The effects of thermal exposure on the high temperature behaviour of a Laser Powder Bed Fused nickel based superalloy C263

Abstract

Additive manufacturing (AM) processes are currently being investigated to determine their suitability for wider adoption in the aero engine industry where material consistency and structural integrity are essential. A key driver is the ability of AM to produce near net-shape components and complex geometries, reducing material wastage and traditional processing stages. However, one major limitation remains in the anisotropic structures due to the complex thermal history of the process. Previous studies have employed heat treatment schedules attempting to alleviate such behaviour, although little research is currently available that explores microstructural evolution of AM alloys at in-service temperature conditions. In this research, the effects of thermal exposure on microstructure and mechanical behaviour of Laser Powder Bed Fused (LPBF) C263 is evaluated and assessed against a Cast equivalent. Results show that when exposing Cast and LPBF C263 samples to service temperatures for an extended period of time, the materials experience microstructural and chemical alterations directly controlling the mechanical response. The thermal exposure programme has demonstrated that with the precipitation of carbide phases in the exposed LPBF variant, grain boundary morphologies are highly comparable to the wrought equivalent of the same alloy.