Microstructure and properties of Ni-based superalloy sheet prepared by EB-PVD
(1.School of Astronautics, Harbin Institute of Technology, Harbin 150001, China2.Center for Composite Materials, Harbin Institute of Technology, Harbin 150080, China3.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001.P.R.China4.Center for Composite Materials and Structure, Harbin Institute of Technology, Harbin 150001, China)
Abstract: Large-scale Ni-based superalloy sheet was prepared by electron beam physical vapour deposition. Microstructures and micropores of as-deposited and heat treated superalloy sheets were studied by scanning electron microscope, atomic force microscope, and optical microscope. The results show that the as-deposited superalloy sheet is mainly composed of columnar grain, whose major axes are parallel to the normal line of the sheet. The average diameter of crystalline grains in minor axis direction is about 300nm. After heat treatment, the superalloy sheet consists of equiaxed grains, the nanopores with high interfacial energy gather and form fewer pores with larger size, and there is notable increase in toughness.
Key words: electron beam physical vapour deposition； superalloy sheet； microstructure； toughness