| Title |
Deformation Behavior of Superalloy 718 under Compression Load |
| Authors |
김두현(Doo Hyun Kim); 김학민(Hak Min Kim); 박로광(Nho Kwang Park) |
| Abstract |
Wrought superalloy 718 is the most widely used nickel-base superalloy for high temperature applications. This study is aimed at illustrating deformation behavior and microstructural changes under hot forging conditions. Compression tests were conducted under argon atmosphere up to the strain 1.0, at temperatures between 930℃ and 1030℃, and at strain rates between l0^(-3)s^(-1) and 10¹s^(-1). Deformation mode is greatly affected not by the temperature, but by the strain rate under the test conditions. The specimens deform uniformly and dynamic recrystallization occurs prominently at the strain rates below 10^(-1)s^(-1). but the localized shearing governs the deformation mode and the microbands are formed at the strain rates above 10^(-1)s^(-1). To refine microstructures through dynamic recrystallization, the strain rate should be controlled to be below 10^(-1)s^(-1) and the temperature to be 930℃∼1030℃. The activation energy for dynamic recrystallization is 238∼325kJ/㏖. |