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With cold rolling deformation between 12.5% and 60% for GH 536 superalloy strips, effect of deformation on the mechanical properties, texture formation and microstructure evolution have been investigated. The results show that an increase of deformation will lead to an increase of mechanical properties. As the deformation was 60%, the tensile strength and yield strength of the strip were 1430MPa and 1370MPa, respectively, and the elongation of strip was 4.5%. Also, an increase of deformation will lead to an increase of hardness, yield ratio and deformation resistance as well as an increase of rolling textures such as Goss {110}, S{213}, Copper {112} and especially Brass {110}. The optimized processing parameters of cold rolling deformation between 25% and 37.5% have been proposed to obtain an excellent formability and cold workability for GH 536 superalloy strips.

An investigation of low temperature hot corrosion is carried out on a spray-formed nickel-based superalloy FGH100 pre-coated with Na2SO4-NaCl at 700 °C for 100 h. Mass gain measurement, x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy are used to study the corrosion behavior. Results reveal that corrosion behavior follows a sequence, that is, first rapidly proceeding, then gradually slowing down, and finally forming an outer layer composed of different types of oxides and an inner layer mainly comprised of sulfides. In-depth analysis reveals that the hot corrosion of FGH100 is a combined effect of oxidation-sulfidation and transfer of oxides.

The deposited billet of a new type powder metallurgy (PM) superalloy FGH4095M for use in turbine disk manufacturing has been fabricated using spray forming technology. The metallurgical quality of the deposited billet was analyzed in terms of density, texture, and grain size. Comparative research was done on the microstructure and mechanical properties between the flat disk preform prepared with hot isostatic pressing (HIP) and the same alloy forgings prepared with HIP followed by isothermal forging (IF). The results show that the density of the spray-formed and nitrogen-atomized deposit billet is above 99% of the theoretical density, indicating a compact structure. The grains are uniform and fine. The billet has weak texture with a random distribution in the spray deposition direction and perpendicular to the direction of deposition. A part of atomizing nitrogen exists in the preform in the form of carbonitride. Nitrogen-induced microporosity causes the density reduction of the preform. Compared with the process of HIP+IF, the superalloy FGH4095M after HIP has better mechanical properties at both room temperature and high temperature. The sizes of the γ' phase are finer in microstructure of the preform after HIP in comparison with the forgings after HIP+IF. This work shows that SF+HIP is a viable processing route for FGH4095M as a turbine-disk material.