Desulfurization of Single-Crystal Nickel Superalloys with Vacuum Melting

Resumo

An unfavorable effect is established for a high sulfur content on the high-temperature strength properties of single-crystal alloy ZhS36 in stress-rupture tests based on 500 h, on the average number of cycles to failure during low-cycle fatigue tests, and also on coated alloy isothermal heat resistance. The unfavorable effect of sulfur may be overcome by alloy refinement with lanthanum followed by melt filtration through a ceramic foam filter during casting. Metallographic study confirms the results obtained for the effect of alloy refinement with lanthanum.