Microalloying effects of Y on performance of cast nickel-based superalloy IN713C

Abstract

Microalloying is a cost-effective strategy to develop high performance nickel-based superalloys. Here, the mechanisms of rare earth Y in IN713C on purification, mechanical property improvement, and microstructure modification were systematically investigated. Via melt purification of Y, the O, N, and S elements are reduced to 5 ppm in the IN713C alloy. By adding Y to 74 ppm, the yield strength, tensile strength, and elongation of the IN713C alloy at 650 °C are increased by 12.2%, 14.5%, and 66%, respectively. Microstructure analysis indicated that the strength of the alloy is improved by refining the size and increasing the volume fraction of the γ’ phase. The plasticity of the alloy is improved by modifying the morphology and distribution of MC carbides. The modification of carbide morphology can be attributed to the enrichment of Y at the surface of carbides and the change of segregation of Nb, which is the main carbide-formation element.