Microstructure and mechanical properties of ODS Ni-based superalloy foil produced by EB-PVD

Y₂O₃ dispersion strengthened Ni-based superalloy foil 0.1 mm thick was deposited by EB-PVD technology and followed by hot isostatic pressing (HIP) treatment. The phase composition and microstructure investigations on as-deposited and HIPed superalloy foils were performed by XRD, SEM and TEM. Columnar crystals formed on the evaporation side and equiaxed grains formed on the substrate side. Cross-section observation showed 150-300 nm grains of matrix with 10-25 nm particles of Y₂O₃ homogeneously dispersed in them. After HIP treatment, columnar crystals broke and turned into equiaxed grains. Little growth of oxide dispersoids was observed. The results of room temperature tensile tests indicated that the tensile and plastic properties of the foil after HIP treatment are both promoted with the ultimate tensile strength and elongation percentage reached the values of 1230 MPa and 0.92 in contrast with 725 MPa and 0.49 that of the as-deposited foil, respectively.