EFFECTS OF A RARE EARTH ADDITION ON UNITEMP 901.

Abstract

The theoretical amount of lanthanum required to react with oxygen and sulfur in a molten bath of an iron-nickel base superalloy was determined. Through a judicious addition of lanthanum, the levels of both oxygen and sulfur were reduced to less than 10 ppm with a minimum of retained rare earth. Stress rupture ductility was increased, creep rate was lowered and hot workability was improved. No undesirable structural features were produced. The potential of rare earth elements to counteract arsenic, tin, antimony, selenium and other tramp elements is discussed.