective deoxidizers and desulfurizers.
Results of long-term strength test of monocrystal alloys melted using addition alloys, demonstrated large creep-rupture life values for new generation heat-resistant alloys.
Recently, ruthenium is used as nickel addition alloy to increase operating temperature in aircraft engine combustor. Using addition alloy instead of pure ruthenium allows increasing its assimilability by 10%.
For all addition alloys, technical conditions are developed and approved. To meet existing and perspective demands, special area with modern equipment is designed and put into operation in the institute.