High Temperature Tensile Deformation Behavior of Haynes230 Nickel Base Superalloy

Tensile experiments were conducted at different temperatures for the Haynes230 nickel-based alloy, and the microscopic mechanism of the tensile deformation behavior at high temperatures was investigated using electron backscattered diffraction (EBSD) technique. It is shown that Haynes materials have a high resistance to plastic deformation until 800 degrees C. At 650 degrees C, the materials show a significant dynamic strain aging (DSA) phenomenon, and the DSA effect is similar at 700 and 800 degrees C, and the DSA effect is weakest at 760 degrees C. The strengthening effect of DSA effect makes the alloy still maintain high strength at 650 degrees C, and the tensile strength at 800 degrees C does not decrease much compared with that at 760 degrees C. The EBSD results show that a large number of deformed twins appear near the fracture at room temperature, and the grain orientation is dominated by <111>; the <111> orientation of the tissue near the fracture is more obvious at 650 degrees C, and the grain boundaries are bent and deformed, which increases the resistance to dislocation movement; with the increase of temperature, dynamic recrystallization grains appear in the intergranular and intracrystalline areas near the fracture.