Tensile Behavior and Microstructural Evolution of the Polycrystalline Nickel-Based Superalloy Applied in Turbine Disk

In the present study, the mechanical behaviors and microstructural evolution of the nickel-based superalloy FGH97 at different temperatures and strain rates were studied. First, the tensile tests were conducted at temperatures of 20°C, 450°C and 700°C, respectively, at two specified strain rates of 0.00025 s^-1 and 0.001 s^-1. Second, the microscopic observations of the sections were carried out to analyze the microstructure feature. Based on the test data and the observations, it was found that the influence of strain rate on the deformation and elongation will be weakened at higher temperature. Furthermore, the phenomenon of stress serrations and the intermedia temperature brittleness were just observed at 450°C, and the reason for that was investigated.