The Role of Ti on Reducing the Misfit of a Co‐Al‐W Alloy

The role of Ti on a new Co-based gamma/gamma' two phase superalloy was investigated. Scanning Electron Microscopy(SEM), X-ray Diffraction(XRD) were employed to study the microstructure of alloys with various Ti contents. The volume of gamma' rise steadily with the increase of Ti content, and the morphology switched from fine rod-like to regular cubical when the Ti concentration is over 6%. The addition of Ti reduced the misfit between gamma/gamma' phase, the misfit of the alloy with 8% Ti was only 0.15%. The room temperature hardness was improved with the increase of Ti content, which peaked when the Ti content is 8%, then dropped. The results indicated that Ti is an key element in the alloying development of Co-Al-W based superalloys.