Abstract
This article aims to present the effect of Si addition on the microstructure, elemental partitioning, high temperature hardness, and oxidation behavior for γ′-bearing Co-based superalloy. The fraction of γ′ phase can be increased with the addition of Si, rendering an improvement on hardness at elevated temperatures. Furthermore, Si partitions preferentially toward γ′ phase and affects partitioning behavior of W. Isothermal oxidation tests conducted at 900°C, 1000°C, and 1150°C have indicated that Si additions can improve oxidation resistance. Furthermore, the content of W can have a profound impact on the oxidation behavior; low content of W can reder the formation of protective Al 2 O 3 at temperatures at and above 1000°C, while high W content can slow down oxidation at 900°C.