Microstructure evolution of electron beam physical vapour deposited Ni-23.5Cr-2.66Co-1.44Al Superalloy sheet during annealing at 600°C

Microstructure evolution of electron beam physical vapour deposited (EB-PVD) Ni-23.5Cr-2.66Co-1.44Al superalloy sheet during annealing at 600°C was investigated. The results showed that the as-deposited alloy was composed of only λ phase. After annealing at 600°C, the locations of diffraction peaks were still the same. The (220) diffraction peak of the deposition side increased with annealing time. The sheet on deposited side had a tendency toward forming (220) texture during post-Annealing. No obvious texture was observed at as-deposited and annealed sheet at 600°C in substrate side. The count and size of "voids" decreased with time. The size of grains increased obviously with annealing time. The ultimate tensile strength of EB-PVD Ni-23.5Cr-2.66Co-1.44Al alloy sheet increased from 641 MPa to 829 MPa after annealing at 600°C for 30 hours.